/* Copyright (C) 2000-2006 MySQL AB This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* Basic functions needed by many modules */ #include "mysql_priv.h" #include "sql_select.h" #include "sp_head.h" #include "sp.h" #include "sql_trigger.h" #include #include #include #ifdef __WIN__ #include #endif #define FLAGSTR(S,F) ((S) & (F) ? #F " " : "") /** This internal handler is used to trap internally errors that can occur when executing open table during the prelocking phase. */ class Prelock_error_handler : public Internal_error_handler { public: Prelock_error_handler() : m_handled_errors(0), m_unhandled_errors(0) {} virtual ~Prelock_error_handler() {} virtual bool handle_error(uint sql_errno, const char *message, MYSQL_ERROR::enum_warning_level level, THD *thd); bool safely_trapped_errors(); private: int m_handled_errors; int m_unhandled_errors; }; bool Prelock_error_handler::handle_error(uint sql_errno, const char * /* message */, MYSQL_ERROR::enum_warning_level /* level */, THD * /* thd */) { if (sql_errno == ER_NO_SUCH_TABLE) { m_handled_errors++; return TRUE; } m_unhandled_errors++; return FALSE; } bool Prelock_error_handler::safely_trapped_errors() { /* If m_unhandled_errors != 0, something else, unanticipated, happened, so the error is not trapped but returned to the caller. Multiple ER_NO_SUCH_TABLE can be raised in case of views. */ return ((m_handled_errors > 0) && (m_unhandled_errors == 0)); } /** @defgroup Data_Dictionary Data Dictionary @{ */ TABLE *unused_tables; /* Used by mysql_test */ HASH open_cache; /* Used by mysql_test */ static HASH table_def_cache; static TABLE_SHARE *oldest_unused_share, end_of_unused_share; static pthread_mutex_t LOCK_table_share; static bool table_def_inited= 0; static int open_unireg_entry(THD *thd, TABLE *entry, TABLE_LIST *table_list, const char *alias, char *cache_key, uint cache_key_length, MEM_ROOT *mem_root, uint flags); static void free_cache_entry(TABLE *entry); static bool open_new_frm(THD *thd, TABLE_SHARE *share, const char *alias, uint db_stat, uint prgflag, uint ha_open_flags, TABLE *outparam, TABLE_LIST *table_desc, MEM_ROOT *mem_root); static void close_old_data_files(THD *thd, TABLE *table, bool morph_locks, bool send_refresh); static bool has_two_write_locked_tables_with_auto_increment(TABLE_LIST *tables); extern "C" uchar *table_cache_key(const uchar *record, size_t *length, my_bool not_used __attribute__((unused))) { TABLE *entry=(TABLE*) record; *length= entry->s->table_cache_key.length; return (uchar*) entry->s->table_cache_key.str; } bool table_cache_init(void) { return hash_init(&open_cache, &my_charset_bin, table_cache_size+16, 0, 0, table_cache_key, (hash_free_key) free_cache_entry, 0) != 0; } void table_cache_free(void) { DBUG_ENTER("table_cache_free"); if (table_def_inited) { close_cached_tables(NULL, NULL, FALSE, FALSE, FALSE); if (!open_cache.records) // Safety first hash_free(&open_cache); } DBUG_VOID_RETURN; } uint cached_open_tables(void) { return open_cache.records; } #ifdef EXTRA_DEBUG static void check_unused(void) { uint count= 0, open_files= 0, idx= 0; TABLE *cur_link,*start_link; if ((start_link=cur_link=unused_tables)) { do { if (cur_link != cur_link->next->prev || cur_link != cur_link->prev->next) { DBUG_PRINT("error",("Unused_links aren't linked properly")); /* purecov: inspected */ return; /* purecov: inspected */ } } while (count++ < open_cache.records && (cur_link=cur_link->next) != start_link); if (cur_link != start_link) { DBUG_PRINT("error",("Unused_links aren't connected")); /* purecov: inspected */ } } for (idx=0 ; idx < open_cache.records ; idx++) { TABLE *entry=(TABLE*) hash_element(&open_cache,idx); if (!entry->in_use) count--; if (entry->file) open_files++; } if (count != 0) { DBUG_PRINT("error",("Unused_links doesn't match open_cache: diff: %d", /* purecov: inspected */ count)); /* purecov: inspected */ } #ifdef NOT_SAFE_FOR_REPAIR /* check that open cache and table definition cache has same number of aktive tables */ count= 0; for (idx=0 ; idx < table_def_cache.records ; idx++) { TABLE_SHARE *entry= (TABLE_SHARE*) hash_element(&table_def_cache,idx); count+= entry->ref_count; } if (count != open_files) { DBUG_PRINT("error", ("table_def ref_count: %u open_cache: %u", count, open_files)); DBUG_ASSERT(count == open_files); } #endif } #else #define check_unused() #endif /* Create a table cache key SYNOPSIS create_table_def_key() thd Thread handler key Create key here (must be of size MAX_DBKEY_LENGTH) table_list Table definition tmp_table Set if table is a tmp table IMPLEMENTATION The table cache_key is created from: db_name + \0 table_name + \0 if the table is a tmp table, we add the following to make each tmp table unique on the slave: 4 bytes for master thread id 4 bytes pseudo thread id RETURN Length of key */ uint create_table_def_key(THD *thd, char *key, TABLE_LIST *table_list, bool tmp_table) { uint key_length= (uint) (strmov(strmov(key, table_list->db)+1, table_list->table_name)-key)+1; if (tmp_table) { int4store(key + key_length, thd->server_id); int4store(key + key_length + 4, thd->variables.pseudo_thread_id); key_length+= TMP_TABLE_KEY_EXTRA; } return key_length; } /***************************************************************************** Functions to handle table definition cach (TABLE_SHARE) *****************************************************************************/ extern "C" uchar *table_def_key(const uchar *record, size_t *length, my_bool not_used __attribute__((unused))) { TABLE_SHARE *entry=(TABLE_SHARE*) record; *length= entry->table_cache_key.length; return (uchar*) entry->table_cache_key.str; } static void table_def_free_entry(TABLE_SHARE *share) { DBUG_ENTER("table_def_free_entry"); if (share->prev) { /* remove from old_unused_share list */ pthread_mutex_lock(&LOCK_table_share); *share->prev= share->next; share->next->prev= share->prev; pthread_mutex_unlock(&LOCK_table_share); } free_table_share(share); DBUG_VOID_RETURN; } bool table_def_init(void) { table_def_inited= 1; pthread_mutex_init(&LOCK_table_share, MY_MUTEX_INIT_FAST); oldest_unused_share= &end_of_unused_share; end_of_unused_share.prev= &oldest_unused_share; return hash_init(&table_def_cache, &my_charset_bin, table_def_size, 0, 0, table_def_key, (hash_free_key) table_def_free_entry, 0) != 0; } void table_def_free(void) { DBUG_ENTER("table_def_free"); if (table_def_inited) { table_def_inited= 0; pthread_mutex_destroy(&LOCK_table_share); hash_free(&table_def_cache); } DBUG_VOID_RETURN; } uint cached_table_definitions(void) { return table_def_cache.records; } /* Get TABLE_SHARE for a table. get_table_share() thd Thread handle table_list Table that should be opened key Table cache key key_length Length of key db_flags Flags to open_table_def(): OPEN_VIEW error out: Error code from open_table_def() IMPLEMENTATION Get a table definition from the table definition cache. If it doesn't exist, create a new from the table definition file. NOTES We must have wrlock on LOCK_open when we come here (To be changed later) RETURN 0 Error # Share for table */ TABLE_SHARE *get_table_share(THD *thd, TABLE_LIST *table_list, char *key, uint key_length, uint db_flags, int *error) { TABLE_SHARE *share; DBUG_ENTER("get_table_share"); *error= 0; /* Read table definition from cache */ if ((share= (TABLE_SHARE*) hash_search(&table_def_cache,(uchar*) key, key_length))) goto found; if (!(share= alloc_table_share(table_list, key, key_length))) { #ifdef WAITING_FOR_TABLE_DEF_CACHE_STAGE_3 pthread_mutex_unlock(&LOCK_open); #endif DBUG_RETURN(0); } #ifdef WAITING_FOR_TABLE_DEF_CACHE_STAGE_3 // We need a write lock to be able to add a new entry pthread_mutex_unlock(&LOCK_open); pthread_mutex_lock(&LOCK_open); /* Check that another thread didn't insert the same table in between */ if ((old_share= hash_search(&table_def_cache, (uchar*) key, key_length))) { (void) pthread_mutex_lock(&share->mutex); free_table_share(share); share= old_share; goto found; } #endif /* Lock mutex to be able to read table definition from file without conflicts */ (void) pthread_mutex_lock(&share->mutex); /* We assign a new table id under the protection of the LOCK_open and the share's own mutex. We do this insted of creating a new mutex and using it for the sole purpose of serializing accesses to a static variable, we assign the table id here. We assign it to the share before inserting it into the table_def_cache to be really sure that it cannot be read from the cache without having a table id assigned. CAVEAT. This means that the table cannot be used for binlogging/replication purposes, unless get_table_share() has been called directly or indirectly. */ assign_new_table_id(share); if (my_hash_insert(&table_def_cache, (uchar*) share)) { #ifdef WAITING_FOR_TABLE_DEF_CACHE_STAGE_3 pthread_mutex_unlock(&LOCK_open); (void) pthread_mutex_unlock(&share->mutex); #endif free_table_share(share); DBUG_RETURN(0); // return error } #ifdef WAITING_FOR_TABLE_DEF_CACHE_STAGE_3 pthread_mutex_unlock(&LOCK_open); #endif if (open_table_def(thd, share, db_flags)) { #ifdef WAITING_FOR_TABLE_DEF_CACHE_STAGE_3 /* No such table or wrong table definition file Lock first the table cache and then the mutex. This will ensure that no other thread is using the share structure. */ (void) pthread_mutex_unlock(&share->mutex); (void) pthread_mutex_lock(&LOCK_open); (void) pthread_mutex_lock(&share->mutex); #endif *error= share->error; (void) hash_delete(&table_def_cache, (uchar*) share); DBUG_RETURN(0); } share->ref_count++; // Mark in use DBUG_PRINT("exit", ("share: 0x%lx ref_count: %u", (ulong) share, share->ref_count)); (void) pthread_mutex_unlock(&share->mutex); DBUG_RETURN(share); found: /* We found an existing table definition. Return it if we didn't get an error when reading the table definition from file. */ /* We must do a lock to ensure that the structure is initialized */ (void) pthread_mutex_lock(&share->mutex); #ifdef WAITING_FOR_TABLE_DEF_CACHE_STAGE_3 pthread_mutex_unlock(&LOCK_open); #endif if (share->error) { /* Table definition contained an error */ open_table_error(share, share->error, share->open_errno, share->errarg); (void) pthread_mutex_unlock(&share->mutex); DBUG_RETURN(0); } if (share->is_view && !(db_flags & OPEN_VIEW)) { open_table_error(share, 1, ENOENT, 0); (void) pthread_mutex_unlock(&share->mutex); DBUG_RETURN(0); } if (!share->ref_count++ && share->prev) { /* Share was not used before and it was in the old_unused_share list Unlink share from this list */ DBUG_PRINT("info", ("Unlinking from not used list")); pthread_mutex_lock(&LOCK_table_share); *share->prev= share->next; share->next->prev= share->prev; share->next= 0; share->prev= 0; pthread_mutex_unlock(&LOCK_table_share); } (void) pthread_mutex_unlock(&share->mutex); /* Free cache if too big */ while (table_def_cache.records > table_def_size && oldest_unused_share->next) { pthread_mutex_lock(&oldest_unused_share->mutex); VOID(hash_delete(&table_def_cache, (uchar*) oldest_unused_share)); } DBUG_PRINT("exit", ("share: 0x%lx ref_count: %u", (ulong) share, share->ref_count)); DBUG_RETURN(share); } /* Get a table share. If it didn't exist, try creating it from engine For arguments and return values, see get_table_from_share() */ static TABLE_SHARE *get_table_share_with_create(THD *thd, TABLE_LIST *table_list, char *key, uint key_length, uint db_flags, int *error) { TABLE_SHARE *share; int tmp; DBUG_ENTER("get_table_share_with_create"); share= get_table_share(thd, table_list, key, key_length, db_flags, error); /* If share is not NULL, we found an existing share. If share is NULL, and there is no error, we're inside pre-locking, which silences 'ER_NO_SUCH_TABLE' errors with the intention to silently drop non-existing tables from the pre-locking list. In this case we still need to try auto-discover before returning a NULL share. If share is NULL and the error is ER_NO_SUCH_TABLE, this is the same as above, only that the error was not silenced by pre-locking. Once again, we need to try to auto-discover the share. Finally, if share is still NULL, it's a real error and we need to abort. @todo Rework alternative ways to deal with ER_NO_SUCH TABLE. */ if (share || thd->is_error() && thd->main_da.sql_errno() != ER_NO_SUCH_TABLE) DBUG_RETURN(share); /* Table didn't exist. Check if some engine can provide it */ if ((tmp= ha_create_table_from_engine(thd, table_list->db, table_list->table_name)) < 0) { /* No such table in any engine. Hide "Table doesn't exist" errors if the table belongs to a view. The check for thd->is_error() is necessary to not push an unwanted error in case of pre-locking, which silences "no such table" errors. @todo Rework the alternative ways to deal with ER_NO_SUCH TABLE. */ if (thd->is_error() && table_list->belong_to_view) { TABLE_LIST *view= table_list->belong_to_view; thd->clear_error(); my_error(ER_VIEW_INVALID, MYF(0), view->view_db.str, view->view_name.str); } DBUG_RETURN(0); } if (tmp) { /* Give right error message */ thd->clear_error(); DBUG_PRINT("error", ("Discovery of %s/%s failed", table_list->db, table_list->table_name)); my_printf_error(ER_UNKNOWN_ERROR, "Failed to open '%-.64s', error while " "unpacking from engine", MYF(0), table_list->table_name); DBUG_RETURN(0); } /* Table existed in engine. Let's open it */ mysql_reset_errors(thd, 1); // Clear warnings thd->clear_error(); // Clear error message DBUG_RETURN(get_table_share(thd, table_list, key, key_length, db_flags, error)); } /* Mark that we are not using table share anymore. SYNOPSIS release_table_share() share Table share release_type How the release should be done: RELEASE_NORMAL - Release without checking RELEASE_WAIT_FOR_DROP - Don't return until we get a signal that the table is deleted or the thread is killed. IMPLEMENTATION If ref_count goes to zero and (we have done a refresh or if we have already too many open table shares) then delete the definition. If type == RELEASE_WAIT_FOR_DROP then don't return until we get a signal that the table is deleted or the thread is killed. */ void release_table_share(TABLE_SHARE *share, enum release_type type) { bool to_be_deleted= 0; DBUG_ENTER("release_table_share"); DBUG_PRINT("enter", ("share: 0x%lx table: %s.%s ref_count: %u version: %lu", (ulong) share, share->db.str, share->table_name.str, share->ref_count, share->version)); safe_mutex_assert_owner(&LOCK_open); pthread_mutex_lock(&share->mutex); if (!--share->ref_count) { if (share->version != refresh_version) to_be_deleted=1; else { /* Link share last in used_table_share list */ DBUG_PRINT("info",("moving share to unused list")); DBUG_ASSERT(share->next == 0); pthread_mutex_lock(&LOCK_table_share); share->prev= end_of_unused_share.prev; *end_of_unused_share.prev= share; end_of_unused_share.prev= &share->next; share->next= &end_of_unused_share; pthread_mutex_unlock(&LOCK_table_share); to_be_deleted= (table_def_cache.records > table_def_size); } } if (to_be_deleted) { DBUG_PRINT("info", ("Deleting share")); hash_delete(&table_def_cache, (uchar*) share); DBUG_VOID_RETURN; } pthread_mutex_unlock(&share->mutex); DBUG_VOID_RETURN; #ifdef WAITING_FOR_TABLE_DEF_CACHE_STAGE_3 if (to_be_deleted) { /* We must try again with new locks as we must get LOCK_open before share->mutex */ pthread_mutex_unlock(&share->mutex); pthread_mutex_lock(&LOCK_open); pthread_mutex_lock(&share->mutex); if (!share->ref_count) { // No one is using this now TABLE_SHARE *name_lock; if (share->replace_with_name_lock && (name_lock=get_name_lock(share))) { /* This code is execured when someone does FLUSH TABLES while on has locked tables. */ (void) hash_search(&def_cache,(uchar*) key,key_length); hash_replace(&def_cache, def_cache.current_record,(uchar*) name_lock); } else { /* Remove table definition */ hash_delete(&def_cache,(uchar*) share); } pthread_mutex_unlock(&LOCK_open); free_table_share(share); } else { pthread_mutex_unlock(&LOCK_open); if (type == RELEASE_WAIT_FOR_DROP) wait_for_table(share, "Waiting for close"); else pthread_mutex_unlock(&share->mutex); } } else if (type == RELEASE_WAIT_FOR_DROP) wait_for_table(share, "Waiting for close"); else pthread_mutex_unlock(&share->mutex); #endif } /* Check if table definition exits in cache SYNOPSIS get_cached_table_share() db Database name table_name Table name RETURN 0 Not cached # TABLE_SHARE for table */ TABLE_SHARE *get_cached_table_share(const char *db, const char *table_name) { char key[NAME_LEN*2+2]; TABLE_LIST table_list; uint key_length; safe_mutex_assert_owner(&LOCK_open); table_list.db= (char*) db; table_list.table_name= (char*) table_name; key_length= create_table_def_key((THD*) 0, key, &table_list, 0); return (TABLE_SHARE*) hash_search(&table_def_cache,(uchar*) key, key_length); } /* Close file handle, but leave the table in the table cache SYNOPSIS close_handle_and_leave_table_as_lock() table Table handler NOTES By leaving the table in the table cache, it disallows any other thread to open the table thd->killed will be set if we run out of memory If closing a MERGE child, the calling function has to take care for closing the parent too, if necessary. */ void close_handle_and_leave_table_as_lock(TABLE *table) { TABLE_SHARE *share, *old_share= table->s; char *key_buff; MEM_ROOT *mem_root= &table->mem_root; DBUG_ENTER("close_handle_and_leave_table_as_lock"); DBUG_ASSERT(table->db_stat); /* Make a local copy of the table share and free the current one. This has to be done to ensure that the table share is removed from the table defintion cache as soon as the last instance is removed */ if (multi_alloc_root(mem_root, &share, sizeof(*share), &key_buff, old_share->table_cache_key.length, NULL)) { bzero((char*) share, sizeof(*share)); share->set_table_cache_key(key_buff, old_share->table_cache_key.str, old_share->table_cache_key.length); share->tmp_table= INTERNAL_TMP_TABLE; // for intern_close_table() } /* When closing a MERGE parent or child table, detach the children first. Do not clear child table references to allow for reopen. */ if (table->child_l || table->parent) detach_merge_children(table, FALSE); table->file->close(); table->db_stat= 0; // Mark file closed release_table_share(table->s, RELEASE_NORMAL); table->s= share; DBUG_VOID_RETURN; } /* Create a list for all open tables matching SQL expression SYNOPSIS list_open_tables() thd Thread THD wild SQL like expression NOTES One gets only a list of tables for which one has any kind of privilege. db and table names are allocated in result struct, so one doesn't need a lock on LOCK_open when traversing the return list. RETURN VALUES NULL Error (Probably OOM) # Pointer to list of names of open tables. */ OPEN_TABLE_LIST *list_open_tables(THD *thd, const char *db, const char *wild) { int result = 0; OPEN_TABLE_LIST **start_list, *open_list; TABLE_LIST table_list; DBUG_ENTER("list_open_tables"); VOID(pthread_mutex_lock(&LOCK_open)); bzero((char*) &table_list,sizeof(table_list)); start_list= &open_list; open_list=0; for (uint idx=0 ; result == 0 && idx < open_cache.records; idx++) { OPEN_TABLE_LIST *table; TABLE *entry=(TABLE*) hash_element(&open_cache,idx); TABLE_SHARE *share= entry->s; if (db && my_strcasecmp(system_charset_info, db, share->db.str)) continue; if (wild && wild_compare(share->table_name.str, wild, 0)) continue; /* Check if user has SELECT privilege for any column in the table */ table_list.db= share->db.str; table_list.table_name= share->table_name.str; table_list.grant.privilege=0; if (check_table_access(thd,SELECT_ACL | EXTRA_ACL,&table_list,1)) continue; /* need to check if we haven't already listed it */ for (table= open_list ; table ; table=table->next) { if (!strcmp(table->table, share->table_name.str) && !strcmp(table->db, share->db.str)) { if (entry->in_use) table->in_use++; if (entry->locked_by_name) table->locked++; break; } } if (table) continue; if (!(*start_list = (OPEN_TABLE_LIST *) sql_alloc(sizeof(**start_list)+share->table_cache_key.length))) { open_list=0; // Out of memory break; } strmov((*start_list)->table= strmov(((*start_list)->db= (char*) ((*start_list)+1)), share->db.str)+1, share->table_name.str); (*start_list)->in_use= entry->in_use ? 1 : 0; (*start_list)->locked= entry->locked_by_name ? 1 : 0; start_list= &(*start_list)->next; *start_list=0; } VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(open_list); } /***************************************************************************** * Functions to free open table cache ****************************************************************************/ void intern_close_table(TABLE *table) { // Free all structures DBUG_ENTER("intern_close_table"); DBUG_PRINT("tcache", ("table: '%s'.'%s' 0x%lx", table->s ? table->s->db.str : "?", table->s ? table->s->table_name.str : "?", (long) table)); free_io_cache(table); delete table->triggers; if (table->file) // Not true if name lock VOID(closefrm(table, 1)); // close file DBUG_VOID_RETURN; } /* Remove table from the open table cache SYNOPSIS free_cache_entry() table Table to remove NOTE We need to have a lock on LOCK_open when calling this */ static void free_cache_entry(TABLE *table) { DBUG_ENTER("free_cache_entry"); /* Assert that MERGE children are not attached before final close. */ DBUG_ASSERT(!table->is_children_attached()); intern_close_table(table); if (!table->in_use) { table->next->prev=table->prev; /* remove from used chain */ table->prev->next=table->next; if (table == unused_tables) { unused_tables=unused_tables->next; if (table == unused_tables) unused_tables=0; } check_unused(); // consisty check } my_free((uchar*) table,MYF(0)); DBUG_VOID_RETURN; } /* Free resources allocated by filesort() and read_record() */ void free_io_cache(TABLE *table) { DBUG_ENTER("free_io_cache"); if (table->sort.io_cache) { close_cached_file(table->sort.io_cache); my_free((uchar*) table->sort.io_cache,MYF(0)); table->sort.io_cache=0; } DBUG_VOID_RETURN; } /* Close all tables which aren't in use by any thread @param thd Thread context @param tables List of tables to remove from the cache @param have_lock If LOCK_open is locked @param wait_for_refresh Wait for a impending flush @param wait_for_placeholders Wait for tables being reopened so that the GRL won't proceed while write-locked tables are being reopened by other threads. @remark THD can be NULL, but then wait_for_refresh must be FALSE and tables must be NULL. */ bool close_cached_tables(THD *thd, TABLE_LIST *tables, bool have_lock, bool wait_for_refresh, bool wait_for_placeholders) { bool result=0; DBUG_ENTER("close_cached_tables"); DBUG_ASSERT(thd || (!wait_for_refresh && !tables)); if (!have_lock) VOID(pthread_mutex_lock(&LOCK_open)); if (!tables) { refresh_version++; // Force close of open tables while (unused_tables) { #ifdef EXTRA_DEBUG if (hash_delete(&open_cache,(uchar*) unused_tables)) printf("Warning: Couldn't delete open table from hash\n"); #else VOID(hash_delete(&open_cache,(uchar*) unused_tables)); #endif } /* Free table shares */ while (oldest_unused_share->next) { pthread_mutex_lock(&oldest_unused_share->mutex); VOID(hash_delete(&table_def_cache, (uchar*) oldest_unused_share)); } DBUG_PRINT("tcache", ("incremented global refresh_version to: %lu", refresh_version)); if (wait_for_refresh) { /* Other threads could wait in a loop in open_and_lock_tables(), trying to lock one or more of our tables. If they wait for the locks in thr_multi_lock(), their lock request is aborted. They loop in open_and_lock_tables() and enter open_table(). Here they notice the table is refreshed and wait for COND_refresh. Then they loop again in open_and_lock_tables() and this time open_table() succeeds. At this moment, if we (the FLUSH TABLES thread) are scheduled and on another FLUSH TABLES enter close_cached_tables(), they could awake while we sleep below, waiting for others threads (us) to close their open tables. If this happens, the other threads would find the tables unlocked. They would get the locks, one after the other, and could do their destructive work. This is an issue if we have LOCK TABLES in effect. The problem is that the other threads passed all checks in open_table() before we refresh the table. The fix for this problem is to set some_tables_deleted for all threads with open tables. These threads can still get their locks, but will immediately release them again after checking this variable. They will then loop in open_and_lock_tables() again. There they will wait until we update all tables version below. Setting some_tables_deleted is done by remove_table_from_cache() in the other branch. In other words (reviewer suggestion): You need this setting of some_tables_deleted for the case when table was opened and all related checks were passed before incrementing refresh_version (which you already have) but attempt to lock the table happened after the call to close_old_data_files() i.e. after removal of current thread locks. */ for (uint idx=0 ; idx < open_cache.records ; idx++) { TABLE *table=(TABLE*) hash_element(&open_cache,idx); if (table->in_use) table->in_use->some_tables_deleted= 1; } } } else { bool found=0; for (TABLE_LIST *table= tables; table; table= table->next_local) { if (remove_table_from_cache(thd, table->db, table->table_name, RTFC_OWNED_BY_THD_FLAG)) found=1; } if (!found) wait_for_refresh=0; // Nothing to wait for } #ifndef EMBEDDED_LIBRARY if (!tables) kill_delayed_threads(); #endif if (wait_for_refresh) { /* If there is any table that has a lower refresh_version, wait until this is closed (or this thread is killed) before returning */ thd->mysys_var->current_mutex= &LOCK_open; thd->mysys_var->current_cond= &COND_refresh; thd_proc_info(thd, "Flushing tables"); close_old_data_files(thd,thd->open_tables,1,1); mysql_ha_flush(thd); bool found=1; /* Wait until all threads has closed all the tables we had locked */ DBUG_PRINT("info", ("Waiting for other threads to close their open tables")); while (found && ! thd->killed) { found=0; for (uint idx=0 ; idx < open_cache.records ; idx++) { TABLE *table=(TABLE*) hash_element(&open_cache,idx); /* Avoid a self-deadlock. */ if (table->in_use == thd) continue; /* Note that we wait here only for tables which are actually open, and not for placeholders with TABLE::open_placeholder set. Waiting for latter will cause deadlock in the following scenario, for example: conn1: lock table t1 write; conn2: lock table t2 write; conn1: flush tables; conn2: flush tables; It also does not make sense to wait for those of placeholders that are employed by CREATE TABLE as in this case table simply does not exist yet. */ if (table->needs_reopen_or_name_lock() && (table->db_stat || (table->open_placeholder && wait_for_placeholders))) { found=1; DBUG_PRINT("signal", ("Waiting for COND_refresh")); pthread_cond_wait(&COND_refresh,&LOCK_open); break; } } } /* No other thread has the locked tables open; reopen them and get the old locks. This should always succeed (unless some external process has removed the tables) */ thd->in_lock_tables=1; result=reopen_tables(thd,1,1); thd->in_lock_tables=0; /* Set version for table */ for (TABLE *table=thd->open_tables; table ; table= table->next) { /* Preserve the version (0) of write locked tables so that a impending global read lock won't sneak in. */ if (table->reginfo.lock_type < TL_WRITE_ALLOW_WRITE) table->s->version= refresh_version; } } if (!have_lock) VOID(pthread_mutex_unlock(&LOCK_open)); if (wait_for_refresh) { pthread_mutex_lock(&thd->mysys_var->mutex); thd->mysys_var->current_mutex= 0; thd->mysys_var->current_cond= 0; thd_proc_info(thd, 0); pthread_mutex_unlock(&thd->mysys_var->mutex); } DBUG_RETURN(result); } /* Close all tables which match specified connection string or if specified string is NULL, then any table with a connection string. */ bool close_cached_connection_tables(THD *thd, bool if_wait_for_refresh, LEX_STRING *connection, bool have_lock) { uint idx; TABLE_LIST tmp, *tables= NULL; bool result= FALSE; DBUG_ENTER("close_cached_connections"); DBUG_ASSERT(thd); bzero(&tmp, sizeof(TABLE_LIST)); if (!have_lock) VOID(pthread_mutex_lock(&LOCK_open)); for (idx= 0; idx < table_def_cache.records; idx++) { TABLE_SHARE *share= (TABLE_SHARE *) hash_element(&table_def_cache, idx); /* Ignore if table is not open or does not have a connect_string */ if (!share->connect_string.length || !share->ref_count) continue; /* Compare the connection string */ if (connection && (connection->length > share->connect_string.length || (connection->length < share->connect_string.length && (share->connect_string.str[connection->length] != '/' && share->connect_string.str[connection->length] != '\\')) || strncasecmp(connection->str, share->connect_string.str, connection->length))) continue; /* close_cached_tables() only uses these elements */ tmp.db= share->db.str; tmp.table_name= share->table_name.str; tmp.next_local= tables; tables= (TABLE_LIST *) memdup_root(thd->mem_root, (char*)&tmp, sizeof(TABLE_LIST)); } if (tables) result= close_cached_tables(thd, tables, TRUE, FALSE, FALSE); if (!have_lock) VOID(pthread_mutex_unlock(&LOCK_open)); if (if_wait_for_refresh) { pthread_mutex_lock(&thd->mysys_var->mutex); thd->mysys_var->current_mutex= 0; thd->mysys_var->current_cond= 0; thd->proc_info=0; pthread_mutex_unlock(&thd->mysys_var->mutex); } DBUG_RETURN(result); } /** Mark all temporary tables which were used by the current statement or substatement as free for reuse, but only if the query_id can be cleared. @param thd thread context @remark For temp tables associated with a open SQL HANDLER the query_id is not reset until the HANDLER is closed. */ static void mark_temp_tables_as_free_for_reuse(THD *thd) { for (TABLE *table= thd->temporary_tables ; table ; table= table->next) { if ((table->query_id == thd->query_id) && ! table->open_by_handler) { table->query_id= 0; table->file->ha_reset(); /* Detach temporary MERGE children from temporary parent to allow new attach at next open. Do not do the detach, if close_thread_tables() is called from a sub-statement. The temporary table might still be used in the top-level statement. */ if (table->child_l || table->parent) detach_merge_children(table, TRUE); } } } /* Mark all tables in the list which were used by current substatement as free for reuse. SYNOPSIS mark_used_tables_as_free_for_reuse() thd - thread context table - head of the list of tables DESCRIPTION Marks all tables in the list which were used by current substatement (they are marked by its query_id) as free for reuse. NOTE The reason we reset query_id is that it's not enough to just test if table->query_id != thd->query_id to know if a table is in use. For example SELECT f1_that_uses_t1() FROM t1; In f1_that_uses_t1() we will see one instance of t1 where query_id is set to query_id of original query. */ static void mark_used_tables_as_free_for_reuse(THD *thd, TABLE *table) { for (; table ; table= table->next) { if (table->query_id == thd->query_id) { table->query_id= 0; table->file->ha_reset(); } } } /** Auxiliary function to close all tables in the open_tables list. @param thd Thread context. @remark It should not ordinarily be called directly. */ static void close_open_tables(THD *thd) { bool found_old_table= 0; safe_mutex_assert_not_owner(&LOCK_open); VOID(pthread_mutex_lock(&LOCK_open)); DBUG_PRINT("info", ("thd->open_tables: 0x%lx", (long) thd->open_tables)); while (thd->open_tables) found_old_table|= close_thread_table(thd, &thd->open_tables); thd->some_tables_deleted= 0; /* Free tables to hold down open files */ while (open_cache.records > table_cache_size && unused_tables) VOID(hash_delete(&open_cache,(uchar*) unused_tables)); /* purecov: tested */ check_unused(); if (found_old_table) { /* Tell threads waiting for refresh that something has happened */ broadcast_refresh(); } VOID(pthread_mutex_unlock(&LOCK_open)); } /* Close all tables used by the current substatement, or all tables used by this thread if we are on the upper level. SYNOPSIS close_thread_tables() thd Thread handler IMPLEMENTATION Unlocks tables and frees derived tables. Put all normal tables used by thread in free list. It will only close/mark as free for reuse tables opened by this substatement, it will also check if we are closing tables after execution of complete query (i.e. we are on upper level) and will leave prelocked mode if needed. */ void close_thread_tables(THD *thd) { TABLE *table; prelocked_mode_type prelocked_mode= thd->prelocked_mode; DBUG_ENTER("close_thread_tables"); #ifdef EXTRA_DEBUG DBUG_PRINT("tcache", ("open tables:")); for (table= thd->open_tables; table; table= table->next) DBUG_PRINT("tcache", ("table: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); #endif /* We are assuming here that thd->derived_tables contains ONLY derived tables for this substatement. i.e. instead of approach which uses query_id matching for determining which of the derived tables belong to this substatement we rely on the ability of substatements to save/restore thd->derived_tables during their execution. TODO: Probably even better approach is to simply associate list of derived tables with (sub-)statement instead of thread and destroy them at the end of its execution. */ if (thd->derived_tables) { TABLE *next; /* Close all derived tables generated in queries like SELECT * FROM (SELECT * FROM t1) */ for (table= thd->derived_tables ; table ; table= next) { next= table->next; free_tmp_table(thd, table); } thd->derived_tables= 0; } /* Mark all temporary tables used by this statement as free for reuse. */ mark_temp_tables_as_free_for_reuse(thd); if (thd->locked_tables || prelocked_mode) { /* Let us commit transaction for statement. Since in 5.0 we only have one statement transaction and don't allow several nested statement transactions this call will do nothing if we are inside of stored function or trigger (i.e. statement transaction is already active and does not belong to statement for which we do close_thread_tables()). TODO: This should be fixed in later releases. */ ha_commit_stmt(thd); /* Ensure we are calling ha_reset() for all used tables */ mark_used_tables_as_free_for_reuse(thd, thd->open_tables); /* We are under simple LOCK TABLES so should not do anything else. */ if (!prelocked_mode || !thd->lex->requires_prelocking()) DBUG_VOID_RETURN; /* We are in prelocked mode, so we have to leave it now with doing implicit UNLOCK TABLES if need. */ DBUG_PRINT("info",("thd->prelocked_mode= NON_PRELOCKED")); thd->prelocked_mode= NON_PRELOCKED; if (prelocked_mode == PRELOCKED_UNDER_LOCK_TABLES) DBUG_VOID_RETURN; thd->lock= thd->locked_tables; thd->locked_tables= 0; /* Fallthrough */ } if (thd->lock) { /* For RBR we flush the pending event just before we unlock all the tables. This means that we are at the end of a topmost statement, so we ensure that the STMT_END_F flag is set on the pending event. For statements that are *inside* stored functions, the pending event will not be flushed: that will be handled either before writing a query log event (inside binlog_query()) or when preparing a pending event. */ thd->binlog_flush_pending_rows_event(TRUE); mysql_unlock_tables(thd, thd->lock); thd->lock=0; } /* assume handlers auto-commit (if some doesn't - transaction handling in MySQL should be redesigned to support it; it's a big change, and it's not worth it - better to commit explicitly only writing transactions, read-only ones should better take care of themselves. saves some work in 2pc too) see also sql_parse.cc - dispatch_command() */ if (!(thd->state_flags & Open_tables_state::BACKUPS_AVAIL)) bzero(&thd->transaction.stmt, sizeof(thd->transaction.stmt)); if (!thd->active_transaction()) thd->transaction.xid_state.xid.null(); /* Note that we need to hold LOCK_open while changing the open_tables list. Another thread may work on it. (See: remove_table_from_cache(), mysql_wait_completed_table()) Closing a MERGE child before the parent would be fatal if the other thread tries to abort the MERGE lock in between. */ if (thd->open_tables) close_open_tables(thd); if (prelocked_mode == PRELOCKED) { /* If we are here then we are leaving normal prelocked mode, so it is good idea to turn off OPTION_TABLE_LOCK flag. */ DBUG_ASSERT(thd->lex->requires_prelocking()); thd->options&= ~(OPTION_TABLE_LOCK); } DBUG_VOID_RETURN; } /* move one table to free list */ bool close_thread_table(THD *thd, TABLE **table_ptr) { bool found_old_table= 0; TABLE *table= *table_ptr; DBUG_ENTER("close_thread_table"); DBUG_ASSERT(table->key_read == 0); DBUG_ASSERT(!table->file || table->file->inited == handler::NONE); DBUG_PRINT("tcache", ("table: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); *table_ptr=table->next; /* When closing a MERGE parent or child table, detach the children first. Clear child table references to force new assignment at next open. */ if (table->child_l || table->parent) detach_merge_children(table, TRUE); if (table->needs_reopen_or_name_lock() || thd->version != refresh_version || !table->db_stat) { VOID(hash_delete(&open_cache,(uchar*) table)); found_old_table=1; } else { /* Open placeholders have TABLE::db_stat set to 0, so they should be handled by the first alternative. */ DBUG_ASSERT(!table->open_placeholder); /* Assert that MERGE children are not attached in unused_tables. */ DBUG_ASSERT(!table->is_children_attached()); /* Free memory and reset for next loop */ table->file->ha_reset(); table->in_use=0; if (unused_tables) { table->next=unused_tables; /* Link in last */ table->prev=unused_tables->prev; unused_tables->prev=table; table->prev->next=table; } else unused_tables=table->next=table->prev=table; } DBUG_RETURN(found_old_table); } /* close_temporary_tables' internal, 4 is due to uint4korr definition */ static inline uint tmpkeyval(THD *thd, TABLE *table) { return uint4korr(table->s->table_cache_key.str + table->s->table_cache_key.length - 4); } /* Close all temporary tables created by 'CREATE TEMPORARY TABLE' for thread creates one DROP TEMPORARY TABLE binlog event for each pseudo-thread */ void close_temporary_tables(THD *thd) { TABLE *table; TABLE *next; TABLE *prev_table; /* Assume thd->options has OPTION_QUOTE_SHOW_CREATE */ bool was_quote_show= TRUE; LINT_INIT(next); if (!thd->temporary_tables) return; if (!mysql_bin_log.is_open() || thd->current_stmt_binlog_row_based) { TABLE *tmp_next; for (table= thd->temporary_tables; table; table= tmp_next) { tmp_next= table->next; close_temporary(table, 1, 1); } thd->temporary_tables= 0; return; } /* Better add "if exists", in case a RESET MASTER has been done */ const char stub[]= "DROP /*!40005 TEMPORARY */ TABLE IF EXISTS "; uint stub_len= sizeof(stub) - 1; char buf[256]; String s_query= String(buf, sizeof(buf), system_charset_info); bool found_user_tables= FALSE; memcpy(buf, stub, stub_len); /* Insertion sort of temp tables by pseudo_thread_id to build ordered list of sublists of equal pseudo_thread_id */ for (prev_table= thd->temporary_tables, table= prev_table->next; table; prev_table= table, table= table->next) { TABLE *prev_sorted /* same as for prev_table */, *sorted; if (is_user_table(table)) { if (!found_user_tables) found_user_tables= true; for (prev_sorted= NULL, sorted= thd->temporary_tables; sorted != table; prev_sorted= sorted, sorted= sorted->next) { if (!is_user_table(sorted) || tmpkeyval(thd, sorted) > tmpkeyval(thd, table)) { /* move into the sorted part of the list from the unsorted */ prev_table->next= table->next; table->next= sorted; if (prev_sorted) { prev_sorted->next= table; } else { thd->temporary_tables= table; } table= prev_table; break; } } } } /* We always quote db,table names though it is slight overkill */ if (found_user_tables && !(was_quote_show= test(thd->options & OPTION_QUOTE_SHOW_CREATE))) { thd->options |= OPTION_QUOTE_SHOW_CREATE; } /* scan sorted tmps to generate sequence of DROP */ for (table= thd->temporary_tables; table; table= next) { if (is_user_table(table)) { my_thread_id save_pseudo_thread_id= thd->variables.pseudo_thread_id; /* Set pseudo_thread_id to be that of the processed table */ thd->variables.pseudo_thread_id= tmpkeyval(thd, table); /* Loop forward through all tables within the sublist of common pseudo_thread_id to create single DROP query. */ for (s_query.length(stub_len); table && is_user_table(table) && tmpkeyval(thd, table) == thd->variables.pseudo_thread_id; table= next) { /* We are going to add 4 ` around the db/table names and possible more due to special characters in the names */ append_identifier(thd, &s_query, table->s->db.str, strlen(table->s->db.str)); s_query.append('.'); append_identifier(thd, &s_query, table->s->table_name.str, strlen(table->s->table_name.str)); s_query.append(','); next= table->next; close_temporary(table, 1, 1); } thd->clear_error(); CHARSET_INFO *cs_save= thd->variables.character_set_client; thd->variables.character_set_client= system_charset_info; Query_log_event qinfo(thd, s_query.ptr(), s_query.length() - 1 /* to remove trailing ',' */, 0, FALSE); thd->variables.character_set_client= cs_save; /* Imagine the thread had created a temp table, then was doing a SELECT, and the SELECT was killed. Then it's not clever to mark the statement above as "killed", because it's not really a statement updating data, and there are 99.99% chances it will succeed on slave. If a real update (one updating a persistent table) was killed on the master, then this real update will be logged with error_code=killed, rightfully causing the slave to stop. */ qinfo.error_code= 0; mysql_bin_log.write(&qinfo); thd->variables.pseudo_thread_id= save_pseudo_thread_id; } else { next= table->next; close_temporary(table, 1, 1); } } if (!was_quote_show) thd->options&= ~OPTION_QUOTE_SHOW_CREATE; /* restore option */ thd->temporary_tables=0; } /* Find table in list. SYNOPSIS find_table_in_list() table Pointer to table list offset Offset to which list in table structure to use db_name Data base name table_name Table name NOTES: This is called by find_table_in_local_list() and find_table_in_global_list(). RETURN VALUES NULL Table not found # Pointer to found table. */ TABLE_LIST *find_table_in_list(TABLE_LIST *table, TABLE_LIST *TABLE_LIST::*link, const char *db_name, const char *table_name) { for (; table; table= table->*link ) { if ((table->table == 0 || table->table->s->tmp_table == NO_TMP_TABLE) && strcmp(table->db, db_name) == 0 && strcmp(table->table_name, table_name) == 0) break; } return table; } /* Test that table is unique (It's only exists once in the table list) SYNOPSIS unique_table() thd thread handle table table which should be checked table_list list of tables check_alias whether to check tables' aliases NOTE: to exclude derived tables from check we use following mechanism: a) during derived table processing set THD::derived_tables_processing b) JOIN::prepare set SELECT::exclude_from_table_unique_test if THD::derived_tables_processing set. (we can't use JOIN::execute because for PS we perform only JOIN::prepare, but we can't set this flag in JOIN::prepare if we are not sure that we are in derived table processing loop, because multi-update call fix_fields() for some its items (which mean JOIN::prepare for subqueries) before unique_table call to detect which tables should be locked for write). c) unique_table skip all tables which belong to SELECT with SELECT::exclude_from_table_unique_test set. Also SELECT::exclude_from_table_unique_test used to exclude from check tables of main SELECT of multi-delete and multi-update We also skip tables with TABLE_LIST::prelocking_placeholder set, because we want to allow SELECTs from them, and their modification will rise the error anyway. TODO: when we will have table/view change detection we can do this check only once for PS/SP RETURN found duplicate 0 if table is unique */ TABLE_LIST* unique_table(THD *thd, TABLE_LIST *table, TABLE_LIST *table_list, bool check_alias) { TABLE_LIST *res; const char *d_name, *t_name, *t_alias; DBUG_ENTER("unique_table"); DBUG_PRINT("enter", ("table alias: %s", table->alias)); /* If this function called for query which update table (INSERT/UPDATE/...) then we have in table->table pointer to TABLE object which we are updating even if it is VIEW so we need TABLE_LIST of this TABLE object to get right names (even if lower_case_table_names used). If this function called for CREATE command that we have not opened table (table->table equal to 0) and right names is in current TABLE_LIST object. */ if (table->table) { /* temporary table is always unique */ if (table->table && table->table->s->tmp_table != NO_TMP_TABLE) DBUG_RETURN(0); table= table->find_underlying_table(table->table); /* as far as we have table->table we have to find real TABLE_LIST of it in underlying tables */ DBUG_ASSERT(table); } d_name= table->db; t_name= table->table_name; t_alias= table->alias; DBUG_PRINT("info", ("real table: %s.%s", d_name, t_name)); for (;;) { if (((! (res= find_table_in_global_list(table_list, d_name, t_name))) && (! (res= mysql_lock_have_duplicate(thd, table, table_list)))) || ((!res->table || res->table != table->table) && (!check_alias || !(lower_case_table_names ? my_strcasecmp(files_charset_info, t_alias, res->alias) : strcmp(t_alias, res->alias))) && res->select_lex && !res->select_lex->exclude_from_table_unique_test && !res->prelocking_placeholder)) break; /* If we found entry of this table or table of SELECT which already processed in derived table or top select of multi-update/multi-delete (exclude_from_table_unique_test) or prelocking placeholder. */ table_list= res->next_global; DBUG_PRINT("info", ("found same copy of table or table which we should skip")); } DBUG_RETURN(res); } /* Issue correct error message in case we found 2 duplicate tables which prevent some update operation SYNOPSIS update_non_unique_table_error() update table which we try to update operation name of update operation duplicate duplicate table which we found NOTE: here we hide view underlying tables if we have them */ void update_non_unique_table_error(TABLE_LIST *update, const char *operation, TABLE_LIST *duplicate) { update= update->top_table(); duplicate= duplicate->top_table(); if (!update->view || !duplicate->view || update->view == duplicate->view || update->view_name.length != duplicate->view_name.length || update->view_db.length != duplicate->view_db.length || my_strcasecmp(table_alias_charset, update->view_name.str, duplicate->view_name.str) != 0 || my_strcasecmp(table_alias_charset, update->view_db.str, duplicate->view_db.str) != 0) { /* it is not the same view repeated (but it can be parts of the same copy of view), so we have to hide underlying tables. */ if (update->view) { /* Issue the ER_NON_INSERTABLE_TABLE error for an INSERT */ if (update->view == duplicate->view) my_error(!strncmp(operation, "INSERT", 6) ? ER_NON_INSERTABLE_TABLE : ER_NON_UPDATABLE_TABLE, MYF(0), update->alias, operation); else my_error(ER_VIEW_PREVENT_UPDATE, MYF(0), (duplicate->view ? duplicate->alias : update->alias), operation, update->alias); return; } if (duplicate->view) { my_error(ER_VIEW_PREVENT_UPDATE, MYF(0), duplicate->alias, operation, update->alias); return; } } my_error(ER_UPDATE_TABLE_USED, MYF(0), update->alias); } TABLE *find_temporary_table(THD *thd, const char *db, const char *table_name) { TABLE_LIST table_list; table_list.db= (char*) db; table_list.table_name= (char*) table_name; return find_temporary_table(thd, &table_list); } TABLE *find_temporary_table(THD *thd, TABLE_LIST *table_list) { char key[MAX_DBKEY_LENGTH]; uint key_length; TABLE *table; DBUG_ENTER("find_temporary_table"); DBUG_PRINT("enter", ("table: '%s'.'%s'", table_list->db, table_list->table_name)); key_length= create_table_def_key(thd, key, table_list, 1); for (table=thd->temporary_tables ; table ; table= table->next) { if (table->s->table_cache_key.length == key_length && !memcmp(table->s->table_cache_key.str, key, key_length)) { DBUG_PRINT("info", ("Found table. server_id: %u pseudo_thread_id: %lu", (uint) thd->server_id, (ulong) thd->variables.pseudo_thread_id)); DBUG_RETURN(table); } } DBUG_RETURN(0); // Not a temporary table } /** Drop a temporary table. Try to locate the table in the list of thd->temporary_tables. If the table is found: - if the table is being used by some outer statement, fail. - if the table is in thd->locked_tables, unlock it and remove it from the list of locked tables. Currently only transactional temporary tables are present in the locked_tables list. - Close the temporary table, remove its .FRM - remove the table from the list of temporary tables This function is used to drop user temporary tables, as well as internal tables created in CREATE TEMPORARY TABLE ... SELECT or ALTER TABLE. Even though part of the work done by this function is redundant when the table is internal, as long as we link both internal and user temporary tables into the same thd->temporary_tables list, it's impossible to tell here whether we're dealing with an internal or a user temporary table. @retval 0 the table was found and dropped successfully. @retval 1 the table was not found in the list of temporary tables of this thread @retval -1 the table is in use by a outer query */ int drop_temporary_table(THD *thd, TABLE_LIST *table_list) { TABLE *table; DBUG_ENTER("drop_temporary_table"); DBUG_PRINT("tmptable", ("closing table: '%s'.'%s'", table_list->db, table_list->table_name)); if (!(table= find_temporary_table(thd, table_list))) DBUG_RETURN(1); /* Table might be in use by some outer statement. */ if (table->query_id && table->query_id != thd->query_id) { my_error(ER_CANT_REOPEN_TABLE, MYF(0), table->alias); DBUG_RETURN(-1); } /* If LOCK TABLES list is not empty and contains this table, unlock the table and remove the table from this list. */ mysql_lock_remove(thd, thd->locked_tables, table, FALSE); close_temporary_table(thd, table, 1, 1); DBUG_RETURN(0); } /* unlink from thd->temporary tables and close temporary table */ void close_temporary_table(THD *thd, TABLE *table, bool free_share, bool delete_table) { DBUG_ENTER("close_temporary_table"); DBUG_PRINT("tmptable", ("closing table: '%s'.'%s' 0x%lx alias: '%s'", table->s->db.str, table->s->table_name.str, (long) table, table->alias)); /* When closing a MERGE parent or child table, detach the children first. Clear child table references as MERGE table cannot be reopened after final close of one of its tables. This is necessary here because it is sometimes called with attached tables and without prior close_thread_tables(). E.g. in mysql_alter_table(), mysql_rm_table_part2(), mysql_truncate(), drop_open_table(). */ if (table->child_l || table->parent) detach_merge_children(table, TRUE); if (table->prev) { table->prev->next= table->next; if (table->prev->next) table->next->prev= table->prev; } else { /* removing the item from the list */ DBUG_ASSERT(table == thd->temporary_tables); /* slave must reset its temporary list pointer to zero to exclude passing non-zero value to end_slave via rli->save_temporary_tables when no temp tables opened, see an invariant below. */ thd->temporary_tables= table->next; if (thd->temporary_tables) table->next->prev= 0; } if (thd->slave_thread) { /* natural invariant of temporary_tables */ DBUG_ASSERT(slave_open_temp_tables || !thd->temporary_tables); slave_open_temp_tables--; } close_temporary(table, free_share, delete_table); DBUG_VOID_RETURN; } /* Close and delete a temporary table NOTE This dosn't unlink table from thd->temporary If this is needed, use close_temporary_table() */ void close_temporary(TABLE *table, bool free_share, bool delete_table) { handlerton *table_type= table->s->db_type(); DBUG_ENTER("close_temporary"); DBUG_PRINT("tmptable", ("closing table: '%s'.'%s'", table->s->db.str, table->s->table_name.str)); free_io_cache(table); closefrm(table, 0); if (delete_table) rm_temporary_table(table_type, table->s->path.str); if (free_share) { free_table_share(table->s); my_free((char*) table,MYF(0)); } DBUG_VOID_RETURN; } /* Used by ALTER TABLE when the table is a temporary one. It changes something only if the ALTER contained a RENAME clause (otherwise, table_name is the old name). Prepares a table cache key, which is the concatenation of db, table_name and thd->slave_proxy_id, separated by '\0'. */ bool rename_temporary_table(THD* thd, TABLE *table, const char *db, const char *table_name) { char *key; uint key_length; TABLE_SHARE *share= table->s; TABLE_LIST table_list; DBUG_ENTER("rename_temporary_table"); if (!(key=(char*) alloc_root(&share->mem_root, MAX_DBKEY_LENGTH))) DBUG_RETURN(1); /* purecov: inspected */ table_list.db= (char*) db; table_list.table_name= (char*) table_name; key_length= create_table_def_key(thd, key, &table_list, 1); share->set_table_cache_key(key, key_length); DBUG_RETURN(0); } /* move table first in unused links */ static void relink_unused(TABLE *table) { /* Assert that MERGE children are not attached in unused_tables. */ DBUG_ASSERT(!table->is_children_attached()); if (table != unused_tables) { table->prev->next=table->next; /* Remove from unused list */ table->next->prev=table->prev; table->next=unused_tables; /* Link in unused tables */ table->prev=unused_tables->prev; unused_tables->prev->next=table; unused_tables->prev=table; unused_tables=table; check_unused(); } } /** Prepare an open merge table for close. @param[in] thd thread context @param[in] table table to prepare @param[in,out] prev_pp pointer to pointer of previous table @detail If the table is a MERGE parent, just detach the children. If the table is a MERGE child, close the parent (incl. detach). */ static void unlink_open_merge(THD *thd, TABLE *table, TABLE ***prev_pp) { DBUG_ENTER("unlink_open_merge"); if (table->parent) { /* If MERGE child, close parent too. Closing includes detaching. This is used for example in ALTER TABLE t1 RENAME TO t5 under LOCK TABLES where t1 is a MERGE child: CREATE TABLE t1 (c1 INT); CREATE TABLE t2 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1); LOCK TABLES t1 WRITE, t2 WRITE; ALTER TABLE t1 RENAME TO t5; */ TABLE *parent= table->parent; TABLE **prv_p; /* Find parent in open_tables list. */ for (prv_p= &thd->open_tables; *prv_p && (*prv_p != parent); prv_p= &(*prv_p)->next) {} if (*prv_p) { /* Special treatment required if child follows parent in list. */ if (*prev_pp == &parent->next) *prev_pp= prv_p; /* Remove parent from open_tables list and close it. This includes detaching and hence clearing parent references. */ close_thread_table(thd, prv_p); } } else if (table->child_l) { /* When closing a MERGE parent, detach the children first. It is not necessary to clear the child or parent table reference of this table because the TABLE is freed. But we need to clear the child or parent references of the other belonging tables so that they cannot be moved into the unused_tables chain with these pointers set. This is used for example in ALTER TABLE t2 RENAME TO t5 under LOCK TABLES where t2 is a MERGE parent: CREATE TABLE t1 (c1 INT); CREATE TABLE t2 (c1 INT) ENGINE=MRG_MYISAM UNION=(t1); LOCK TABLES t1 WRITE, t2 WRITE; ALTER TABLE t2 RENAME TO t5; */ detach_merge_children(table, TRUE); } DBUG_VOID_RETURN; } /** Remove all instances of table from thread's open list and table cache. @param thd Thread context @param find Table to remove @param unlock TRUE - free all locks on tables removed that are done with LOCK TABLES FALSE - otherwise @note When unlock parameter is FALSE or current thread doesn't have any tables locked with LOCK TABLES, tables are assumed to be not locked (for example already unlocked). */ void unlink_open_table(THD *thd, TABLE *find, bool unlock) { char key[MAX_DBKEY_LENGTH]; uint key_length= find->s->table_cache_key.length; TABLE *list, **prev; DBUG_ENTER("unlink_open_table"); safe_mutex_assert_owner(&LOCK_open); memcpy(key, find->s->table_cache_key.str, key_length); /* Note that we need to hold LOCK_open while changing the open_tables list. Another thread may work on it. (See: remove_table_from_cache(), mysql_wait_completed_table()) Closing a MERGE child before the parent would be fatal if the other thread tries to abort the MERGE lock in between. */ for (prev= &thd->open_tables; *prev; ) { list= *prev; if (list->s->table_cache_key.length == key_length && !memcmp(list->s->table_cache_key.str, key, key_length)) { if (unlock && thd->locked_tables) mysql_lock_remove(thd, thd->locked_tables, list->parent ? list->parent : list, TRUE); /* Prepare MERGE table for close. Close parent if necessary. */ unlink_open_merge(thd, list, &prev); /* Remove table from open_tables list. */ *prev= list->next; /* Close table. */ VOID(hash_delete(&open_cache,(uchar*) list)); // Close table } else { /* Step to next entry in open_tables list. */ prev= &list->next; } } // Notify any 'refresh' threads broadcast_refresh(); DBUG_VOID_RETURN; } /** Auxiliary routine which closes and drops open table. @param thd Thread handle @param table TABLE object for table to be dropped @param db_name Name of database for this table @param table_name Name of this table @note This routine assumes that table to be closed is open only by calling thread so we needn't wait until other threads will close the table. Also unless called under implicit or explicit LOCK TABLES mode it assumes that table to be dropped is already unlocked. In the former case it will also remove lock on the table. But one should not rely on this behaviour as it may change in future. Currently, however, this function is never called for a table that was locked with LOCK TABLES. */ void drop_open_table(THD *thd, TABLE *table, const char *db_name, const char *table_name) { if (table->s->tmp_table) close_temporary_table(thd, table, 1, 1); else { handlerton *table_type= table->s->db_type(); VOID(pthread_mutex_lock(&LOCK_open)); /* unlink_open_table() also tells threads waiting for refresh or close that something has happened. */ unlink_open_table(thd, table, FALSE); quick_rm_table(table_type, db_name, table_name, 0); VOID(pthread_mutex_unlock(&LOCK_open)); } } /* Wait for condition but allow the user to send a kill to mysqld SYNOPSIS wait_for_condition() thd Thread handler mutex mutex that is currently hold that is associated with condition Will be unlocked on return cond Condition to wait for */ void wait_for_condition(THD *thd, pthread_mutex_t *mutex, pthread_cond_t *cond) { /* Wait until the current table is up to date */ const char *proc_info; thd->mysys_var->current_mutex= mutex; thd->mysys_var->current_cond= cond; proc_info=thd->proc_info; thd_proc_info(thd, "Waiting for table"); DBUG_ENTER("wait_for_condition"); if (!thd->killed) (void) pthread_cond_wait(cond, mutex); /* We must unlock mutex first to avoid deadlock becasue conditions are sent to this thread by doing locks in the following order: lock(mysys_var->mutex) lock(mysys_var->current_mutex) One by effect of this that one can only use wait_for_condition with condition variables that are guranteed to not disapper (freed) even if this mutex is unlocked */ pthread_mutex_unlock(mutex); pthread_mutex_lock(&thd->mysys_var->mutex); thd->mysys_var->current_mutex= 0; thd->mysys_var->current_cond= 0; thd_proc_info(thd, proc_info); pthread_mutex_unlock(&thd->mysys_var->mutex); DBUG_VOID_RETURN; } /** Exclusively name-lock a table that is already write-locked by the current thread. @param thd current thread context @param tables table list containing one table to open. @return FALSE on success, TRUE otherwise. */ bool name_lock_locked_table(THD *thd, TABLE_LIST *tables) { DBUG_ENTER("name_lock_locked_table"); /* Under LOCK TABLES we must only accept write locked tables. */ tables->table= find_locked_table(thd, tables->db, tables->table_name); if (!tables->table) my_error(ER_TABLE_NOT_LOCKED, MYF(0), tables->alias); else if (tables->table->reginfo.lock_type < TL_WRITE_LOW_PRIORITY) my_error(ER_TABLE_NOT_LOCKED_FOR_WRITE, MYF(0), tables->alias); else { /* Ensures that table is opened only by this thread and that no other statement will open this table. */ wait_while_table_is_used(thd, tables->table, HA_EXTRA_FORCE_REOPEN); DBUG_RETURN(FALSE); } DBUG_RETURN(TRUE); } /* Open table which is already name-locked by this thread. SYNOPSIS reopen_name_locked_table() thd Thread handle table_list TABLE_LIST object for table to be open, TABLE_LIST::table member should point to TABLE object which was used for name-locking. link_in TRUE - if TABLE object for table to be opened should be linked into THD::open_tables list. FALSE - placeholder used for name-locking is already in this list so we only need to preserve TABLE::next pointer. NOTE This function assumes that its caller already acquired LOCK_open mutex. RETURN VALUE FALSE - Success TRUE - Error */ bool reopen_name_locked_table(THD* thd, TABLE_LIST* table_list, bool link_in) { TABLE *table= table_list->table; TABLE_SHARE *share; char *table_name= table_list->table_name; TABLE orig_table; DBUG_ENTER("reopen_name_locked_table"); safe_mutex_assert_owner(&LOCK_open); if (thd->killed || !table) DBUG_RETURN(TRUE); orig_table= *table; if (open_unireg_entry(thd, table, table_list, table_name, table->s->table_cache_key.str, table->s->table_cache_key.length, thd->mem_root, 0)) { intern_close_table(table); /* If there was an error during opening of table (for example if it does not exist) '*table' object can be wiped out. To be able properly release name-lock in this case we should restore this object to its original state. */ *table= orig_table; DBUG_RETURN(TRUE); } share= table->s; /* We want to prevent other connections from opening this table until end of statement as it is likely that modifications of table's metadata are not yet finished (for example CREATE TRIGGER have to change .TRG file, or we might want to drop table if CREATE TABLE ... SELECT fails). This also allows us to assume that no other connection will sneak in before we will get table-level lock on this table. */ share->version=0; table->in_use = thd; check_unused(); if (link_in) { table->next= thd->open_tables; thd->open_tables= table; } else { /* TABLE object should be already in THD::open_tables list so we just need to set TABLE::next correctly. */ table->next= orig_table.next; } table->tablenr=thd->current_tablenr++; table->used_fields=0; table->const_table=0; table->null_row= table->maybe_null= table->force_index= 0; table->status=STATUS_NO_RECORD; DBUG_RETURN(FALSE); } /** Create and insert into table cache placeholder for table which will prevent its opening (or creation) (a.k.a lock table name). @param thd Thread context @param key Table cache key for name to be locked @param key_length Table cache key length @return Pointer to TABLE object used for name locking or 0 in case of failure. */ TABLE *table_cache_insert_placeholder(THD *thd, const char *key, uint key_length) { TABLE *table; TABLE_SHARE *share; char *key_buff; DBUG_ENTER("table_cache_insert_placeholder"); safe_mutex_assert_owner(&LOCK_open); /* Create a table entry with the right key and with an old refresh version Note that we must use my_multi_malloc() here as this is freed by the table cache */ if (!my_multi_malloc(MYF(MY_WME | MY_ZEROFILL), &table, sizeof(*table), &share, sizeof(*share), &key_buff, key_length, NULL)) DBUG_RETURN(NULL); table->s= share; share->set_table_cache_key(key_buff, key, key_length); share->tmp_table= INTERNAL_TMP_TABLE; // for intern_close_table table->in_use= thd; table->locked_by_name=1; if (my_hash_insert(&open_cache, (uchar*)table)) { my_free((uchar*) table, MYF(0)); DBUG_RETURN(NULL); } DBUG_RETURN(table); } /** Obtain an exclusive name lock on the table if it is not cached in the table cache. @param thd Thread context @param db Name of database @param table_name Name of table @param[out] table Out parameter which is either: - set to NULL if table cache contains record for the table or - set to point to the TABLE instance used for name-locking. @note This function takes into account all records for table in table cache, even placeholders used for name-locking. This means that 'table' parameter can be set to NULL for some situations when table does not really exist. @retval TRUE Error occured (OOM) @retval FALSE Success. 'table' parameter set according to above rules. */ bool lock_table_name_if_not_cached(THD *thd, const char *db, const char *table_name, TABLE **table) { char key[MAX_DBKEY_LENGTH]; uint key_length; DBUG_ENTER("lock_table_name_if_not_cached"); key_length= (uint)(strmov(strmov(key, db) + 1, table_name) - key) + 1; VOID(pthread_mutex_lock(&LOCK_open)); if (hash_search(&open_cache, (uchar *)key, key_length)) { VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_PRINT("info", ("Table is cached, name-lock is not obtained")); *table= 0; DBUG_RETURN(FALSE); } if (!(*table= table_cache_insert_placeholder(thd, key, key_length))) { VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(TRUE); } (*table)->open_placeholder= 1; (*table)->next= thd->open_tables; thd->open_tables= *table; VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(FALSE); } /** Check that table exists in table definition cache, on disk or in some storage engine. @param thd Thread context @param table Table list element @param[out] exists Out parameter which is set to TRUE if table exists and to FALSE otherwise. @note This function assumes that caller owns LOCK_open mutex. It also assumes that the fact that there are no name-locks on the table was checked beforehand. @note If there is no .FRM file for the table but it exists in one of engines (e.g. it was created on another node of NDB cluster) this function will fetch and create proper .FRM file for it. @retval TRUE Some error occured @retval FALSE No error. 'exists' out parameter set accordingly. */ bool check_if_table_exists(THD *thd, TABLE_LIST *table, bool *exists) { char path[FN_REFLEN]; int rc; DBUG_ENTER("check_if_table_exists"); safe_mutex_assert_owner(&LOCK_open); *exists= TRUE; if (get_cached_table_share(table->db, table->table_name)) DBUG_RETURN(FALSE); build_table_filename(path, sizeof(path) - 1, table->db, table->table_name, reg_ext, 0); if (!access(path, F_OK)) DBUG_RETURN(FALSE); /* .FRM file doesn't exist. Check if some engine can provide it. */ rc= ha_create_table_from_engine(thd, table->db, table->table_name); if (rc < 0) { /* Table does not exists in engines as well. */ *exists= FALSE; DBUG_RETURN(FALSE); } else if (!rc) { /* Table exists in some engine and .FRM for it was created. */ DBUG_RETURN(FALSE); } else /* (rc > 0) */ { my_printf_error(ER_UNKNOWN_ERROR, "Failed to open '%-.64s', error while " "unpacking from engine", MYF(0), table->table_name); DBUG_RETURN(TRUE); } } /* Open a table. SYNOPSIS open_table() thd Thread context. table_list Open first table in list. refresh INOUT Pointer to memory that will be set to 1 if we need to close all tables and reopen them. If this is a NULL pointer, then the table is not put in the thread-open-list. flags Bitmap of flags to modify how open works: MYSQL_LOCK_IGNORE_FLUSH - Open table even if someone has done a flush or namelock on it. No version number checking is done. MYSQL_OPEN_TEMPORARY_ONLY - Open only temporary table not the base table or view. IMPLEMENTATION Uses a cache of open tables to find a table not in use. If table list element for the table to be opened has "create" flag set and table does not exist, this function will automatically insert a placeholder for exclusive name lock into the open tables cache and will return the TABLE instance that corresponds to this placeholder. RETURN NULL Open failed. If refresh is set then one should close all other tables and retry the open. # Success. Pointer to TABLE object for open table. */ TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT *mem_root, bool *refresh, uint flags) { reg1 TABLE *table; char key[MAX_DBKEY_LENGTH]; uint key_length; char *alias= table_list->alias; HASH_SEARCH_STATE state; DBUG_ENTER("open_table"); /* Parsing of partitioning information from .frm needs thd->lex set up. */ DBUG_ASSERT(thd->lex->is_lex_started); /* find a unused table in the open table cache */ if (refresh) *refresh=0; /* an open table operation needs a lot of the stack space */ if (check_stack_overrun(thd, STACK_MIN_SIZE_FOR_OPEN, (uchar *)&alias)) DBUG_RETURN(0); if (thd->killed) DBUG_RETURN(0); key_length= (create_table_def_key(thd, key, table_list, 1) - TMP_TABLE_KEY_EXTRA); /* Unless requested otherwise, try to resolve this table in the list of temporary tables of this thread. In MySQL temporary tables are always thread-local and "shadow" possible base tables with the same name. This block implements the behaviour. TODO: move this block into a separate function. */ if (!table_list->skip_temporary) { for (table= thd->temporary_tables; table ; table=table->next) { if (table->s->table_cache_key.length == key_length + TMP_TABLE_KEY_EXTRA && !memcmp(table->s->table_cache_key.str, key, key_length + TMP_TABLE_KEY_EXTRA)) { /* We're trying to use the same temporary table twice in a query. Right now we don't support this because a temporary table is always represented by only one TABLE object in THD, and it can not be cloned. Emit an error for an unsupported behaviour. */ if (table->query_id) { DBUG_PRINT("error", ("query_id: %lu server_id: %u pseudo_thread_id: %lu", (ulong) table->query_id, (uint) thd->server_id, (ulong) thd->variables.pseudo_thread_id)); my_error(ER_CANT_REOPEN_TABLE, MYF(0), table->alias); DBUG_RETURN(0); } table->query_id= thd->query_id; thd->thread_specific_used= TRUE; DBUG_PRINT("info",("Using temporary table")); goto reset; } } } if (flags & MYSQL_OPEN_TEMPORARY_ONLY) { my_error(ER_NO_SUCH_TABLE, MYF(0), table_list->db, table_list->table_name); DBUG_RETURN(0); } /* The table is not temporary - if we're in pre-locked or LOCK TABLES mode, let's try to find the requested table in the list of pre-opened and locked tables. If the table is not there, return an error - we can't open not pre-opened tables in pre-locked/LOCK TABLES mode. TODO: move this block into a separate function. */ if (thd->locked_tables || thd->prelocked_mode) { // Using table locks TABLE *best_table= 0; int best_distance= INT_MIN; bool check_if_used= thd->prelocked_mode && ((int) table_list->lock_type >= (int) TL_WRITE_ALLOW_WRITE); for (table=thd->open_tables; table ; table=table->next) { if (table->s->table_cache_key.length == key_length && !memcmp(table->s->table_cache_key.str, key, key_length)) { if (check_if_used && table->query_id && table->query_id != thd->query_id) { /* If we are in stored function or trigger we should ensure that we won't change table that is already used by calling statement. So if we are opening table for writing, we should check that it is not already open by some calling stamement. */ my_error(ER_CANT_UPDATE_USED_TABLE_IN_SF_OR_TRG, MYF(0), table->s->table_name.str); DBUG_RETURN(0); } /* When looking for a usable TABLE, ignore MERGE children, as they belong to their parent and cannot be used explicitly. */ if (!my_strcasecmp(system_charset_info, table->alias, alias) && table->query_id != thd->query_id && /* skip tables already used */ !(thd->prelocked_mode && table->query_id) && !table->parent) { int distance= ((int) table->reginfo.lock_type - (int) table_list->lock_type); /* Find a table that either has the exact lock type requested, or has the best suitable lock. In case there is no locked table that has an equal or higher lock than requested, we us the closest matching lock to be able to produce an error message about wrong lock mode on the table. The best_table is changed if bd < 0 <= d or bd < d < 0 or 0 <= d < bd. distance < 0 - No suitable lock found distance > 0 - we have lock mode higher then we require distance == 0 - we have lock mode exactly which we need */ if (best_distance < 0 && distance > best_distance || distance >= 0 && distance < best_distance) { best_distance= distance; best_table= table; if (best_distance == 0 && !check_if_used) { /* If we have found perfect match and we don't need to check that table is not used by one of calling statements (assuming that we are inside of function or trigger) we can finish iterating through open tables list. */ break; } } } } } if (best_table) { table= best_table; table->query_id= thd->query_id; DBUG_PRINT("info",("Using locked table")); goto reset; } /* Is this table a view and not a base table? (it is work around to allow to open view with locked tables, real fix will be made after definition cache will be made) */ { char path[FN_REFLEN]; enum legacy_db_type not_used; build_table_filename(path, sizeof(path) - 1, table_list->db, table_list->table_name, reg_ext, 0); if (mysql_frm_type(thd, path, ¬_used) == FRMTYPE_VIEW) { /* Will not be used (because it's VIEW) but has to be passed. Also we will not free it (because it is a stack variable). */ TABLE tab; table= &tab; VOID(pthread_mutex_lock(&LOCK_open)); if (!open_unireg_entry(thd, table, table_list, alias, key, key_length, mem_root, 0)) { DBUG_ASSERT(table_list->view != 0); VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(0); // VIEW } VOID(pthread_mutex_unlock(&LOCK_open)); } } /* No table in the locked tables list. In case of explicit LOCK TABLES this can happen if a user did not include the able into the list. In case of pre-locked mode locked tables list is generated automatically, so we may only end up here if the table did not exist when locked tables list was created. */ if (thd->prelocked_mode == PRELOCKED) my_error(ER_NO_SUCH_TABLE, MYF(0), table_list->db, table_list->alias); else my_error(ER_TABLE_NOT_LOCKED, MYF(0), alias); DBUG_RETURN(0); } /* Non pre-locked/LOCK TABLES mode, and the table is not temporary: this is the normal use case. Now we should: - try to find the table in the table cache. - if one of the discovered TABLE instances is name-locked (table->s->version == 0) or some thread has started FLUSH TABLES (refresh_version > table->s->version), back off -- we have to wait until no one holds a name lock on the table. - if there is no such TABLE in the name cache, read the table definition and insert it into the cache. We perform all of the above under LOCK_open which currently protects the open cache (also known as table cache) and table definitions stored on disk. */ VOID(pthread_mutex_lock(&LOCK_open)); /* If it's the first table from a list of tables used in a query, remember refresh_version (the version of open_cache state). If the version changes while we're opening the remaining tables, we will have to back off, close all the tables opened-so-far, and try to reopen them. Note: refresh_version is currently changed only during FLUSH TABLES. */ if (!thd->open_tables) thd->version=refresh_version; else if ((thd->version != refresh_version) && ! (flags & MYSQL_LOCK_IGNORE_FLUSH)) { /* Someone did a refresh while thread was opening tables */ if (refresh) *refresh=1; VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(0); } /* In order for the back off and re-start process to work properly, handler tables having old versions (due to FLUSH TABLES or pending name-lock) MUST be closed. This is specially important if a name-lock is pending for any table of the handler_tables list, otherwise a deadlock may occur. */ if (thd->handler_tables) mysql_ha_flush(thd); /* Actually try to find the table in the open_cache. The cache may contain several "TABLE" instances for the same physical table. The instances that are currently "in use" by some thread have their "in_use" member != NULL. There is no good reason for having more than one entry in the hash for the same physical table, except that we use this as an implicit "pending locks queue" - see wait_for_locked_table_names for details. */ for (table= (TABLE*) hash_first(&open_cache, (uchar*) key, key_length, &state); table && table->in_use ; table= (TABLE*) hash_next(&open_cache, (uchar*) key, key_length, &state)) { DBUG_PRINT("tcache", ("in_use table: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); /* Here we flush tables marked for flush. Normally, table->s->version contains the value of refresh_version from the moment when this table was (re-)opened and added to the cache. If since then we did (or just started) FLUSH TABLES statement, refresh_version has been increased. For "name-locked" TABLE instances, table->s->version is set to 0 (see lock_table_name for details). In case there is a pending FLUSH TABLES or a name lock, we need to back off and re-start opening tables. If we do not back off now, we may dead lock in case of lock order mismatch with some other thread: c1: name lock t1; -- sort of exclusive lock c2: open t2; -- sort of shared lock c1: name lock t2; -- blocks c2: open t1; -- blocks */ if (table->needs_reopen_or_name_lock()) { DBUG_PRINT("note", ("Found table '%s.%s' with different refresh version", table_list->db, table_list->table_name)); if (flags & MYSQL_LOCK_IGNORE_FLUSH) { /* Force close at once after usage */ thd->version= table->s->version; continue; } /* Avoid self-deadlocks by detecting self-dependencies. */ if (table->open_placeholder && table->in_use == thd) { VOID(pthread_mutex_unlock(&LOCK_open)); my_error(ER_UPDATE_TABLE_USED, MYF(0), table->s->table_name.str); DBUG_RETURN(0); } /* Back off, part 1: mark the table as "unused" for the purpose of name-locking by setting table->db_stat to 0. Do that only for the tables in this thread that have an old table->s->version (this is an optimization (?)). table->db_stat == 0 signals wait_for_locked_table_names that the tables in question are not used any more. See table_is_used call for details. Notice that HANDLER tables were already taken care of by the earlier call to mysql_ha_flush() in this same critical section. */ close_old_data_files(thd,thd->open_tables,0,0); /* Back-off part 2: try to avoid "busy waiting" on the table: if the table is in use by some other thread, we suspend and wait till the operation is complete: when any operation that juggles with table->s->version completes, it broadcasts COND_refresh condition variable. If 'old' table we met is in use by current thread we return without waiting since in this situation it's this thread which is responsible for broadcasting on COND_refresh (and this was done already in close_old_data_files()). Good example of such situation is when we have statement that needs two instances of table and FLUSH TABLES comes after we open first instance but before we open second instance. */ if (table->in_use != thd) { /* wait_for_conditionwill unlock LOCK_open for us */ wait_for_condition(thd, &LOCK_open, &COND_refresh); } else { VOID(pthread_mutex_unlock(&LOCK_open)); } /* There is a refresh in progress for this table. Signal the caller that it has to try again. */ if (refresh) *refresh=1; DBUG_RETURN(0); } } if (table) { DBUG_PRINT("tcache", ("unused table: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); /* Unlink the table from "unused_tables" list. */ if (table == unused_tables) { // First unused unused_tables=unused_tables->next; // Remove from link if (table == unused_tables) unused_tables=0; } table->prev->next=table->next; /* Remove from unused list */ table->next->prev=table->prev; table->in_use= thd; } else { /* Insert a new TABLE instance into the open cache */ int error; DBUG_PRINT("tcache", ("opening new table")); /* Free cache if too big */ while (open_cache.records > table_cache_size && unused_tables) VOID(hash_delete(&open_cache,(uchar*) unused_tables)); /* purecov: tested */ if (table_list->create) { bool exists; if (check_if_table_exists(thd, table_list, &exists)) { VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(NULL); } if (!exists) { /* Table to be created, so we need to create placeholder in table-cache. */ if (!(table= table_cache_insert_placeholder(thd, key, key_length))) { VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(NULL); } /* Link placeholder to the open tables list so it will be automatically removed once tables are closed. Also mark it so it won't be ignored by other trying to take name-lock. */ table->open_placeholder= 1; table->next= thd->open_tables; thd->open_tables= table; VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(table); } /* Table exists. Let us try to open it. */ } /* make a new table */ if (!(table=(TABLE*) my_malloc(sizeof(*table),MYF(MY_WME)))) { VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(NULL); } error= open_unireg_entry(thd, table, table_list, alias, key, key_length, mem_root, (flags & OPEN_VIEW_NO_PARSE)); if (error > 0) { my_free((uchar*)table, MYF(0)); VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(NULL); } if (table_list->view || error < 0) { /* VIEW not really opened, only frm were read. Set 1 as a flag here */ if (error < 0) table_list->view= (st_lex*)1; my_free((uchar*)table, MYF(0)); VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(0); // VIEW } DBUG_PRINT("info", ("inserting table '%s'.'%s' 0x%lx into the cache", table->s->db.str, table->s->table_name.str, (long) table)); VOID(my_hash_insert(&open_cache,(uchar*) table)); } check_unused(); // Debugging call VOID(pthread_mutex_unlock(&LOCK_open)); if (refresh) { table->next=thd->open_tables; /* Link into simple list */ thd->open_tables=table; } table->reginfo.lock_type=TL_READ; /* Assume read */ reset: DBUG_ASSERT(table->s->ref_count > 0 || table->s->tmp_table != NO_TMP_TABLE); if (thd->lex->need_correct_ident()) table->alias_name_used= my_strcasecmp(table_alias_charset, table->s->table_name.str, alias); /* Fix alias if table name changes */ if (strcmp(table->alias, alias)) { uint length=(uint) strlen(alias)+1; table->alias= (char*) my_realloc((char*) table->alias, length, MYF(MY_WME)); memcpy((char*) table->alias, alias, length); } /* These variables are also set in reopen_table() */ table->tablenr=thd->current_tablenr++; table->used_fields=0; table->const_table=0; table->null_row= table->maybe_null= table->force_index= 0; table->status=STATUS_NO_RECORD; table->insert_values= 0; table->fulltext_searched= 0; table->file->ft_handler= 0; /* Catch wrong handling of the auto_increment_field_not_null. */ DBUG_ASSERT(!table->auto_increment_field_not_null); table->auto_increment_field_not_null= FALSE; if (table->timestamp_field) table->timestamp_field_type= table->timestamp_field->get_auto_set_type(); table->pos_in_table_list= table_list; table_list->updatable= 1; // It is not derived table nor non-updatable VIEW table->clear_column_bitmaps(); DBUG_ASSERT(table->key_read == 0); DBUG_RETURN(table); } TABLE *find_locked_table(THD *thd, const char *db,const char *table_name) { char key[MAX_DBKEY_LENGTH]; uint key_length=(uint) (strmov(strmov(key,db)+1,table_name)-key)+1; for (TABLE *table=thd->open_tables; table ; table=table->next) { if (table->s->table_cache_key.length == key_length && !memcmp(table->s->table_cache_key.str, key, key_length)) return table; } return(0); } /* Reopen an table because the definition has changed. SYNOPSIS reopen_table() table Table object NOTES The data file for the table is already closed and the share is released The table has a 'dummy' share that mainly contains database and table name. RETURN 0 ok 1 error. The old table object is not changed. */ bool reopen_table(TABLE *table) { TABLE tmp; bool error= 1; Field **field; uint key,part; TABLE_LIST table_list; THD *thd= table->in_use; DBUG_ENTER("reopen_table"); DBUG_PRINT("tcache", ("table: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); DBUG_ASSERT(table->s->ref_count == 0); DBUG_ASSERT(!table->sort.io_cache); DBUG_ASSERT(!table->children_attached); #ifdef EXTRA_DEBUG if (table->db_stat) sql_print_error("Table %s had a open data handler in reopen_table", table->alias); #endif bzero((char*) &table_list, sizeof(TABLE_LIST)); table_list.db= table->s->db.str; table_list.table_name= table->s->table_name.str; table_list.table= table; if (wait_for_locked_table_names(thd, &table_list)) DBUG_RETURN(1); // Thread was killed if (open_unireg_entry(thd, &tmp, &table_list, table->alias, table->s->table_cache_key.str, table->s->table_cache_key.length, thd->mem_root, 0)) goto end; /* This list copies variables set by open_table */ tmp.tablenr= table->tablenr; tmp.used_fields= table->used_fields; tmp.const_table= table->const_table; tmp.null_row= table->null_row; tmp.maybe_null= table->maybe_null; tmp.status= table->status; tmp.s->table_map_id= table->s->table_map_id; /* Get state */ tmp.in_use= thd; tmp.reginfo.lock_type=table->reginfo.lock_type; tmp.grant= table->grant; /* Replace table in open list */ tmp.next= table->next; tmp.prev= table->prev; /* Preserve MERGE parent. */ tmp.parent= table->parent; /* Fix MERGE child list and check for unchanged union. */ if ((table->child_l || tmp.child_l) && fix_merge_after_open(table->child_l, table->child_last_l, tmp.child_l, tmp.child_last_l)) { VOID(closefrm(&tmp, 1)); // close file, free everything goto end; } delete table->triggers; if (table->file) VOID(closefrm(table, 1)); // close file, free everything *table= tmp; table->default_column_bitmaps(); table->file->change_table_ptr(table, table->s); DBUG_ASSERT(table->alias != 0); for (field=table->field ; *field ; field++) { (*field)->table= (*field)->orig_table= table; (*field)->table_name= &table->alias; } for (key=0 ; key < table->s->keys ; key++) { for (part=0 ; part < table->key_info[key].usable_key_parts ; part++) table->key_info[key].key_part[part].field->table= table; } if (table->triggers) table->triggers->set_table(table); /* Do not attach MERGE children here. The children might be reopened after the parent. Attach children after reopening all tables that require reopen. See for example reopen_tables(). */ broadcast_refresh(); error=0; end: DBUG_RETURN(error); } /** Close all instances of a table open by this thread and replace them with exclusive name-locks. @param thd Thread context @param db Database name for the table to be closed @param table_name Name of the table to be closed @note This function assumes that if we are not under LOCK TABLES, then there is only one table open and locked. This means that the function probably has to be adjusted before it can be used anywhere outside ALTER TABLE. @note Must not use TABLE_SHARE::table_name/db of the table being closed, the strings are used in a loop even after the share may be freed. */ void close_data_files_and_morph_locks(THD *thd, const char *db, const char *table_name) { TABLE *table; DBUG_ENTER("close_data_files_and_morph_locks"); safe_mutex_assert_owner(&LOCK_open); if (thd->lock) { /* If we are not under LOCK TABLES we should have only one table open and locked so it makes sense to remove the lock at once. */ mysql_unlock_tables(thd, thd->lock); thd->lock= 0; } /* Note that open table list may contain a name-lock placeholder for target table name if we process ALTER TABLE ... RENAME. So loop below makes sense even if we are not under LOCK TABLES. */ for (table=thd->open_tables; table ; table=table->next) { if (!strcmp(table->s->table_name.str, table_name) && !strcmp(table->s->db.str, db)) { if (thd->locked_tables) { if (table->parent) { /* If MERGE child, need to reopen parent too. This means that the first child to be closed will detach all children from the parent and close it. OTOH in most cases a MERGE table won't have multiple children with the same db.table_name. */ mysql_lock_remove(thd, thd->locked_tables, table->parent, TRUE); table->parent->open_placeholder= 1; close_handle_and_leave_table_as_lock(table->parent); } else mysql_lock_remove(thd, thd->locked_tables, table, TRUE); } table->open_placeholder= 1; close_handle_and_leave_table_as_lock(table); } } DBUG_VOID_RETURN; } /** Reattach MERGE children after reopen. @param[in] thd thread context @param[in,out] err_tables_p pointer to pointer of tables in error @return status @retval FALSE OK, err_tables_p unchanged @retval TRUE Error, err_tables_p contains table(s) */ static bool reattach_merge(THD *thd, TABLE **err_tables_p) { TABLE *table; TABLE *next; TABLE **prv_p= &thd->open_tables; bool error= FALSE; DBUG_ENTER("reattach_merge"); for (table= thd->open_tables; table; table= next) { next= table->next; DBUG_PRINT("tcache", ("check table: '%s'.'%s' 0x%lx next: 0x%lx", table->s->db.str, table->s->table_name.str, (long) table, (long) next)); /* Reattach children for MERGE tables with "closed data files" only. */ if (table->child_l && !table->children_attached) { DBUG_PRINT("tcache", ("MERGE parent, attach children")); if(table->file->extra(HA_EXTRA_ATTACH_CHILDREN)) { my_error(ER_CANT_REOPEN_TABLE, MYF(0), table->alias); error= TRUE; /* Remove table from open_tables. */ *prv_p= next; if (next) prv_p= &next->next; /* Stack table on error list. */ table->next= *err_tables_p; *err_tables_p= table; continue; } else { table->children_attached= TRUE; DBUG_PRINT("myrg", ("attached parent: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); } } prv_p= &table->next; } DBUG_RETURN(error); } /** Reopen all tables with closed data files. @param thd Thread context @param get_locks Should we get locks after reopening tables ? @param mark_share_as_old Mark share as old to protect from a impending global read lock. @note Since this function can't properly handle prelocking and create placeholders it should be used in very special situations like FLUSH TABLES or ALTER TABLE. In general case one should just repeat open_tables()/lock_tables() combination when one needs tables to be reopened (for example see open_and_lock_tables()). @note One should have lock on LOCK_open when calling this. @return FALSE in case of success, TRUE - otherwise. */ bool reopen_tables(THD *thd, bool get_locks, bool mark_share_as_old) { TABLE *table,*next,**prev; TABLE **tables,**tables_ptr; // For locks TABLE *err_tables= NULL; bool error=0, not_used; bool merge_table_found= FALSE; const uint flags= MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN | MYSQL_LOCK_IGNORE_GLOBAL_READ_LOCK | MYSQL_LOCK_IGNORE_FLUSH; DBUG_ENTER("reopen_tables"); if (!thd->open_tables) DBUG_RETURN(0); safe_mutex_assert_owner(&LOCK_open); if (get_locks) { /* The ptr is checked later Do not handle locks of MERGE children. */ uint opens=0; for (table= thd->open_tables; table ; table=table->next) if (!table->parent) opens++; DBUG_PRINT("tcache", ("open tables to lock: %u", opens)); tables= (TABLE**) my_alloca(sizeof(TABLE*)*opens); } else tables= &thd->open_tables; tables_ptr =tables; prev= &thd->open_tables; for (table=thd->open_tables; table ; table=next) { uint db_stat=table->db_stat; next=table->next; DBUG_PRINT("tcache", ("open table: '%s'.'%s' 0x%lx " "parent: 0x%lx db_stat: %u", table->s->db.str, table->s->table_name.str, (long) table, (long) table->parent, db_stat)); if (table->child_l && !db_stat) merge_table_found= TRUE; if (!tables || (!db_stat && reopen_table(table))) { my_error(ER_CANT_REOPEN_TABLE, MYF(0), table->alias); /* If we could not allocate 'tables', we may close open tables here. If a MERGE table is affected, detach the children first. It is not necessary to clear the child or parent table reference of this table because the TABLE is freed. But we need to clear the child or parent references of the other belonging tables so that they cannot be moved into the unused_tables chain with these pointers set. */ if (table->child_l || table->parent) detach_merge_children(table, TRUE); VOID(hash_delete(&open_cache,(uchar*) table)); error=1; } else { DBUG_PRINT("tcache", ("opened. need lock: %d", get_locks && !db_stat && !table->parent)); *prev= table; prev= &table->next; /* Do not handle locks of MERGE children. */ if (get_locks && !db_stat && !table->parent) *tables_ptr++= table; // need new lock on this if (mark_share_as_old) { table->s->version=0; table->open_placeholder= 0; } } } *prev=0; /* When all tables are open again, we can re-attach MERGE children to their parents. All TABLE objects are still present. */ DBUG_PRINT("tcache", ("re-attaching MERGE tables: %d", merge_table_found)); if (!error && merge_table_found && reattach_merge(thd, &err_tables)) { while (err_tables) { VOID(hash_delete(&open_cache, (uchar*) err_tables)); err_tables= err_tables->next; } } DBUG_PRINT("tcache", ("open tables to lock: %u", (uint) (tables_ptr - tables))); if (tables != tables_ptr) // Should we get back old locks { MYSQL_LOCK *lock; /* We should always get these locks. Anyway, we must not go into wait_for_tables() as it tries to acquire LOCK_open, which is already locked. */ thd->some_tables_deleted=0; if ((lock= mysql_lock_tables(thd, tables, (uint) (tables_ptr - tables), flags, ¬_used))) { thd->locked_tables=mysql_lock_merge(thd->locked_tables,lock); } else { /* This case should only happen if there is a bug in the reopen logic. Need to issue error message to have a reply for the application. Not exactly what happened though, but close enough. */ my_error(ER_LOCK_DEADLOCK, MYF(0)); error=1; } } if (get_locks && tables) { my_afree((uchar*) tables); } broadcast_refresh(); DBUG_RETURN(error); } /** Close handlers for tables in list, but leave the TABLE structure intact so that we can re-open these quickly. @param thd Thread context @param table Head of the list of TABLE objects @param morph_locks TRUE - remove locks which we have on tables being closed but ensure that no DML or DDL will sneak in before we will re-open the table (i.e. temporarily morph our table-level locks into name-locks). FALSE - otherwise @param send_refresh Should we awake waiters even if we didn't close any tables? */ static void close_old_data_files(THD *thd, TABLE *table, bool morph_locks, bool send_refresh) { bool found= send_refresh; DBUG_ENTER("close_old_data_files"); for (; table ; table=table->next) { DBUG_PRINT("tcache", ("checking table: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); DBUG_PRINT("tcache", ("needs refresh: %d is open: %u", table->needs_reopen_or_name_lock(), table->db_stat)); /* Reopen marked for flush. */ if (table->needs_reopen_or_name_lock()) { found=1; if (table->db_stat) { if (morph_locks) { /* Forward lock handling to MERGE parent. But unlock parent once only. */ TABLE *ulcktbl= table->parent ? table->parent : table; if (ulcktbl->lock_count) { /* Wake up threads waiting for table-level lock on this table so they won't sneak in when we will temporarily remove our lock on it. This will also give them a chance to close their instances of this table. */ mysql_lock_abort(thd, ulcktbl, TRUE); mysql_lock_remove(thd, thd->locked_tables, ulcktbl, TRUE); ulcktbl->lock_count= 0; } if ((ulcktbl != table) && ulcktbl->db_stat) { /* Close the parent too. Note that parent can come later in the list of tables. It will then be noticed as closed and as a placeholder. When this happens, do not clear the placeholder flag. See the branch below ("***"). */ ulcktbl->open_placeholder= 1; close_handle_and_leave_table_as_lock(ulcktbl); } /* We want to protect the table from concurrent DDL operations (like RENAME TABLE) until we will re-open and re-lock it. */ table->open_placeholder= 1; } close_handle_and_leave_table_as_lock(table); } else if (table->open_placeholder && !morph_locks) { /* We come here only in close-for-back-off scenario. So we have to "close" create placeholder here to avoid deadlocks (for example, in case of concurrent execution of CREATE TABLE t1 SELECT * FROM t2 and RENAME TABLE t2 TO t1). In close-for-re-open scenario we will probably want to let it stay. Note "***": We must not enter this branch if the placeholder flag has been set because of a former close through a child. See above the comment that refers to this note. */ table->open_placeholder= 0; } } } if (found) broadcast_refresh(); DBUG_VOID_RETURN; } /* Wait until all threads has closed the tables in the list We have also to wait if there is thread that has a lock on this table even if the table is closed */ bool table_is_used(TABLE *table, bool wait_for_name_lock) { DBUG_ENTER("table_is_used"); do { char *key= table->s->table_cache_key.str; uint key_length= table->s->table_cache_key.length; DBUG_PRINT("loop", ("table_name: %s", table->alias)); HASH_SEARCH_STATE state; for (TABLE *search= (TABLE*) hash_first(&open_cache, (uchar*) key, key_length, &state); search ; search= (TABLE*) hash_next(&open_cache, (uchar*) key, key_length, &state)) { DBUG_PRINT("info", ("share: 0x%lx " "open_placeholder: %d locked_by_name: %d " "db_stat: %u version: %lu", (ulong) search->s, search->open_placeholder, search->locked_by_name, search->db_stat, search->s->version)); if (search->in_use == table->in_use) continue; // Name locked by this thread /* We can't use the table under any of the following conditions: - There is an name lock on it (Table is to be deleted or altered) - If we are in flush table and we didn't execute the flush - If the table engine is open and it's an old version (We must wait until all engines are shut down to use the table) */ if ( (search->locked_by_name && wait_for_name_lock) || (search->is_name_opened() && search->needs_reopen_or_name_lock())) DBUG_RETURN(1); } } while ((table=table->next)); DBUG_RETURN(0); } /* Wait until all used tables are refreshed */ bool wait_for_tables(THD *thd) { bool result; DBUG_ENTER("wait_for_tables"); thd_proc_info(thd, "Waiting for tables"); pthread_mutex_lock(&LOCK_open); while (!thd->killed) { thd->some_tables_deleted=0; close_old_data_files(thd,thd->open_tables,0,dropping_tables != 0); mysql_ha_flush(thd); if (!table_is_used(thd->open_tables,1)) break; (void) pthread_cond_wait(&COND_refresh,&LOCK_open); } if (thd->killed) result= 1; // aborted else { /* Now we can open all tables without any interference */ thd_proc_info(thd, "Reopen tables"); thd->version= refresh_version; result=reopen_tables(thd,0,0); } pthread_mutex_unlock(&LOCK_open); thd_proc_info(thd, 0); DBUG_RETURN(result); } /* drop tables from locked list SYNOPSIS drop_locked_tables() thd Thread thandler db Database table_name Table name INFORMATION This is only called on drop tables The TABLE object for the dropped table is unlocked but still kept around as a name lock, which means that the table will be available for other thread as soon as we call unlock_table_names(). If there is multiple copies of the table locked, all copies except the first, which acts as a name lock, is removed. RETURN # If table existed, return table 0 Table was not locked */ TABLE *drop_locked_tables(THD *thd,const char *db, const char *table_name) { TABLE *table,*next,**prev, *found= 0; prev= &thd->open_tables; DBUG_ENTER("drop_locked_tables"); /* Note that we need to hold LOCK_open while changing the open_tables list. Another thread may work on it. (See: remove_table_from_cache(), mysql_wait_completed_table()) Closing a MERGE child before the parent would be fatal if the other thread tries to abort the MERGE lock in between. */ for (table= thd->open_tables; table ; table=next) { next=table->next; if (!strcmp(table->s->table_name.str, table_name) && !strcmp(table->s->db.str, db)) { /* If MERGE child, forward lock handling to parent. */ mysql_lock_remove(thd, thd->locked_tables, table->parent ? table->parent : table, TRUE); /* When closing a MERGE parent or child table, detach the children first. Clear child table references in case this object is opened again. */ if (table->child_l || table->parent) detach_merge_children(table, TRUE); if (!found) { found= table; /* Close engine table, but keep object around as a name lock */ if (table->db_stat) { table->db_stat= 0; table->file->close(); } } else { /* We already have a name lock, remove copy */ VOID(hash_delete(&open_cache,(uchar*) table)); } } else { *prev=table; prev= &table->next; } } *prev=0; if (found) broadcast_refresh(); if (thd->locked_tables && thd->locked_tables->table_count == 0) { my_free((uchar*) thd->locked_tables,MYF(0)); thd->locked_tables=0; } DBUG_RETURN(found); } /* If we have the table open, which only happens when a LOCK TABLE has been done on the table, change the lock type to a lock that will abort all other threads trying to get the lock. */ void abort_locked_tables(THD *thd,const char *db, const char *table_name) { TABLE *table; for (table= thd->open_tables; table ; table= table->next) { if (!strcmp(table->s->table_name.str, table_name) && !strcmp(table->s->db.str, db)) { /* If MERGE child, forward lock handling to parent. */ mysql_lock_abort(thd, table->parent ? table->parent : table, TRUE); break; } } } /* Function to assign a new table map id to a table share. PARAMETERS share - Pointer to table share structure DESCRIPTION We are intentionally not checking that share->mutex is locked since this function should only be called when opening a table share and before it is entered into the table_def_cache (meaning that it cannot be fetched by another thread, even accidentally). PRE-CONDITION(S) share is non-NULL The LOCK_open mutex is locked POST-CONDITION(S) share->table_map_id is given a value that with a high certainty is not used by any other table (the only case where a table id can be reused is on wrap-around, which means more than 4 billion table share opens have been executed while one table was open all the time). share->table_map_id is not ~0UL. */ void assign_new_table_id(TABLE_SHARE *share) { static ulong last_table_id= ~0UL; DBUG_ENTER("assign_new_table_id"); /* Preconditions */ DBUG_ASSERT(share != NULL); safe_mutex_assert_owner(&LOCK_open); ulong tid= ++last_table_id; /* get next id */ /* There is one reserved number that cannot be used. Remember to change this when 6-byte global table id's are introduced. */ if (unlikely(tid == ~0UL)) tid= ++last_table_id; share->table_map_id= tid; DBUG_PRINT("info", ("table_id=%lu", tid)); /* Post conditions */ DBUG_ASSERT(share->table_map_id != ~0UL); DBUG_VOID_RETURN; } /* Load a table definition from file and open unireg table SYNOPSIS open_unireg_entry() thd Thread handle entry Store open table definition here table_list TABLE_LIST with db, table_name & belong_to_view alias Alias name cache_key Key for share_cache cache_key_length length of cache_key mem_root temporary mem_root for parsing flags the OPEN_VIEW_NO_PARSE flag to be passed to openfrm()/open_new_frm() NOTES Extra argument for open is taken from thd->open_options One must have a lock on LOCK_open when calling this function RETURN 0 ok # Error */ static int open_unireg_entry(THD *thd, TABLE *entry, TABLE_LIST *table_list, const char *alias, char *cache_key, uint cache_key_length, MEM_ROOT *mem_root, uint flags) { int error; TABLE_SHARE *share; uint discover_retry_count= 0; DBUG_ENTER("open_unireg_entry"); safe_mutex_assert_owner(&LOCK_open); retry: if (!(share= get_table_share_with_create(thd, table_list, cache_key, cache_key_length, OPEN_VIEW | table_list->i_s_requested_object, &error))) DBUG_RETURN(1); if (share->is_view) { if (table_list->i_s_requested_object & OPEN_TABLE_ONLY) goto err; /* Open view */ error= (int) open_new_frm(thd, share, alias, (uint) (HA_OPEN_KEYFILE | HA_OPEN_RNDFILE | HA_GET_INDEX | HA_TRY_READ_ONLY), READ_KEYINFO | COMPUTE_TYPES | EXTRA_RECORD | (flags & OPEN_VIEW_NO_PARSE), thd->open_options, entry, table_list, mem_root); if (error) goto err; /* TODO: Don't free this */ release_table_share(share, RELEASE_NORMAL); DBUG_RETURN((flags & OPEN_VIEW_NO_PARSE)? -1 : 0); } if (table_list->i_s_requested_object & OPEN_VIEW_ONLY) goto err; while ((error= open_table_from_share(thd, share, alias, (uint) (HA_OPEN_KEYFILE | HA_OPEN_RNDFILE | HA_GET_INDEX | HA_TRY_READ_ONLY), (READ_KEYINFO | COMPUTE_TYPES | EXTRA_RECORD), thd->open_options, entry, FALSE))) { if (error == 7) // Table def changed { share->version= 0; // Mark share as old if (discover_retry_count++) // Retry once goto err; /* TODO: Here we should wait until all threads has released the table. For now we do one retry. This may cause a deadlock if there is other threads waiting for other tables used by this thread. Proper fix would be to if the second retry failed: - Mark that table def changed - Return from open table - Close all tables used by this thread - Start waiting that the share is released - Retry by opening all tables again */ if (ha_create_table_from_engine(thd, table_list->db, table_list->table_name)) goto err; /* TO BE FIXED To avoid deadlock, only wait for release if no one else is using the share. */ if (share->ref_count != 1) goto err; /* Free share and wait until it's released by all threads */ release_table_share(share, RELEASE_WAIT_FOR_DROP); if (!thd->killed) { mysql_reset_errors(thd, 1); // Clear warnings thd->clear_error(); // Clear error message goto retry; } DBUG_RETURN(1); } if (!entry->s || !entry->s->crashed) goto err; // Code below is for repairing a crashed file if ((error= lock_table_name(thd, table_list, TRUE))) { if (error < 0) goto err; if (wait_for_locked_table_names(thd, table_list)) { unlock_table_name(thd, table_list); goto err; } } pthread_mutex_unlock(&LOCK_open); thd->clear_error(); // Clear error message error= 0; if (open_table_from_share(thd, share, alias, (uint) (HA_OPEN_KEYFILE | HA_OPEN_RNDFILE | HA_GET_INDEX | HA_TRY_READ_ONLY), READ_KEYINFO | COMPUTE_TYPES | EXTRA_RECORD, ha_open_options | HA_OPEN_FOR_REPAIR, entry, FALSE) || ! entry->file || (entry->file->is_crashed() && entry->file->ha_check_and_repair(thd))) { /* Give right error message */ thd->clear_error(); my_error(ER_NOT_KEYFILE, MYF(0), share->table_name.str, my_errno); sql_print_error("Couldn't repair table: %s.%s", share->db.str, share->table_name.str); if (entry->file) closefrm(entry, 0); error=1; } else thd->clear_error(); // Clear error message pthread_mutex_lock(&LOCK_open); unlock_table_name(thd, table_list); if (error) goto err; break; } if (Table_triggers_list::check_n_load(thd, share->db.str, share->table_name.str, entry, 0)) { closefrm(entry, 0); goto err; } /* If we are here, there was no fatal error (but error may be still unitialized). */ if (unlikely(entry->file->implicit_emptied)) { entry->file->implicit_emptied= 0; if (mysql_bin_log.is_open()) { char *query, *end; uint query_buf_size= 20 + share->db.length + share->table_name.length +1; if ((query= (char*) my_malloc(query_buf_size,MYF(MY_WME)))) { /* this DELETE FROM is needed even with row-based binlogging */ end = strxmov(strmov(query, "DELETE FROM `"), share->db.str,"`.`",share->table_name.str,"`", NullS); thd->binlog_query(THD::STMT_QUERY_TYPE, query, (ulong)(end-query), FALSE, FALSE); my_free(query, MYF(0)); } else { /* As replication is maybe going to be corrupted, we need to warn the DBA on top of warning the client (which will automatically be done because of MYF(MY_WME) in my_malloc() above). */ sql_print_error("When opening HEAP table, could not allocate memory " "to write 'DELETE FROM `%s`.`%s`' to the binary log", table_list->db, table_list->table_name); delete entry->triggers; closefrm(entry, 0); goto err; } } } DBUG_RETURN(0); err: release_table_share(share, RELEASE_NORMAL); DBUG_RETURN(1); } /** @brief Add list of MERGE children to a TABLE_LIST list. @param[in] tlist the parent TABLE_LIST object just opened @return status @retval 0 OK @retval != 0 Error @detail When a MERGE parent table has just been opened, insert the TABLE_LIST chain from the MERGE handle into the table list used for opening tables for this statement. This lets the children be opened too. */ static int add_merge_table_list(TABLE_LIST *tlist) { TABLE *parent= tlist->table; TABLE_LIST *child_l; DBUG_ENTER("add_merge_table_list"); DBUG_PRINT("myrg", ("table: '%s'.'%s' 0x%lx", parent->s->db.str, parent->s->table_name.str, (long) parent)); /* Must not call this with attached children. */ DBUG_ASSERT(!parent->children_attached); /* Must not call this with children list in place. */ DBUG_ASSERT(tlist->next_global != parent->child_l); /* Prevent inclusion of another MERGE table. Could make infinite recursion. */ if (tlist->parent_l) { my_error(ER_ADMIN_WRONG_MRG_TABLE, MYF(0), tlist->alias); DBUG_RETURN(1); } /* Fix children.*/ for (child_l= parent->child_l; ; child_l= child_l->next_global) { /* Note: child_l->table may still be set if this parent was taken from the unused_tables chain. Ignore this fact here. The reference will be replaced by the handler in ::extra(HA_EXTRA_ATTACH_CHILDREN). */ /* Set lock type. */ child_l->lock_type= tlist->lock_type; /* Set parent reference. */ child_l->parent_l= tlist; /* Break when this was the last child. */ if (&child_l->next_global == parent->child_last_l) break; } /* Insert children into the table list. */ *parent->child_last_l= tlist->next_global; tlist->next_global= parent->child_l; /* Do not fix the prev_global pointers. We will remove the chain soon anyway. */ DBUG_RETURN(0); } /** @brief Attach MERGE children to the parent. @param[in] tlist the child TABLE_LIST object just opened @return status @retval 0 OK @retval != 0 Error @note This is called when the last MERGE child has just been opened, let the handler attach the MyISAM tables to the MERGE table. Remove MERGE TABLE_LIST chain from the statement list so that it cannot be changed or freed. */ static int attach_merge_children(TABLE_LIST *tlist) { TABLE *parent= tlist->parent_l->table; int error; DBUG_ENTER("attach_merge_children"); DBUG_PRINT("myrg", ("table: '%s'.'%s' 0x%lx", parent->s->db.str, parent->s->table_name.str, (long) parent)); /* Must not call this with attached children. */ DBUG_ASSERT(!parent->children_attached); /* Must call this with children list in place. */ DBUG_ASSERT(tlist->parent_l->next_global == parent->child_l); /* Attach MyISAM tables to MERGE table. */ error= parent->file->extra(HA_EXTRA_ATTACH_CHILDREN); /* Remove children from the table list. Even in case of an error. This should prevent tampering with them. */ tlist->parent_l->next_global= *parent->child_last_l; /* Do not fix the last childs next_global pointer. It is needed for stepping to the next table in the enclosing loop in open_tables(). Do not fix prev_global pointers. We did not set them. */ if (error) { DBUG_PRINT("error", ("attaching MERGE children failed: %d", my_errno)); parent->file->print_error(error, MYF(0)); DBUG_RETURN(1); } parent->children_attached= TRUE; DBUG_PRINT("myrg", ("attached parent: '%s'.'%s' 0x%lx", parent->s->db.str, parent->s->table_name.str, (long) parent)); /* Note that we have the cildren in the thd->open_tables list at this point. */ DBUG_RETURN(0); } /** @brief Detach MERGE children from the parent. @note Call this before the first table of a MERGE table (parent or child) is closed. When closing thread tables at end of statement, both parent and children are in thd->open_tables and will be closed. In most cases the children will be closed before the parent. They are opened after the parent and thus stacked into thd->open_tables before it. To avoid that we touch a closed children in any way, we must detach the children from the parent when the first belonging table is closed (parent or child). All references to the children should be removed on handler level and optionally on table level. @note Assure that you call it for a MERGE parent or child only. Either table->child_l or table->parent must be set. @param[in] table the TABLE object of the parent @param[in] clear_refs if to clear TABLE references this must be true when called from close_thread_tables() to enable fresh open in open_tables() it must be false when called in preparation for reopen_tables() */ void detach_merge_children(TABLE *table, bool clear_refs) { TABLE_LIST *child_l; TABLE *parent= table->child_l ? table : table->parent; bool first_detach; DBUG_ENTER("detach_merge_children"); /* Either table->child_l or table->parent must be set. Parent must have child_l set. */ DBUG_ASSERT(parent && parent->child_l); DBUG_PRINT("myrg", ("table: '%s'.'%s' 0x%lx clear_refs: %d", table->s->db.str, table->s->table_name.str, (long) table, clear_refs)); DBUG_PRINT("myrg", ("parent: '%s'.'%s' 0x%lx", parent->s->db.str, parent->s->table_name.str, (long) parent)); /* In a open_tables() loop it can happen that not all tables have their children attached yet. Also this is called for every child and the parent from close_thread_tables(). */ if ((first_detach= parent->children_attached)) { VOID(parent->file->extra(HA_EXTRA_DETACH_CHILDREN)); parent->children_attached= FALSE; DBUG_PRINT("myrg", ("detached parent: '%s'.'%s' 0x%lx", parent->s->db.str, parent->s->table_name.str, (long) parent)); } else DBUG_PRINT("myrg", ("parent is already detached")); if (clear_refs) { /* In any case clear the own parent reference. (***) */ table->parent= NULL; /* On the first detach, clear all references. If this table is the parent, we still may need to clear the child references. The first detach might not have done this. */ if (first_detach || (table == parent)) { /* Clear TABLE references to force new assignment at next open. */ for (child_l= parent->child_l; ; child_l= child_l->next_global) { /* Do not DBUG_ASSERT(child_l->table); open_tables might be incomplete. Clear the parent reference of the children only on the first detach. The children might already be closed. They will clear it themseves when this function is called for them with 'clear_refs' true. See above "(***)". */ if (first_detach && child_l->table) child_l->table->parent= NULL; /* Clear the table reference to force new assignment at next open. */ child_l->table= NULL; /* Break when this was the last child. */ if (&child_l->next_global == parent->child_last_l) break; } } } DBUG_VOID_RETURN; } /** @brief Fix MERGE children after open. @param[in] old_child_list first list member from original table @param[in] old_last pointer to &next_global of last list member @param[in] new_child_list first list member from freshly opened table @param[in] new_last pointer to &next_global of last list member @return mismatch @retval FALSE OK, no mismatch @retval TRUE Error, lists mismatch @detail Main action is to copy TABLE reference for each member of original child list to new child list. After a fresh open these references are NULL. Assign the old children to the new table. Some of them might also be reopened or will be reopened soon. Other action is to verify that the table definition with respect to the UNION list did not change. @note This function terminates the child list if the respective '*_last' pointer is non-NULL. Do not call it from a place where the list is embedded in another list and this would break it. Terminating the list is required for example in the first reopen_table() after open_tables(). open_tables() requires the end of the list not to be terminated because other tables could follow behind the child list. If a '*_last' pointer is NULL, the respective list is assumed to be NULL terminated. */ bool fix_merge_after_open(TABLE_LIST *old_child_list, TABLE_LIST **old_last, TABLE_LIST *new_child_list, TABLE_LIST **new_last) { bool mismatch= FALSE; DBUG_ENTER("fix_merge_after_open"); DBUG_PRINT("myrg", ("old last addr: 0x%lx new last addr: 0x%lx", (long) old_last, (long) new_last)); /* Terminate the lists for easier check of list end. */ if (old_last) *old_last= NULL; if (new_last) *new_last= NULL; for (;;) { DBUG_PRINT("myrg", ("old list item: 0x%lx new list item: 0x%lx", (long) old_child_list, (long) new_child_list)); /* Break if one of the list is at its end. */ if (!old_child_list || !new_child_list) break; /* Old table has references to child TABLEs. */ DBUG_ASSERT(old_child_list->table); /* New table does not yet have references to child TABLEs. */ DBUG_ASSERT(!new_child_list->table); DBUG_PRINT("myrg", ("old table: '%s'.'%s' new table: '%s'.'%s'", old_child_list->db, old_child_list->table_name, new_child_list->db, new_child_list->table_name)); /* Child db.table names must match. */ if (strcmp(old_child_list->table_name, new_child_list->table_name) || strcmp(old_child_list->db, new_child_list->db)) break; /* Copy TABLE reference. Child TABLE objects are still in place though not necessarily open yet. */ DBUG_PRINT("myrg", ("old table ref: 0x%lx replaces new table ref: 0x%lx", (long) old_child_list->table, (long) new_child_list->table)); new_child_list->table= old_child_list->table; /* Step both lists. */ old_child_list= old_child_list->next_global; new_child_list= new_child_list->next_global; } DBUG_PRINT("myrg", ("end of list, mismatch: %d", mismatch)); /* If the list pointers are not both NULL after the loop, then the lists differ. If the are both identical, but not NULL, then they have at least one table in common and hence the rest of the list would be identical too. But in this case the loop woul run until the list end, where both pointers would become NULL. */ if (old_child_list != new_child_list) mismatch= TRUE; if (mismatch) my_error(ER_TABLE_DEF_CHANGED, MYF(0)); DBUG_RETURN(mismatch); } /* Open all tables in list SYNOPSIS open_tables() thd - thread handler start - list of tables in/out counter - number of opened tables will be return using this parameter flags - bitmap of flags to modify how the tables will be open: MYSQL_LOCK_IGNORE_FLUSH - open table even if someone has done a flush or namelock on it. NOTE Unless we are already in prelocked mode, this function will also precache all SP/SFs explicitly or implicitly (via views and triggers) used by the query and add tables needed for their execution to table list. If resulting tables list will be non empty it will mark query as requiring precaching. Prelocked mode will be enabled for such query during lock_tables() call. If query for which we are opening tables is already marked as requiring prelocking it won't do such precaching and will simply reuse table list which is already built. RETURN 0 - OK -1 - error */ int open_tables(THD *thd, TABLE_LIST **start, uint *counter, uint flags) { TABLE_LIST *tables= NULL; bool refresh; int result=0; MEM_ROOT new_frm_mem; /* Also used for indicating that prelocking is need */ TABLE_LIST **query_tables_last_own; bool safe_to_ignore_table; DBUG_ENTER("open_tables"); /* temporary mem_root for new .frm parsing. TODO: variables for size */ init_sql_alloc(&new_frm_mem, 8024, 8024); thd->current_tablenr= 0; restart: *counter= 0; query_tables_last_own= 0; thd_proc_info(thd, "Opening tables"); /* If we are not already executing prelocked statement and don't have statement for which table list for prelocking is already built, let us cache routines and try to build such table list. */ if (!thd->prelocked_mode && !thd->lex->requires_prelocking() && thd->lex->uses_stored_routines()) { bool first_no_prelocking, need_prelocking; TABLE_LIST **save_query_tables_last= thd->lex->query_tables_last; DBUG_ASSERT(thd->lex->query_tables == *start); sp_get_prelocking_info(thd, &need_prelocking, &first_no_prelocking); if (sp_cache_routines_and_add_tables(thd, thd->lex, first_no_prelocking)) { /* Serious error during reading stored routines from mysql.proc table. Something's wrong with the table or its contents, and an error has been emitted; we must abort. */ result= -1; goto err; } else if (need_prelocking) { query_tables_last_own= save_query_tables_last; *start= thd->lex->query_tables; } } /* For every table in the list of tables to open, try to find or open a table. */ for (tables= *start; tables ;tables= tables->next_global) { DBUG_PRINT("tcache", ("opening table: '%s'.'%s' item: 0x%lx", tables->db, tables->table_name, (long) tables)); safe_to_ignore_table= FALSE; /* Ignore placeholders for derived tables. After derived tables processing, link to created temporary table will be put here. If this is derived table for view then we still want to process routines used by this view. */ if (tables->derived) { if (tables->view) goto process_view_routines; continue; } /* If this TABLE_LIST object is a placeholder for an information_schema table, create a temporary table to represent the information_schema table in the query. Do not fill it yet - will be filled during execution. */ if (tables->schema_table) { if (!mysql_schema_table(thd, thd->lex, tables)) continue; DBUG_RETURN(-1); } (*counter)++; /* Not a placeholder: must be a base table or a view, and the table is not opened yet. Try to open the table. */ if (!tables->table) { if (tables->prelocking_placeholder) { /* For the tables added by the pre-locking code, attempt to open the table but fail silently if the table does not exist. The real failure will occur when/if a statement attempts to use that table. */ Prelock_error_handler prelock_handler; thd->push_internal_handler(& prelock_handler); tables->table= open_table(thd, tables, &new_frm_mem, &refresh, flags); thd->pop_internal_handler(); safe_to_ignore_table= prelock_handler.safely_trapped_errors(); } else tables->table= open_table(thd, tables, &new_frm_mem, &refresh, flags); } else DBUG_PRINT("tcache", ("referenced table: '%s'.'%s' 0x%lx", tables->db, tables->table_name, (long) tables->table)); if (!tables->table) { free_root(&new_frm_mem, MYF(MY_KEEP_PREALLOC)); if (tables->view) { /* VIEW placeholder */ (*counter)--; /* tables->next_global list consists of two parts: 1) Query tables and underlying tables of views. 2) Tables used by all stored routines that this statement invokes on execution. We need to know where the bound between these two parts is. If we've just opened a view, which was the last table in part #1, and it has added its base tables after itself, adjust the boundary pointer accordingly. */ if (query_tables_last_own == &(tables->next_global) && tables->view->query_tables) query_tables_last_own= tables->view->query_tables_last; /* Let us free memory used by 'sroutines' hash here since we never call destructor for this LEX. */ hash_free(&tables->view->sroutines); goto process_view_routines; } /* If in a MERGE table open, we need to remove the children list from statement table list before restarting. Otherwise the list will be inserted another time. */ if (tables->parent_l) { TABLE_LIST *parent_l= tables->parent_l; /* The parent table should be correctly open at this point. */ DBUG_ASSERT(parent_l->table); parent_l->next_global= *parent_l->table->child_last_l; } if (refresh) // Refresh in progress { /* We have met name-locked or old version of table. Now we have to close all tables which are not up to date. We also have to throw away set of prelocked tables (and thus close tables from this set that were open by now) since it possible that one of tables which determined its content was changed. Instead of implementing complex/non-robust logic mentioned above we simply close and then reopen all tables. In order to prepare for recalculation of set of prelocked tables we pretend that we have finished calculation which we were doing currently. */ if (query_tables_last_own) thd->lex->mark_as_requiring_prelocking(query_tables_last_own); close_tables_for_reopen(thd, start); goto restart; } if (safe_to_ignore_table) { DBUG_PRINT("info", ("open_table: ignoring table '%s'.'%s'", tables->db, tables->alias)); continue; } result= -1; // Fatal error break; } else { /* If we are not already in prelocked mode and extended table list is not yet built and we have trigger for table being opened then we should cache all routines used by its triggers and add their tables to prelocking list. If we lock table for reading we won't update it so there is no need to process its triggers since they never will be activated. */ if (!thd->prelocked_mode && !thd->lex->requires_prelocking() && tables->table->triggers && tables->lock_type >= TL_WRITE_ALLOW_WRITE) { if (!query_tables_last_own) query_tables_last_own= thd->lex->query_tables_last; if (sp_cache_routines_and_add_tables_for_triggers(thd, thd->lex, tables)) { /* Serious error during reading stored routines from mysql.proc table. Something's wrong with the table or its contents, and an error has been emitted; we must abort. */ result= -1; goto err; } } free_root(&new_frm_mem, MYF(MY_KEEP_PREALLOC)); } if (tables->lock_type != TL_UNLOCK && ! thd->locked_tables) tables->table->reginfo.lock_type= tables->lock_type == TL_WRITE_DEFAULT ? thd->update_lock_default : tables->lock_type; tables->table->grant= tables->grant; /* Attach MERGE children if not locked already. */ DBUG_PRINT("tcache", ("is parent: %d is child: %d", test(tables->table->child_l), test(tables->parent_l))); DBUG_PRINT("tcache", ("in lock tables: %d in prelock mode: %d", test(thd->locked_tables), test(thd->prelocked_mode))); if (((!thd->locked_tables && !thd->prelocked_mode) || tables->table->s->tmp_table) && ((tables->table->child_l && add_merge_table_list(tables)) || (tables->parent_l && (&tables->next_global == tables->parent_l->table->child_last_l) && attach_merge_children(tables)))) { result= -1; goto err; } process_view_routines: /* Again we may need cache all routines used by this view and add tables used by them to table list. */ if (tables->view && !thd->prelocked_mode && !thd->lex->requires_prelocking() && tables->view->uses_stored_routines()) { /* We have at least one table in TL here. */ if (!query_tables_last_own) query_tables_last_own= thd->lex->query_tables_last; if (sp_cache_routines_and_add_tables_for_view(thd, thd->lex, tables)) { /* Serious error during reading stored routines from mysql.proc table. Something is wrong with the table or its contents, and an error has been emitted; we must abort. */ result= -1; goto err; } } } err: thd_proc_info(thd, 0); free_root(&new_frm_mem, MYF(0)); // Free pre-alloced block if (query_tables_last_own) thd->lex->mark_as_requiring_prelocking(query_tables_last_own); if (result && tables) { /* Some functions determine success as (tables->table != NULL). tables->table is in thd->open_tables. It won't go lost. If the error happens on a MERGE child, clear the parents TABLE reference. */ if (tables->parent_l) tables->parent_l->table= NULL; tables->table= NULL; } DBUG_PRINT("tcache", ("returning: %d", result)); DBUG_RETURN(result); } /* Check that lock is ok for tables; Call start stmt if ok SYNOPSIS check_lock_and_start_stmt() thd Thread handle table_list Table to check lock_type Lock used for table RETURN VALUES 0 ok 1 error */ static bool check_lock_and_start_stmt(THD *thd, TABLE *table, thr_lock_type lock_type) { int error; DBUG_ENTER("check_lock_and_start_stmt"); if ((int) lock_type >= (int) TL_WRITE_ALLOW_READ && (int) table->reginfo.lock_type < (int) TL_WRITE_ALLOW_READ) { my_error(ER_TABLE_NOT_LOCKED_FOR_WRITE, MYF(0),table->alias); DBUG_RETURN(1); } if ((error=table->file->start_stmt(thd, lock_type))) { table->file->print_error(error,MYF(0)); DBUG_RETURN(1); } DBUG_RETURN(0); } /** @brief Open and lock one table @param[in] thd thread handle @param[in] table_l table to open is first table in this list @param[in] lock_type lock to use for table @return table @retval != NULL OK, opened table returned @retval NULL Error @note If ok, the following are also set: table_list->lock_type lock_type table_list->table table @note If table_l is a list, not a single table, the list is temporarily broken. @detail This function is meant as a replacement for open_ltable() when MERGE tables can be opened. open_ltable() cannot open MERGE tables. There may be more differences between open_n_lock_single_table() and open_ltable(). One known difference is that open_ltable() does neither call decide_logging_format() nor handle some other logging and locking issues because it does not call lock_tables(). */ TABLE *open_n_lock_single_table(THD *thd, TABLE_LIST *table_l, thr_lock_type lock_type) { TABLE_LIST *save_next_global; DBUG_ENTER("open_n_lock_single_table"); /* Remember old 'next' pointer. */ save_next_global= table_l->next_global; /* Break list. */ table_l->next_global= NULL; /* Set requested lock type. */ table_l->lock_type= lock_type; /* Allow to open real tables only. */ table_l->required_type= FRMTYPE_TABLE; /* Open the table. */ if (simple_open_n_lock_tables(thd, table_l)) table_l->table= NULL; /* Just to be sure. */ /* Restore list. */ table_l->next_global= save_next_global; DBUG_RETURN(table_l->table); } /* Open and lock one table SYNOPSIS open_ltable() thd Thread handler table_list Table to open is first table in this list lock_type Lock to use for open lock_flags Flags passed to mysql_lock_table NOTE This function don't do anything like SP/SF/views/triggers analysis done in open_tables(). It is intended for opening of only one concrete table. And used only in special contexts. RETURN VALUES table Opened table 0 Error If ok, the following are also set: table_list->lock_type lock_type table_list->table table */ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type lock_type, uint lock_flags) { TABLE *table; bool refresh; DBUG_ENTER("open_ltable"); thd_proc_info(thd, "Opening table"); thd->current_tablenr= 0; /* open_ltable can be used only for BASIC TABLEs */ table_list->required_type= FRMTYPE_TABLE; while (!(table= open_table(thd, table_list, thd->mem_root, &refresh, 0)) && refresh) ; if (table) { if (table->child_l) { /* A MERGE table must not come here. */ /* purecov: begin tested */ my_error(ER_WRONG_OBJECT, MYF(0), table->s->db.str, table->s->table_name.str, "BASE TABLE"); table= 0; goto end; /* purecov: end */ } table_list->lock_type= lock_type; table_list->table= table; table->grant= table_list->grant; if (thd->locked_tables) { if (check_lock_and_start_stmt(thd, table, lock_type)) table= 0; } else { DBUG_ASSERT(thd->lock == 0); // You must lock everything at once if ((table->reginfo.lock_type= lock_type) != TL_UNLOCK) if (! (thd->lock= mysql_lock_tables(thd, &table_list->table, 1, lock_flags, &refresh))) table= 0; } } end: thd_proc_info(thd, 0); DBUG_RETURN(table); } /* Open all tables in list, locks them and optionally process derived tables. SYNOPSIS open_and_lock_tables_derived() thd - thread handler tables - list of tables for open&locking derived - if to handle derived tables RETURN FALSE - ok TRUE - error NOTE The lock will automaticaly be freed by close_thread_tables() NOTE There are two convenience functions: - simple_open_n_lock_tables(thd, tables) without derived handling - open_and_lock_tables(thd, tables) with derived handling Both inline functions call open_and_lock_tables_derived() with the third argument set appropriately. */ bool open_and_lock_tables_derived(THD *thd, TABLE_LIST *tables, bool derived) { uint counter; bool need_reopen; DBUG_ENTER("open_and_lock_tables_derived"); DBUG_PRINT("enter", ("derived handling: %d", derived)); for ( ; ; ) { if (open_tables(thd, &tables, &counter, 0)) DBUG_RETURN(-1); DBUG_EXECUTE_IF("sleep_open_and_lock_after_open", { const char *old_proc_info= thd->proc_info; thd->proc_info= "DBUG sleep"; my_sleep(6000000); thd->proc_info= old_proc_info;}); if (!lock_tables(thd, tables, counter, &need_reopen)) break; if (!need_reopen) DBUG_RETURN(-1); close_tables_for_reopen(thd, &tables); } if (derived && (mysql_handle_derived(thd->lex, &mysql_derived_prepare) || (thd->fill_derived_tables() && mysql_handle_derived(thd->lex, &mysql_derived_filling)))) DBUG_RETURN(TRUE); /* purecov: inspected */ DBUG_RETURN(0); } /* Open all tables in list and process derived tables SYNOPSIS open_normal_and_derived_tables thd - thread handler tables - list of tables for open flags - bitmap of flags to modify how the tables will be open: MYSQL_LOCK_IGNORE_FLUSH - open table even if someone has done a flush or namelock on it. RETURN FALSE - ok TRUE - error NOTE This is to be used on prepare stage when you don't read any data from the tables. */ bool open_normal_and_derived_tables(THD *thd, TABLE_LIST *tables, uint flags) { uint counter; DBUG_ENTER("open_normal_and_derived_tables"); DBUG_ASSERT(!thd->fill_derived_tables()); if (open_tables(thd, &tables, &counter, flags) || mysql_handle_derived(thd->lex, &mysql_derived_prepare)) DBUG_RETURN(TRUE); /* purecov: inspected */ DBUG_RETURN(0); } /* Mark all real tables in the list as free for reuse. SYNOPSIS mark_real_tables_as_free_for_reuse() thd - thread context table - head of the list of tables DESCRIPTION Marks all real tables in the list (i.e. not views, derived or schema tables) as free for reuse. */ static void mark_real_tables_as_free_for_reuse(TABLE_LIST *table) { for (; table; table= table->next_global) if (!table->placeholder()) table->table->query_id= 0; } /** Decide on logging format to use for the statement. Compute the capabilities vector for the involved storage engines and mask out the flags for the binary log. Right now, the binlog flags only include the capabilities of the storage engines, so this is safe. We now have three alternatives that prevent the statement from being loggable: 1. If there are no capabilities left (all flags are clear) it is not possible to log the statement at all, so we roll back the statement and report an error. 2. Statement mode is set, but the capabilities indicate that statement format is not possible. 3. Row mode is set, but the capabilities indicate that row format is not possible. 4. Statement is unsafe, but the capabilities indicate that row format is not possible. If we are in MIXED mode, we then decide what logging format to use: 1. If the statement is unsafe, row-based logging is used. 2. If statement-based logging is not possible, row-based logging is used. 3. Otherwise, statement-based logging is used. @param thd Client thread @param tables Tables involved in the query */ int decide_logging_format(THD *thd, TABLE_LIST *tables) { if (mysql_bin_log.is_open() && (thd->options & OPTION_BIN_LOG)) { handler::Table_flags flags_some_set= handler::Table_flags(); handler::Table_flags flags_all_set= ~handler::Table_flags(); my_bool multi_engine= FALSE; void* prev_ht= NULL; for (TABLE_LIST *table= tables; table; table= table->next_global) { if (!table->placeholder() && table->lock_type >= TL_WRITE_ALLOW_WRITE) { ulonglong const flags= table->table->file->ha_table_flags(); DBUG_PRINT("info", ("table: %s; ha_table_flags: %s%s", table->table_name, FLAGSTR(flags, HA_BINLOG_STMT_CAPABLE), FLAGSTR(flags, HA_BINLOG_ROW_CAPABLE))); if (prev_ht && prev_ht != table->table->file->ht) multi_engine= TRUE; prev_ht= table->table->file->ht; flags_all_set &= flags; flags_some_set |= flags; } } DBUG_PRINT("info", ("flags_all_set: %s%s", FLAGSTR(flags_all_set, HA_BINLOG_STMT_CAPABLE), FLAGSTR(flags_all_set, HA_BINLOG_ROW_CAPABLE))); DBUG_PRINT("info", ("flags_some_set: %s%s", FLAGSTR(flags_some_set, HA_BINLOG_STMT_CAPABLE), FLAGSTR(flags_some_set, HA_BINLOG_ROW_CAPABLE))); DBUG_PRINT("info", ("thd->variables.binlog_format: %ld", thd->variables.binlog_format)); DBUG_PRINT("info", ("multi_engine: %s", multi_engine ? "TRUE" : "FALSE")); int error= 0; if (flags_all_set == 0) { my_error((error= ER_BINLOG_LOGGING_IMPOSSIBLE), MYF(0), "Statement cannot be logged to the binary log in" " row-based nor statement-based format"); } else if (thd->variables.binlog_format == BINLOG_FORMAT_STMT && (flags_all_set & HA_BINLOG_STMT_CAPABLE) == 0) { my_error((error= ER_BINLOG_LOGGING_IMPOSSIBLE), MYF(0), "Statement-based format required for this statement," " but not allowed by this combination of engines"); } else if ((thd->variables.binlog_format == BINLOG_FORMAT_ROW || thd->lex->is_stmt_unsafe()) && (flags_all_set & HA_BINLOG_ROW_CAPABLE) == 0) { my_error((error= ER_BINLOG_LOGGING_IMPOSSIBLE), MYF(0), "Row-based format required for this statement," " but not allowed by this combination of engines"); } /* If more than one engine is involved in the statement and at least one is doing it's own logging (is *self-logging*), the statement cannot be logged atomically, so we generate an error rather than allowing the binlog to become corrupt. */ if (multi_engine && (flags_some_set & HA_HAS_OWN_BINLOGGING)) { error= ER_BINLOG_LOGGING_IMPOSSIBLE; my_error(error, MYF(0), "Statement cannot be written atomically since more" " than one engine involved and at least one engine" " is self-logging"); } DBUG_PRINT("info", ("error: %d", error)); if (error) { ha_rollback_stmt(thd); return -1; } /* We switch to row-based format if we are in mixed mode and one of the following are true: 1. If the statement is unsafe 2. If statement format cannot be used Observe that point to cannot be decided before the tables involved in a statement has been checked, i.e., we cannot put this code in reset_current_stmt_binlog_row_based(), it has to be here. */ if (thd->lex->is_stmt_unsafe() || (flags_all_set & HA_BINLOG_STMT_CAPABLE) == 0) { thd->set_current_stmt_binlog_row_based_if_mixed(); } } return 0; } /* Lock all tables in list SYNOPSIS lock_tables() thd Thread handler tables Tables to lock count Number of opened tables need_reopen Out parameter which if TRUE indicates that some tables were dropped or altered during this call and therefore invoker should reopen tables and try to lock them once again (in this case lock_tables() will also return error). NOTES You can't call lock_tables twice, as this would break the dead-lock-free handling thr_lock gives us. You most always get all needed locks at once. If query for which we are calling this function marked as requring prelocking, this function will do implicit LOCK TABLES and change thd::prelocked_mode accordingly. RETURN VALUES 0 ok -1 Error */ int lock_tables(THD *thd, TABLE_LIST *tables, uint count, bool *need_reopen) { TABLE_LIST *table; DBUG_ENTER("lock_tables"); /* We can't meet statement requiring prelocking if we already in prelocked mode. */ DBUG_ASSERT(!thd->prelocked_mode || !thd->lex->requires_prelocking()); *need_reopen= FALSE; if (!tables && !thd->lex->requires_prelocking()) DBUG_RETURN(decide_logging_format(thd, tables)); /* We need this extra check for thd->prelocked_mode because we want to avoid attempts to lock tables in substatements. Checking for thd->locked_tables is not enough in some situations. For example for SP containing "drop table t3; create temporary t3 ..; insert into t3 ...;" thd->locked_tables may be 0 after drop tables, and without this extra check insert will try to lock temporary table t3, that will lead to memory leak... */ if (!thd->locked_tables && !thd->prelocked_mode) { DBUG_ASSERT(thd->lock == 0); // You must lock everything at once TABLE **start,**ptr; uint lock_flag= MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN; if (!(ptr=start=(TABLE**) thd->alloc(sizeof(TABLE*)*count))) DBUG_RETURN(-1); for (table= tables; table; table= table->next_global) { if (!table->placeholder()) *(ptr++)= table->table; } /* We have to emulate LOCK TABLES if we are statement needs prelocking. */ if (thd->lex->requires_prelocking()) { thd->in_lock_tables=1; thd->options|= OPTION_TABLE_LOCK; /* If we have >= 2 different tables to update with auto_inc columns, statement-based binlogging won't work. We can solve this problem in mixed mode by switching to row-based binlogging: */ if (thd->variables.binlog_format == BINLOG_FORMAT_MIXED && has_two_write_locked_tables_with_auto_increment(tables)) { thd->lex->set_stmt_unsafe(); thd->set_current_stmt_binlog_row_based_if_mixed(); } } if (! (thd->lock= mysql_lock_tables(thd, start, (uint) (ptr - start), lock_flag, need_reopen))) { if (thd->lex->requires_prelocking()) { thd->options&= ~(OPTION_TABLE_LOCK); thd->in_lock_tables=0; } DBUG_RETURN(-1); } if (thd->lex->requires_prelocking() && thd->lex->sql_command != SQLCOM_LOCK_TABLES) { TABLE_LIST *first_not_own= thd->lex->first_not_own_table(); /* We just have done implicit LOCK TABLES, and now we have to emulate first open_and_lock_tables() after it. Note that "LOCK TABLES" can also be marked as requiring prelocking (e.g. if one locks view which uses functions). We should not emulate such open_and_lock_tables() in this case. We also should not set THD::prelocked_mode or first close_thread_tables() call will do "UNLOCK TABLES". */ thd->locked_tables= thd->lock; thd->lock= 0; thd->in_lock_tables=0; /* When open_and_lock_tables() is called for a single table out of a table list, the 'next_global' chain is temporarily broken. We may not find 'first_not_own' before the end of the "list". Look for example at those places where open_n_lock_single_table() is called. That function implements the temporary breaking of a table list for opening a single table. */ for (table= tables; table && table != first_not_own; table= table->next_global) { if (!table->placeholder()) { table->table->query_id= thd->query_id; if (check_lock_and_start_stmt(thd, table->table, table->lock_type)) { ha_rollback_stmt(thd); mysql_unlock_tables(thd, thd->locked_tables); thd->locked_tables= 0; thd->options&= ~(OPTION_TABLE_LOCK); DBUG_RETURN(-1); } } } /* Let us mark all tables which don't belong to the statement itself, and was marked as occupied during open_tables() as free for reuse. */ mark_real_tables_as_free_for_reuse(first_not_own); DBUG_PRINT("info",("prelocked_mode= PRELOCKED")); thd->prelocked_mode= PRELOCKED; } } else { TABLE_LIST *first_not_own= thd->lex->first_not_own_table(); /* When open_and_lock_tables() is called for a single table out of a table list, the 'next_global' chain is temporarily broken. We may not find 'first_not_own' before the end of the "list". Look for example at those places where open_n_lock_single_table() is called. That function implements the temporary breaking of a table list for opening a single table. */ for (table= tables; table && table != first_not_own; table= table->next_global) { if (!table->placeholder() && check_lock_and_start_stmt(thd, table->table, table->lock_type)) { ha_rollback_stmt(thd); DBUG_RETURN(-1); } } /* If we are under explicit LOCK TABLES and our statement requires prelocking, we should mark all "additional" tables as free for use and enter prelocked mode. */ if (thd->lex->requires_prelocking()) { mark_real_tables_as_free_for_reuse(first_not_own); DBUG_PRINT("info", ("thd->prelocked_mode= PRELOCKED_UNDER_LOCK_TABLES")); thd->prelocked_mode= PRELOCKED_UNDER_LOCK_TABLES; } } DBUG_RETURN(decide_logging_format(thd, tables)); } /* Prepare statement for reopening of tables and recalculation of set of prelocked tables. SYNOPSIS close_tables_for_reopen() thd in Thread context tables in/out List of tables which we were trying to open and lock */ void close_tables_for_reopen(THD *thd, TABLE_LIST **tables) { /* If table list consists only from tables from prelocking set, table list for new attempt should be empty, so we have to update list's root pointer. */ if (thd->lex->first_not_own_table() == *tables) *tables= 0; thd->lex->chop_off_not_own_tables(); sp_remove_not_own_routines(thd->lex); for (TABLE_LIST *tmp= *tables; tmp; tmp= tmp->next_global) tmp->table= 0; close_thread_tables(thd); } /* Open a single table without table caching and don't set it in open_list SYNPOSIS open_temporary_table() thd Thread object path Path (without .frm) db database table_name Table name link_in_list 1 if table should be linked into thd->temporary_tables NOTES: Used by alter_table to open a temporary table and when creating a temporary table with CREATE TEMPORARY ... RETURN 0 Error # TABLE object */ TABLE *open_temporary_table(THD *thd, const char *path, const char *db, const char *table_name, bool link_in_list) { TABLE *tmp_table; TABLE_SHARE *share; char cache_key[MAX_DBKEY_LENGTH], *saved_cache_key, *tmp_path; uint key_length; TABLE_LIST table_list; DBUG_ENTER("open_temporary_table"); DBUG_PRINT("enter", ("table: '%s'.'%s' path: '%s' server_id: %u " "pseudo_thread_id: %lu", db, table_name, path, (uint) thd->server_id, (ulong) thd->variables.pseudo_thread_id)); table_list.db= (char*) db; table_list.table_name= (char*) table_name; /* Create the cache_key for temporary tables */ key_length= create_table_def_key(thd, cache_key, &table_list, 1); if (!(tmp_table= (TABLE*) my_malloc(sizeof(*tmp_table) + sizeof(*share) + strlen(path)+1 + key_length, MYF(MY_WME)))) DBUG_RETURN(0); /* purecov: inspected */ share= (TABLE_SHARE*) (tmp_table+1); tmp_path= (char*) (share+1); saved_cache_key= strmov(tmp_path, path)+1; memcpy(saved_cache_key, cache_key, key_length); init_tmp_table_share(thd, share, saved_cache_key, key_length, strend(saved_cache_key)+1, tmp_path); if (open_table_def(thd, share, 0) || open_table_from_share(thd, share, table_name, (uint) (HA_OPEN_KEYFILE | HA_OPEN_RNDFILE | HA_GET_INDEX), READ_KEYINFO | COMPUTE_TYPES | EXTRA_RECORD, ha_open_options, tmp_table, FALSE)) { /* No need to lock share->mutex as this is not needed for tmp tables */ free_table_share(share); my_free((char*) tmp_table,MYF(0)); DBUG_RETURN(0); } tmp_table->reginfo.lock_type= TL_WRITE; // Simulate locked share->tmp_table= (tmp_table->file->has_transactions() ? TRANSACTIONAL_TMP_TABLE : NON_TRANSACTIONAL_TMP_TABLE); if (link_in_list) { /* growing temp list at the head */ tmp_table->next= thd->temporary_tables; if (tmp_table->next) tmp_table->next->prev= tmp_table; thd->temporary_tables= tmp_table; thd->temporary_tables->prev= 0; if (thd->slave_thread) slave_open_temp_tables++; } tmp_table->pos_in_table_list= 0; DBUG_PRINT("tmptable", ("opened table: '%s'.'%s' 0x%lx", tmp_table->s->db.str, tmp_table->s->table_name.str, (long) tmp_table)); DBUG_RETURN(tmp_table); } bool rm_temporary_table(handlerton *base, char *path) { bool error=0; handler *file; char *ext; DBUG_ENTER("rm_temporary_table"); strmov(ext= strend(path), reg_ext); if (my_delete(path,MYF(0))) error=1; /* purecov: inspected */ *ext= 0; // remove extension file= get_new_handler((TABLE_SHARE*) 0, current_thd->mem_root, base); if (file && file->ha_delete_table(path)) { error=1; sql_print_warning("Could not remove temporary table: '%s', error: %d", path, my_errno); } delete file; DBUG_RETURN(error); } /***************************************************************************** * The following find_field_in_XXX procedures implement the core of the * name resolution functionality. The entry point to resolve a column name in a * list of tables is 'find_field_in_tables'. It calls 'find_field_in_table_ref' * for each table reference. In turn, depending on the type of table reference, * 'find_field_in_table_ref' calls one of the 'find_field_in_XXX' procedures * below specific for the type of table reference. ******************************************************************************/ /* Special Field pointers as return values of find_field_in_XXX functions. */ Field *not_found_field= (Field*) 0x1; Field *view_ref_found= (Field*) 0x2; #define WRONG_GRANT (Field*) -1 static void update_field_dependencies(THD *thd, Field *field, TABLE *table) { DBUG_ENTER("update_field_dependencies"); if (thd->mark_used_columns != MARK_COLUMNS_NONE) { MY_BITMAP *current_bitmap; /* We always want to register the used keys, as the column bitmap may have been set for all fields (for example for view). */ table->covering_keys.intersect(field->part_of_key); table->merge_keys.merge(field->part_of_key); if (thd->mark_used_columns == MARK_COLUMNS_READ) current_bitmap= table->read_set; else current_bitmap= table->write_set; if (bitmap_fast_test_and_set(current_bitmap, field->field_index)) { if (thd->mark_used_columns == MARK_COLUMNS_WRITE) { DBUG_PRINT("warning", ("Found duplicated field")); thd->dup_field= field; } else { DBUG_PRINT("note", ("Field found before")); } DBUG_VOID_RETURN; } if (table->get_fields_in_item_tree) field->flags|= GET_FIXED_FIELDS_FLAG; table->used_fields++; } else if (table->get_fields_in_item_tree) field->flags|= GET_FIXED_FIELDS_FLAG; DBUG_VOID_RETURN; } /* Find a field by name in a view that uses merge algorithm. SYNOPSIS find_field_in_view() thd thread handler table_list view to search for 'name' name name of field length length of name item_name name of item if it will be created (VIEW) ref expression substituted in VIEW should be passed using this reference (return view_ref_found) register_tree_change TRUE if ref is not stack variable and we need register changes in item tree RETURN 0 field is not found view_ref_found found value in VIEW (real result is in *ref) # pointer to field - only for schema table fields */ static Field * find_field_in_view(THD *thd, TABLE_LIST *table_list, const char *name, uint length, const char *item_name, Item **ref, bool register_tree_change) { DBUG_ENTER("find_field_in_view"); DBUG_PRINT("enter", ("view: '%s', field name: '%s', item name: '%s', ref 0x%lx", table_list->alias, name, item_name, (ulong) ref)); Field_iterator_view field_it; field_it.set(table_list); Query_arena *arena= 0, backup; DBUG_ASSERT(table_list->schema_table_reformed || (ref != 0 && table_list->view != 0)); for (; !field_it.end_of_fields(); field_it.next()) { if (!my_strcasecmp(system_charset_info, field_it.name(), name)) { // in PS use own arena or data will be freed after prepare if (register_tree_change && thd->stmt_arena->is_stmt_prepare_or_first_sp_execute()) arena= thd->activate_stmt_arena_if_needed(&backup); /* create_item() may, or may not create a new Item, depending on the column reference. See create_view_field() for details. */ Item *item= field_it.create_item(thd); if (arena) thd->restore_active_arena(arena, &backup); if (!item) DBUG_RETURN(0); /* *ref != NULL means that *ref contains the item that we need to replace. If the item was aliased by the user, set the alias to the replacing item. We need to set alias on both ref itself and on ref real item. */ if (*ref && !(*ref)->is_autogenerated_name) { item->set_name((*ref)->name, (*ref)->name_length, system_charset_info); item->real_item()->set_name((*ref)->name, (*ref)->name_length, system_charset_info); } if (register_tree_change) thd->change_item_tree(ref, item); else *ref= item; DBUG_RETURN((Field*) view_ref_found); } } DBUG_RETURN(0); } /* Find field by name in a NATURAL/USING join table reference. SYNOPSIS find_field_in_natural_join() thd [in] thread handler table_ref [in] table reference to search name [in] name of field length [in] length of name ref [in/out] if 'name' is resolved to a view field, ref is set to point to the found view field register_tree_change [in] TRUE if ref is not stack variable and we need register changes in item tree actual_table [out] the original table reference where the field belongs - differs from 'table_list' only for NATURAL/USING joins DESCRIPTION Search for a field among the result fields of a NATURAL/USING join. Notice that this procedure is called only for non-qualified field names. In the case of qualified fields, we search directly the base tables of a natural join. RETURN NULL if the field was not found WRONG_GRANT if no access rights to the found field # Pointer to the found Field */ static Field * find_field_in_natural_join(THD *thd, TABLE_LIST *table_ref, const char *name, uint length, Item **ref, bool register_tree_change, TABLE_LIST **actual_table) { List_iterator_fast field_it(*(table_ref->join_columns)); Natural_join_column *nj_col, *curr_nj_col; Field *found_field; Query_arena *arena, backup; DBUG_ENTER("find_field_in_natural_join"); DBUG_PRINT("enter", ("field name: '%s', ref 0x%lx", name, (ulong) ref)); DBUG_ASSERT(table_ref->is_natural_join && table_ref->join_columns); DBUG_ASSERT(*actual_table == NULL); LINT_INIT(arena); LINT_INIT(found_field); for (nj_col= NULL, curr_nj_col= field_it++; curr_nj_col; curr_nj_col= field_it++) { if (!my_strcasecmp(system_charset_info, curr_nj_col->name(), name)) { if (nj_col) { my_error(ER_NON_UNIQ_ERROR, MYF(0), name, thd->where); DBUG_RETURN(NULL); } nj_col= curr_nj_col; } } if (!nj_col) DBUG_RETURN(NULL); if (nj_col->view_field) { Item *item; LINT_INIT(arena); if (register_tree_change) arena= thd->activate_stmt_arena_if_needed(&backup); /* create_item() may, or may not create a new Item, depending on the column reference. See create_view_field() for details. */ item= nj_col->create_item(thd); /* *ref != NULL means that *ref contains the item that we need to replace. If the item was aliased by the user, set the alias to the replacing item. We need to set alias on both ref itself and on ref real item. */ if (*ref && !(*ref)->is_autogenerated_name) { item->set_name((*ref)->name, (*ref)->name_length, system_charset_info); item->real_item()->set_name((*ref)->name, (*ref)->name_length, system_charset_info); } if (register_tree_change && arena) thd->restore_active_arena(arena, &backup); if (!item) DBUG_RETURN(NULL); DBUG_ASSERT(nj_col->table_field == NULL); if (nj_col->table_ref->schema_table_reformed) { /* Translation table items are always Item_fields and fixed already('mysql_schema_table' function). So we can return ->field. It is used only for 'show & where' commands. */ DBUG_RETURN(((Item_field*) (nj_col->view_field->item))->field); } if (register_tree_change) thd->change_item_tree(ref, item); else *ref= item; found_field= (Field*) view_ref_found; } else { /* This is a base table. */ DBUG_ASSERT(nj_col->view_field == NULL); DBUG_ASSERT(nj_col->table_ref->table == nj_col->table_field->table); found_field= nj_col->table_field; update_field_dependencies(thd, found_field, nj_col->table_ref->table); } *actual_table= nj_col->table_ref; DBUG_RETURN(found_field); } /* Find field by name in a base table or a view with temp table algorithm. SYNOPSIS find_field_in_table() thd thread handler table table where to search for the field name name of field length length of name allow_rowid do allow finding of "_rowid" field? cached_field_index_ptr cached position in field list (used to speedup lookup for fields in prepared tables) RETURN 0 field is not found # pointer to field */ Field * find_field_in_table(THD *thd, TABLE *table, const char *name, uint length, bool allow_rowid, uint *cached_field_index_ptr) { Field **field_ptr, *field; uint cached_field_index= *cached_field_index_ptr; DBUG_ENTER("find_field_in_table"); DBUG_PRINT("enter", ("table: '%s', field name: '%s'", table->alias, name)); /* We assume here that table->field < NO_CACHED_FIELD_INDEX = UINT_MAX */ if (cached_field_index < table->s->fields && !my_strcasecmp(system_charset_info, table->field[cached_field_index]->field_name, name)) field_ptr= table->field + cached_field_index; else if (table->s->name_hash.records) { field_ptr= (Field**) hash_search(&table->s->name_hash, (uchar*) name, length); if (field_ptr) { /* field_ptr points to field in TABLE_SHARE. Convert it to the matching field in table */ field_ptr= (table->field + (field_ptr - table->s->field)); } } else { if (!(field_ptr= table->field)) DBUG_RETURN((Field *)0); for (; *field_ptr; ++field_ptr) if (!my_strcasecmp(system_charset_info, (*field_ptr)->field_name, name)) break; } if (field_ptr && *field_ptr) { *cached_field_index_ptr= field_ptr - table->field; field= *field_ptr; } else { if (!allow_rowid || my_strcasecmp(system_charset_info, name, "_rowid") || table->s->rowid_field_offset == 0) DBUG_RETURN((Field*) 0); field= table->field[table->s->rowid_field_offset-1]; } update_field_dependencies(thd, field, table); DBUG_RETURN(field); } /* Find field in a table reference. SYNOPSIS find_field_in_table_ref() thd [in] thread handler table_list [in] table reference to search name [in] name of field length [in] field length of name item_name [in] name of item if it will be created (VIEW) db_name [in] optional database name that qualifies the table_name [in] optional table name that qualifies the field ref [in/out] if 'name' is resolved to a view field, ref is set to point to the found view field check_privileges [in] check privileges allow_rowid [in] do allow finding of "_rowid" field? cached_field_index_ptr [in] cached position in field list (used to speedup lookup for fields in prepared tables) register_tree_change [in] TRUE if ref is not stack variable and we need register changes in item tree actual_table [out] the original table reference where the field belongs - differs from 'table_list' only for NATURAL_USING joins. DESCRIPTION Find a field in a table reference depending on the type of table reference. There are three types of table references with respect to the representation of their result columns: - an array of Field_translator objects for MERGE views and some information_schema tables, - an array of Field objects (and possibly a name hash) for stored tables, - a list of Natural_join_column objects for NATURAL/USING joins. This procedure detects the type of the table reference 'table_list' and calls the corresponding search routine. RETURN 0 field is not found view_ref_found found value in VIEW (real result is in *ref) # pointer to field */ Field * find_field_in_table_ref(THD *thd, TABLE_LIST *table_list, const char *name, uint length, const char *item_name, const char *db_name, const char *table_name, Item **ref, bool check_privileges, bool allow_rowid, uint *cached_field_index_ptr, bool register_tree_change, TABLE_LIST **actual_table) { Field *fld; DBUG_ENTER("find_field_in_table_ref"); DBUG_ASSERT(table_list->alias); DBUG_ASSERT(name); DBUG_ASSERT(item_name); DBUG_PRINT("enter", ("table: '%s' field name: '%s' item name: '%s' ref 0x%lx", table_list->alias, name, item_name, (ulong) ref)); /* Check that the table and database that qualify the current field name are the same as the table reference we are going to search for the field. Exclude from the test below nested joins because the columns in a nested join generally originate from different tables. Nested joins also have no table name, except when a nested join is a merge view or an information schema table. We include explicitly table references with a 'field_translation' table, because if there are views over natural joins we don't want to search inside the view, but we want to search directly in the view columns which are represented as a 'field_translation'. TODO: Ensure that table_name, db_name and tables->db always points to something ! */ if (/* Exclude nested joins. */ (!table_list->nested_join || /* Include merge views and information schema tables. */ table_list->field_translation) && /* Test if the field qualifiers match the table reference we plan to search. */ table_name && table_name[0] && (my_strcasecmp(table_alias_charset, table_list->alias, table_name) || (db_name && db_name[0] && table_list->db && table_list->db[0] && strcmp(db_name, table_list->db)))) DBUG_RETURN(0); *actual_table= NULL; if (table_list->field_translation) { /* 'table_list' is a view or an information schema table. */ if ((fld= find_field_in_view(thd, table_list, name, length, item_name, ref, register_tree_change))) *actual_table= table_list; } else if (!table_list->nested_join) { /* 'table_list' is a stored table. */ DBUG_ASSERT(table_list->table); if ((fld= find_field_in_table(thd, table_list->table, name, length, allow_rowid, cached_field_index_ptr))) *actual_table= table_list; } else { /* 'table_list' is a NATURAL/USING join, or an operand of such join that is a nested join itself. If the field name we search for is qualified, then search for the field in the table references used by NATURAL/USING the join. */ if (table_name && table_name[0]) { List_iterator it(table_list->nested_join->join_list); TABLE_LIST *table; while ((table= it++)) { if ((fld= find_field_in_table_ref(thd, table, name, length, item_name, db_name, table_name, ref, check_privileges, allow_rowid, cached_field_index_ptr, register_tree_change, actual_table))) DBUG_RETURN(fld); } DBUG_RETURN(0); } /* Non-qualified field, search directly in the result columns of the natural join. The condition of the outer IF is true for the top-most natural join, thus if the field is not qualified, we will search directly the top-most NATURAL/USING join. */ fld= find_field_in_natural_join(thd, table_list, name, length, ref, register_tree_change, actual_table); } if (fld) { #ifndef NO_EMBEDDED_ACCESS_CHECKS /* Check if there are sufficient access rights to the found field. */ if (check_privileges && check_column_grant_in_table_ref(thd, *actual_table, name, length)) fld= WRONG_GRANT; else #endif if (thd->mark_used_columns != MARK_COLUMNS_NONE) { /* Get rw_set correct for this field so that the handler knows that this field is involved in the query and gets retrieved/updated */ Field *field_to_set= NULL; if (fld == view_ref_found) { Item *it= (*ref)->real_item(); if (it->type() == Item::FIELD_ITEM) field_to_set= ((Item_field*)it)->field; else { if (thd->mark_used_columns == MARK_COLUMNS_READ) it->walk(&Item::register_field_in_read_map, 1, (uchar *) 0); } } else field_to_set= fld; if (field_to_set) { TABLE *table= field_to_set->table; if (thd->mark_used_columns == MARK_COLUMNS_READ) bitmap_set_bit(table->read_set, field_to_set->field_index); else bitmap_set_bit(table->write_set, field_to_set->field_index); } } } DBUG_RETURN(fld); } /* Find field in table, no side effects, only purpose is to check for field in table object and get reference to the field if found. SYNOPSIS find_field_in_table_sef() table table where to find name Name of field searched for RETURN 0 field is not found # pointer to field */ Field *find_field_in_table_sef(TABLE *table, const char *name) { Field **field_ptr; if (table->s->name_hash.records) { field_ptr= (Field**)hash_search(&table->s->name_hash,(uchar*) name, strlen(name)); if (field_ptr) { /* field_ptr points to field in TABLE_SHARE. Convert it to the matching field in table */ field_ptr= (table->field + (field_ptr - table->s->field)); } } else { if (!(field_ptr= table->field)) return (Field *)0; for (; *field_ptr; ++field_ptr) if (!my_strcasecmp(system_charset_info, (*field_ptr)->field_name, name)) break; } if (field_ptr) return *field_ptr; else return (Field *)0; } /* Find field in table list. SYNOPSIS find_field_in_tables() thd pointer to current thread structure item field item that should be found first_table list of tables to be searched for item last_table end of the list of tables to search for item. If NULL then search to the end of the list 'first_table'. ref if 'item' is resolved to a view field, ref is set to point to the found view field report_error Degree of error reporting: - IGNORE_ERRORS then do not report any error - IGNORE_EXCEPT_NON_UNIQUE report only non-unique fields, suppress all other errors - REPORT_EXCEPT_NON_UNIQUE report all other errors except when non-unique fields were found - REPORT_ALL_ERRORS check_privileges need to check privileges register_tree_change TRUE if ref is not a stack variable and we to need register changes in item tree RETURN VALUES 0 If error: the found field is not unique, or there are no sufficient access priviliges for the found field, or the field is qualified with non-existing table. not_found_field The function was called with report_error == (IGNORE_ERRORS || IGNORE_EXCEPT_NON_UNIQUE) and a field was not found. view_ref_found View field is found, item passed through ref parameter found field If a item was resolved to some field */ Field * find_field_in_tables(THD *thd, Item_ident *item, TABLE_LIST *first_table, TABLE_LIST *last_table, Item **ref, find_item_error_report_type report_error, bool check_privileges, bool register_tree_change) { Field *found=0; const char *db= item->db_name; const char *table_name= item->table_name; const char *name= item->field_name; uint length=(uint) strlen(name); char name_buff[NAME_LEN+1]; TABLE_LIST *cur_table= first_table; TABLE_LIST *actual_table; bool allow_rowid; if (!table_name || !table_name[0]) { table_name= 0; // For easier test db= 0; } allow_rowid= table_name || (cur_table && !cur_table->next_local); if (item->cached_table) { /* This shortcut is used by prepared statements. We assume that TABLE_LIST *first_table is not changed during query execution (which is true for all queries except RENAME but luckily RENAME doesn't use fields...) so we can rely on reusing pointer to its member. With this optimization we also miss case when addition of one more field makes some prepared query ambiguous and so erroneous, but we accept this trade off. */ TABLE_LIST *table_ref= item->cached_table; /* The condition (table_ref->view == NULL) ensures that we will call find_field_in_table even in the case of information schema tables when table_ref->field_translation != NULL. */ if (table_ref->table && !table_ref->view) found= find_field_in_table(thd, table_ref->table, name, length, TRUE, &(item->cached_field_index)); else found= find_field_in_table_ref(thd, table_ref, name, length, item->name, NULL, NULL, ref, check_privileges, TRUE, &(item->cached_field_index), register_tree_change, &actual_table); if (found) { if (found == WRONG_GRANT) return (Field*) 0; /* Only views fields should be marked as dependent, not an underlying fields. */ if (!table_ref->belong_to_view) { SELECT_LEX *current_sel= thd->lex->current_select; SELECT_LEX *last_select= table_ref->select_lex; /* If the field was an outer referencee, mark all selects using this sub query as dependent on the outer query */ if (current_sel != last_select) mark_select_range_as_dependent(thd, last_select, current_sel, found, *ref, item); } return found; } } if (db && lower_case_table_names) { /* convert database to lower case for comparison. We can't do this in Item_field as this would change the 'name' of the item which may be used in the select list */ strmake(name_buff, db, sizeof(name_buff)-1); my_casedn_str(files_charset_info, name_buff); db= name_buff; } if (last_table) last_table= last_table->next_name_resolution_table; for (; cur_table != last_table ; cur_table= cur_table->next_name_resolution_table) { Field *cur_field= find_field_in_table_ref(thd, cur_table, name, length, item->name, db, table_name, ref, (thd->lex->sql_command == SQLCOM_SHOW_FIELDS) ? false : check_privileges, allow_rowid, &(item->cached_field_index), register_tree_change, &actual_table); if (cur_field) { if (cur_field == WRONG_GRANT) { if (thd->lex->sql_command != SQLCOM_SHOW_FIELDS) return (Field*) 0; thd->clear_error(); cur_field= find_field_in_table_ref(thd, cur_table, name, length, item->name, db, table_name, ref, false, allow_rowid, &(item->cached_field_index), register_tree_change, &actual_table); if (cur_field) { Field *nf=new Field_null(NULL,0,Field::NONE, cur_field->field_name, &my_charset_bin); nf->init(cur_table->table); cur_field= nf; } } /* Store the original table of the field, which may be different from cur_table in the case of NATURAL/USING join. */ item->cached_table= (!actual_table->cacheable_table || found) ? 0 : actual_table; DBUG_ASSERT(thd->where); /* If we found a fully qualified field we return it directly as it can't have duplicates. */ if (db) return cur_field; if (found) { if (report_error == REPORT_ALL_ERRORS || report_error == IGNORE_EXCEPT_NON_UNIQUE) my_error(ER_NON_UNIQ_ERROR, MYF(0), table_name ? item->full_name() : name, thd->where); return (Field*) 0; } found= cur_field; } } if (found) return found; /* If the field was qualified and there were no tables to search, issue an error that an unknown table was given. The situation is detected as follows: if there were no tables we wouldn't go through the loop and cur_table wouldn't be updated by the loop increment part, so it will be equal to the first table. */ if (table_name && (cur_table == first_table) && (report_error == REPORT_ALL_ERRORS || report_error == REPORT_EXCEPT_NON_UNIQUE)) { char buff[NAME_LEN*2+1]; if (db && db[0]) { strxnmov(buff,sizeof(buff)-1,db,".",table_name,NullS); table_name=buff; } my_error(ER_UNKNOWN_TABLE, MYF(0), table_name, thd->where); } else { if (report_error == REPORT_ALL_ERRORS || report_error == REPORT_EXCEPT_NON_UNIQUE) my_error(ER_BAD_FIELD_ERROR, MYF(0), item->full_name(), thd->where); else found= not_found_field; } return found; } /* Find Item in list of items (find_field_in_tables analog) TODO is it better return only counter? SYNOPSIS find_item_in_list() find Item to find items List of items counter To return number of found item report_error REPORT_ALL_ERRORS report errors, return 0 if error REPORT_EXCEPT_NOT_FOUND Do not report 'not found' error and return not_found_item, report other errors, return 0 IGNORE_ERRORS Do not report errors, return 0 if error resolution Set to the resolution type if the item is found (it says whether the item is resolved against an alias name, or as a field name without alias, or as a field hidden by alias, or ignoring alias) RETURN VALUES 0 Item is not found or item is not unique, error message is reported not_found_item Function was called with report_error == REPORT_EXCEPT_NOT_FOUND and item was not found. No error message was reported found field */ /* Special Item pointer to serve as a return value from find_item_in_list(). */ Item **not_found_item= (Item**) 0x1; Item ** find_item_in_list(Item *find, List &items, uint *counter, find_item_error_report_type report_error, enum_resolution_type *resolution) { List_iterator li(items); Item **found=0, **found_unaliased= 0, *item; const char *db_name=0; const char *field_name=0; const char *table_name=0; bool found_unaliased_non_uniq= 0; /* true if the item that we search for is a valid name reference (and not an item that happens to have a name). */ bool is_ref_by_name= 0; uint unaliased_counter; LINT_INIT(unaliased_counter); // Dependent on found_unaliased *resolution= NOT_RESOLVED; is_ref_by_name= (find->type() == Item::FIELD_ITEM || find->type() == Item::REF_ITEM); if (is_ref_by_name) { field_name= ((Item_ident*) find)->field_name; table_name= ((Item_ident*) find)->table_name; db_name= ((Item_ident*) find)->db_name; } for (uint i= 0; (item=li++); i++) { if (field_name && item->real_item()->type() == Item::FIELD_ITEM) { Item_ident *item_field= (Item_ident*) item; /* In case of group_concat() with ORDER BY condition in the QUERY item_field can be field of temporary table without item name (if this field created from expression argument of group_concat()), => we have to check presence of name before compare */ if (!item_field->name) continue; if (table_name) { /* If table name is specified we should find field 'field_name' in table 'table_name'. According to SQL-standard we should ignore aliases in this case. Since we should NOT prefer fields from the select list over other fields from the tables participating in this select in case of ambiguity we have to do extra check outside this function. We use strcmp for table names and database names as these may be case sensitive. In cases where they are not case sensitive, they are always in lower case. item_field->field_name and item_field->table_name can be 0x0 if item is not fix_field()'ed yet. */ if (item_field->field_name && item_field->table_name && !my_strcasecmp(system_charset_info, item_field->field_name, field_name) && !my_strcasecmp(table_alias_charset, item_field->table_name, table_name) && (!db_name || (item_field->db_name && !strcmp(item_field->db_name, db_name)))) { if (found_unaliased) { if ((*found_unaliased)->eq(item, 0)) continue; /* Two matching fields in select list. We already can bail out because we are searching through unaliased names only and will have duplicate error anyway. */ if (report_error != IGNORE_ERRORS) my_error(ER_NON_UNIQ_ERROR, MYF(0), find->full_name(), current_thd->where); return (Item**) 0; } found_unaliased= li.ref(); unaliased_counter= i; *resolution= RESOLVED_IGNORING_ALIAS; if (db_name) break; // Perfect match } } else { int fname_cmp= my_strcasecmp(system_charset_info, item_field->field_name, field_name); if (!my_strcasecmp(system_charset_info, item_field->name,field_name)) { /* If table name was not given we should scan through aliases and non-aliased fields first. We are also checking unaliased name of the field in then next else-if, to be able to find instantly field (hidden by alias) if no suitable alias or non-aliased field was found. */ if (found) { if ((*found)->eq(item, 0)) continue; // Same field twice if (report_error != IGNORE_ERRORS) my_error(ER_NON_UNIQ_ERROR, MYF(0), find->full_name(), current_thd->where); return (Item**) 0; } found= li.ref(); *counter= i; *resolution= fname_cmp ? RESOLVED_AGAINST_ALIAS: RESOLVED_WITH_NO_ALIAS; } else if (!fname_cmp) { /* We will use non-aliased field or react on such ambiguities only if we won't be able to find aliased field. Again if we have ambiguity with field outside of select list we should prefer fields from select list. */ if (found_unaliased) { if ((*found_unaliased)->eq(item, 0)) continue; // Same field twice found_unaliased_non_uniq= 1; } found_unaliased= li.ref(); unaliased_counter= i; } } } else if (!table_name) { if (is_ref_by_name && find->name && item->name && !my_strcasecmp(system_charset_info,item->name,find->name)) { found= li.ref(); *counter= i; *resolution= RESOLVED_AGAINST_ALIAS; break; } else if (find->eq(item,0)) { found= li.ref(); *counter= i; *resolution= RESOLVED_IGNORING_ALIAS; break; } } else if (table_name && item->type() == Item::REF_ITEM && ((Item_ref *)item)->ref_type() == Item_ref::VIEW_REF) { /* TODO:Here we process prefixed view references only. What we should really do is process all types of Item_refs. But this will currently lead to a clash with the way references to outer SELECTs (from the HAVING clause) are handled in e.g. : SELECT 1 FROM t1 AS t1_o GROUP BY a HAVING (SELECT t1_o.a FROM t1 AS t1_i GROUP BY t1_i.a LIMIT 1). Processing all Item_refs here will cause t1_o.a to resolve to itself. We still need to process the special case of Item_direct_view_ref because in the context of views they have the same meaning as Item_field for tables. */ Item_ident *item_ref= (Item_ident *) item; if (item_ref->name && item_ref->table_name && !my_strcasecmp(system_charset_info, item_ref->name, field_name) && !my_strcasecmp(table_alias_charset, item_ref->table_name, table_name) && (!db_name || (item_ref->db_name && !strcmp (item_ref->db_name, db_name)))) { found= li.ref(); *counter= i; *resolution= RESOLVED_IGNORING_ALIAS; break; } } } if (!found) { if (found_unaliased_non_uniq) { if (report_error != IGNORE_ERRORS) my_error(ER_NON_UNIQ_ERROR, MYF(0), find->full_name(), current_thd->where); return (Item **) 0; } if (found_unaliased) { found= found_unaliased; *counter= unaliased_counter; *resolution= RESOLVED_BEHIND_ALIAS; } } if (found) return found; if (report_error != REPORT_EXCEPT_NOT_FOUND) { if (report_error == REPORT_ALL_ERRORS) my_error(ER_BAD_FIELD_ERROR, MYF(0), find->full_name(), current_thd->where); return (Item **) 0; } else return (Item **) not_found_item; } /* Test if a string is a member of a list of strings. SYNOPSIS test_if_string_in_list() find the string to look for str_list a list of strings to be searched DESCRIPTION Sequentially search a list of strings for a string, and test whether the list contains the same string. RETURN TRUE if find is in str_list FALSE otherwise */ static bool test_if_string_in_list(const char *find, List *str_list) { List_iterator str_list_it(*str_list); String *curr_str; size_t find_length= strlen(find); while ((curr_str= str_list_it++)) { if (find_length != curr_str->length()) continue; if (!my_strcasecmp(system_charset_info, find, curr_str->ptr())) return TRUE; } return FALSE; } /* Create a new name resolution context for an item so that it is being resolved in a specific table reference. SYNOPSIS set_new_item_local_context() thd pointer to current thread item item for which new context is created and set table_ref table ref where an item showld be resolved DESCRIPTION Create a new name resolution context for an item, so that the item is resolved only the supplied 'table_ref'. RETURN FALSE if all OK TRUE otherwise */ static bool set_new_item_local_context(THD *thd, Item_ident *item, TABLE_LIST *table_ref) { Name_resolution_context *context; if (!(context= new (thd->mem_root) Name_resolution_context)) return TRUE; context->init(); context->first_name_resolution_table= context->last_name_resolution_table= table_ref; item->context= context; return FALSE; } /* Find and mark the common columns of two table references. SYNOPSIS mark_common_columns() thd [in] current thread table_ref_1 [in] the first (left) join operand table_ref_2 [in] the second (right) join operand using_fields [in] if the join is JOIN...USING - the join columns, if NATURAL join, then NULL found_using_fields [out] number of fields from the USING clause that were found among the common fields DESCRIPTION The procedure finds the common columns of two relations (either tables or intermediate join results), and adds an equi-join condition to the ON clause of 'table_ref_2' for each pair of matching columns. If some of table_ref_XXX represents a base table or view, then we create new 'Natural_join_column' instances for each column reference and store them in the 'join_columns' of the table reference. IMPLEMENTATION The procedure assumes that store_natural_using_join_columns() was called for the previous level of NATURAL/USING joins. RETURN TRUE error when some common column is non-unique, or out of memory FALSE OK */ static bool mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2, List *using_fields, uint *found_using_fields) { Field_iterator_table_ref it_1, it_2; Natural_join_column *nj_col_1, *nj_col_2; Query_arena *arena, backup; bool result= TRUE; bool first_outer_loop= TRUE; /* Leaf table references to which new natural join columns are added if the leaves are != NULL. */ TABLE_LIST *leaf_1= (table_ref_1->nested_join && !table_ref_1->is_natural_join) ? NULL : table_ref_1; TABLE_LIST *leaf_2= (table_ref_2->nested_join && !table_ref_2->is_natural_join) ? NULL : table_ref_2; DBUG_ENTER("mark_common_columns"); DBUG_PRINT("info", ("operand_1: %s operand_2: %s", table_ref_1->alias, table_ref_2->alias)); *found_using_fields= 0; arena= thd->activate_stmt_arena_if_needed(&backup); for (it_1.set(table_ref_1); !it_1.end_of_fields(); it_1.next()) { bool found= FALSE; const char *field_name_1; /* true if field_name_1 is a member of using_fields */ bool is_using_column_1; if (!(nj_col_1= it_1.get_or_create_column_ref(leaf_1))) goto err; field_name_1= nj_col_1->name(); is_using_column_1= using_fields && test_if_string_in_list(field_name_1, using_fields); DBUG_PRINT ("info", ("field_name_1=%s.%s", nj_col_1->table_name() ? nj_col_1->table_name() : "", field_name_1)); /* Find a field with the same name in table_ref_2. Note that for the second loop, it_2.set() will iterate over table_ref_2->join_columns and not generate any new elements or lists. */ nj_col_2= NULL; for (it_2.set(table_ref_2); !it_2.end_of_fields(); it_2.next()) { Natural_join_column *cur_nj_col_2; const char *cur_field_name_2; if (!(cur_nj_col_2= it_2.get_or_create_column_ref(leaf_2))) goto err; cur_field_name_2= cur_nj_col_2->name(); DBUG_PRINT ("info", ("cur_field_name_2=%s.%s", cur_nj_col_2->table_name() ? cur_nj_col_2->table_name() : "", cur_field_name_2)); /* Compare the two columns and check for duplicate common fields. A common field is duplicate either if it was already found in table_ref_2 (then found == TRUE), or if a field in table_ref_2 was already matched by some previous field in table_ref_1 (then cur_nj_col_2->is_common == TRUE). Note that it is too early to check the columns outside of the USING list for ambiguity because they are not actually "referenced" here. These columns must be checked only on unqualified reference by name (e.g. in SELECT list). */ if (!my_strcasecmp(system_charset_info, field_name_1, cur_field_name_2)) { DBUG_PRINT ("info", ("match c1.is_common=%d", nj_col_1->is_common)); if (cur_nj_col_2->is_common || (found && (!using_fields || is_using_column_1))) { my_error(ER_NON_UNIQ_ERROR, MYF(0), field_name_1, thd->where); goto err; } nj_col_2= cur_nj_col_2; found= TRUE; } } if (first_outer_loop && leaf_2) { /* Make sure that the next inner loop "knows" that all columns are materialized already. */ leaf_2->is_join_columns_complete= TRUE; first_outer_loop= FALSE; } if (!found) continue; // No matching field /* field_1 and field_2 have the same names. Check if they are in the USING clause (if present), mark them as common fields, and add a new equi-join condition to the ON clause. */ if (nj_col_2 && (!using_fields ||is_using_column_1)) { Item *item_1= nj_col_1->create_item(thd); Item *item_2= nj_col_2->create_item(thd); Field *field_1= nj_col_1->field(); Field *field_2= nj_col_2->field(); Item_ident *item_ident_1, *item_ident_2; Item_func_eq *eq_cond; if (!item_1 || !item_2) goto err; // out of memory /* The following assert checks that the two created items are of type Item_ident. */ DBUG_ASSERT(!thd->lex->current_select->no_wrap_view_item); /* In the case of no_wrap_view_item == 0, the created items must be of sub-classes of Item_ident. */ DBUG_ASSERT(item_1->type() == Item::FIELD_ITEM || item_1->type() == Item::REF_ITEM); DBUG_ASSERT(item_2->type() == Item::FIELD_ITEM || item_2->type() == Item::REF_ITEM); /* We need to cast item_1,2 to Item_ident, because we need to hook name resolution contexts specific to each item. */ item_ident_1= (Item_ident*) item_1; item_ident_2= (Item_ident*) item_2; /* Create and hook special name resolution contexts to each item in the new join condition . We need this to both speed-up subsequent name resolution of these items, and to enable proper name resolution of the items during the execute phase of PS. */ if (set_new_item_local_context(thd, item_ident_1, nj_col_1->table_ref) || set_new_item_local_context(thd, item_ident_2, nj_col_2->table_ref)) goto err; if (!(eq_cond= new Item_func_eq(item_ident_1, item_ident_2))) goto err; /* Out of memory. */ /* Add the new equi-join condition to the ON clause. Notice that fix_fields() is applied to all ON conditions in setup_conds() so we don't do it here. */ add_join_on((table_ref_1->outer_join & JOIN_TYPE_RIGHT ? table_ref_1 : table_ref_2), eq_cond); nj_col_1->is_common= nj_col_2->is_common= TRUE; DBUG_PRINT ("info", ("%s.%s and %s.%s are common", nj_col_1->table_name() ? nj_col_1->table_name() : "", nj_col_1->name(), nj_col_2->table_name() ? nj_col_2->table_name() : "", nj_col_2->name())); if (field_1) { TABLE *table_1= nj_col_1->table_ref->table; /* Mark field_1 used for table cache. */ bitmap_set_bit(table_1->read_set, field_1->field_index); table_1->covering_keys.intersect(field_1->part_of_key); table_1->merge_keys.merge(field_1->part_of_key); } if (field_2) { TABLE *table_2= nj_col_2->table_ref->table; /* Mark field_2 used for table cache. */ bitmap_set_bit(table_2->read_set, field_2->field_index); table_2->covering_keys.intersect(field_2->part_of_key); table_2->merge_keys.merge(field_2->part_of_key); } if (using_fields != NULL) ++(*found_using_fields); } } if (leaf_1) leaf_1->is_join_columns_complete= TRUE; /* Everything is OK. Notice that at this point there may be some column names in the USING clause that are not among the common columns. This is an SQL error and we check for this error in store_natural_using_join_columns() when (found_using_fields < length(join_using_fields)). */ result= FALSE; err: if (arena) thd->restore_active_arena(arena, &backup); DBUG_RETURN(result); } /* Materialize and store the row type of NATURAL/USING join. SYNOPSIS store_natural_using_join_columns() thd current thread natural_using_join the table reference of the NATURAL/USING join table_ref_1 the first (left) operand (of a NATURAL/USING join). table_ref_2 the second (right) operand (of a NATURAL/USING join). using_fields if the join is JOIN...USING - the join columns, if NATURAL join, then NULL found_using_fields number of fields from the USING clause that were found among the common fields DESCRIPTION Iterate over the columns of both join operands and sort and store all columns into the 'join_columns' list of natural_using_join where the list is formed by three parts: part1: The coalesced columns of table_ref_1 and table_ref_2, sorted according to the column order of the first table. part2: The other columns of the first table, in the order in which they were defined in CREATE TABLE. part3: The other columns of the second table, in the order in which they were defined in CREATE TABLE. Time complexity - O(N1+N2), where Ni = length(table_ref_i). IMPLEMENTATION The procedure assumes that mark_common_columns() has been called for the join that is being processed. RETURN TRUE error: Some common column is ambiguous FALSE OK */ static bool store_natural_using_join_columns(THD *thd, TABLE_LIST *natural_using_join, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2, List *using_fields, uint found_using_fields) { Field_iterator_table_ref it_1, it_2; Natural_join_column *nj_col_1, *nj_col_2; Query_arena *arena, backup; bool result= TRUE; List *non_join_columns; DBUG_ENTER("store_natural_using_join_columns"); DBUG_ASSERT(!natural_using_join->join_columns); arena= thd->activate_stmt_arena_if_needed(&backup); if (!(non_join_columns= new List) || !(natural_using_join->join_columns= new List)) goto err; /* Append the columns of the first join operand. */ for (it_1.set(table_ref_1); !it_1.end_of_fields(); it_1.next()) { nj_col_1= it_1.get_natural_column_ref(); if (nj_col_1->is_common) { natural_using_join->join_columns->push_back(nj_col_1); /* Reset the common columns for the next call to mark_common_columns. */ nj_col_1->is_common= FALSE; } else non_join_columns->push_back(nj_col_1); } /* Check that all columns in the USING clause are among the common columns. If this is not the case, report the first one that was not found in an error. */ if (using_fields && found_using_fields < using_fields->elements) { String *using_field_name; List_iterator_fast using_fields_it(*using_fields); while ((using_field_name= using_fields_it++)) { const char *using_field_name_ptr= using_field_name->c_ptr(); List_iterator_fast it(*(natural_using_join->join_columns)); Natural_join_column *common_field; for (;;) { /* If reached the end of fields, and none was found, report error. */ if (!(common_field= it++)) { my_error(ER_BAD_FIELD_ERROR, MYF(0), using_field_name_ptr, current_thd->where); goto err; } if (!my_strcasecmp(system_charset_info, common_field->name(), using_field_name_ptr)) break; // Found match } } } /* Append the non-equi-join columns of the second join operand. */ for (it_2.set(table_ref_2); !it_2.end_of_fields(); it_2.next()) { nj_col_2= it_2.get_natural_column_ref(); if (!nj_col_2->is_common) non_join_columns->push_back(nj_col_2); else { /* Reset the common columns for the next call to mark_common_columns. */ nj_col_2->is_common= FALSE; } } if (non_join_columns->elements > 0) natural_using_join->join_columns->concat(non_join_columns); natural_using_join->is_join_columns_complete= TRUE; result= FALSE; err: if (arena) thd->restore_active_arena(arena, &backup); DBUG_RETURN(result); } /* Precompute and store the row types of the top-most NATURAL/USING joins. SYNOPSIS store_top_level_join_columns() thd current thread table_ref nested join or table in a FROM clause left_neighbor neighbor table reference to the left of table_ref at the same level in the join tree right_neighbor neighbor table reference to the right of table_ref at the same level in the join tree DESCRIPTION The procedure performs a post-order traversal of a nested join tree and materializes the row types of NATURAL/USING joins in a bottom-up manner until it reaches the TABLE_LIST elements that represent the top-most NATURAL/USING joins. The procedure should be applied to each element of SELECT_LEX::top_join_list (i.e. to each top-level element of the FROM clause). IMPLEMENTATION Notice that the table references in the list nested_join->join_list are in reverse order, thus when we iterate over it, we are moving from the right to the left in the FROM clause. RETURN TRUE Error FALSE OK */ static bool store_top_level_join_columns(THD *thd, TABLE_LIST *table_ref, TABLE_LIST *left_neighbor, TABLE_LIST *right_neighbor) { Query_arena *arena, backup; bool result= TRUE; DBUG_ENTER("store_top_level_join_columns"); arena= thd->activate_stmt_arena_if_needed(&backup); /* Call the procedure recursively for each nested table reference. */ if (table_ref->nested_join) { List_iterator_fast nested_it(table_ref->nested_join->join_list); TABLE_LIST *same_level_left_neighbor= nested_it++; TABLE_LIST *same_level_right_neighbor= NULL; /* Left/right-most neighbors, possibly at higher levels in the join tree. */ TABLE_LIST *real_left_neighbor, *real_right_neighbor; while (same_level_left_neighbor) { TABLE_LIST *cur_table_ref= same_level_left_neighbor; same_level_left_neighbor= nested_it++; /* The order of RIGHT JOIN operands is reversed in 'join list' to transform it into a LEFT JOIN. However, in this procedure we need the join operands in their lexical order, so below we reverse the join operands. Notice that this happens only in the first loop, and not in the second one, as in the second loop same_level_left_neighbor == NULL. This is the correct behavior, because the second loop sets cur_table_ref reference correctly after the join operands are swapped in the first loop. */ if (same_level_left_neighbor && cur_table_ref->outer_join & JOIN_TYPE_RIGHT) { /* This can happen only for JOIN ... ON. */ DBUG_ASSERT(table_ref->nested_join->join_list.elements == 2); swap_variables(TABLE_LIST*, same_level_left_neighbor, cur_table_ref); } /* Pick the parent's left and right neighbors if there are no immediate neighbors at the same level. */ real_left_neighbor= (same_level_left_neighbor) ? same_level_left_neighbor : left_neighbor; real_right_neighbor= (same_level_right_neighbor) ? same_level_right_neighbor : right_neighbor; if (cur_table_ref->nested_join && store_top_level_join_columns(thd, cur_table_ref, real_left_neighbor, real_right_neighbor)) goto err; same_level_right_neighbor= cur_table_ref; } } /* If this is a NATURAL/USING join, materialize its result columns and convert to a JOIN ... ON. */ if (table_ref->is_natural_join) { DBUG_ASSERT(table_ref->nested_join && table_ref->nested_join->join_list.elements == 2); List_iterator_fast operand_it(table_ref->nested_join->join_list); /* Notice that the order of join operands depends on whether table_ref represents a LEFT or a RIGHT join. In a RIGHT join, the operands are in inverted order. */ TABLE_LIST *table_ref_2= operand_it++; /* Second NATURAL join operand.*/ TABLE_LIST *table_ref_1= operand_it++; /* First NATURAL join operand. */ List *using_fields= table_ref->join_using_fields; uint found_using_fields; /* The two join operands were interchanged in the parser, change the order back for 'mark_common_columns'. */ if (table_ref_2->outer_join & JOIN_TYPE_RIGHT) swap_variables(TABLE_LIST*, table_ref_1, table_ref_2); if (mark_common_columns(thd, table_ref_1, table_ref_2, using_fields, &found_using_fields)) goto err; /* Swap the join operands back, so that we pick the columns of the second one as the coalesced columns. In this way the coalesced columns are the same as of an equivalent LEFT JOIN. */ if (table_ref_1->outer_join & JOIN_TYPE_RIGHT) swap_variables(TABLE_LIST*, table_ref_1, table_ref_2); if (store_natural_using_join_columns(thd, table_ref, table_ref_1, table_ref_2, using_fields, found_using_fields)) goto err; /* Change NATURAL JOIN to JOIN ... ON. We do this for both operands because either one of them or the other is the one with the natural join flag because RIGHT joins are transformed into LEFT, and the two tables may be reordered. */ table_ref_1->natural_join= table_ref_2->natural_join= NULL; /* Add a TRUE condition to outer joins that have no common columns. */ if (table_ref_2->outer_join && !table_ref_1->on_expr && !table_ref_2->on_expr) table_ref_2->on_expr= new Item_int((longlong) 1,1); /* Always true. */ /* Change this table reference to become a leaf for name resolution. */ if (left_neighbor) { TABLE_LIST *last_leaf_on_the_left; last_leaf_on_the_left= left_neighbor->last_leaf_for_name_resolution(); last_leaf_on_the_left->next_name_resolution_table= table_ref; } if (right_neighbor) { TABLE_LIST *first_leaf_on_the_right; first_leaf_on_the_right= right_neighbor->first_leaf_for_name_resolution(); table_ref->next_name_resolution_table= first_leaf_on_the_right; } else table_ref->next_name_resolution_table= NULL; } result= FALSE; /* All is OK. */ err: if (arena) thd->restore_active_arena(arena, &backup); DBUG_RETURN(result); } /* Compute and store the row types of the top-most NATURAL/USING joins in a FROM clause. SYNOPSIS setup_natural_join_row_types() thd current thread from_clause list of top-level table references in a FROM clause DESCRIPTION Apply the procedure 'store_top_level_join_columns' to each of the top-level table referencs of the FROM clause. Adjust the list of tables for name resolution - context->first_name_resolution_table to the top-most, lef-most NATURAL/USING join. IMPLEMENTATION Notice that the table references in 'from_clause' are in reverse order, thus when we iterate over it, we are moving from the right to the left in the FROM clause. RETURN TRUE Error FALSE OK */ static bool setup_natural_join_row_types(THD *thd, List *from_clause, Name_resolution_context *context) { thd->where= "from clause"; if (from_clause->elements == 0) return FALSE; /* We come here in the case of UNIONs. */ List_iterator_fast table_ref_it(*from_clause); TABLE_LIST *table_ref; /* Current table reference. */ /* Table reference to the left of the current. */ TABLE_LIST *left_neighbor; /* Table reference to the right of the current. */ TABLE_LIST *right_neighbor= NULL; /* Note that tables in the list are in reversed order */ for (left_neighbor= table_ref_it++; left_neighbor ; ) { table_ref= left_neighbor; left_neighbor= table_ref_it++; /* For stored procedures do not redo work if already done. */ if (context->select_lex->first_execution) { if (store_top_level_join_columns(thd, table_ref, left_neighbor, right_neighbor)) return TRUE; if (left_neighbor) { TABLE_LIST *first_leaf_on_the_right; first_leaf_on_the_right= table_ref->first_leaf_for_name_resolution(); left_neighbor->next_name_resolution_table= first_leaf_on_the_right; } } right_neighbor= table_ref; } /* Store the top-most, left-most NATURAL/USING join, so that we start the search from that one instead of context->table_list. At this point right_neighbor points to the left-most top-level table reference in the FROM clause. */ DBUG_ASSERT(right_neighbor); context->first_name_resolution_table= right_neighbor->first_leaf_for_name_resolution(); return FALSE; } /**************************************************************************** ** Expand all '*' in given fields ****************************************************************************/ int setup_wild(THD *thd, TABLE_LIST *tables, List &fields, List *sum_func_list, uint wild_num) { if (!wild_num) return(0); Item *item; List_iterator it(fields); Query_arena *arena, backup; DBUG_ENTER("setup_wild"); /* Don't use arena if we are not in prepared statements or stored procedures For PS/SP we have to use arena to remember the changes */ arena= thd->activate_stmt_arena_if_needed(&backup); thd->lex->current_select->cur_pos_in_select_list= 0; while (wild_num && (item= it++)) { if (item->type() == Item::FIELD_ITEM && ((Item_field*) item)->field_name && ((Item_field*) item)->field_name[0] == '*' && !((Item_field*) item)->field) { uint elem= fields.elements; bool any_privileges= ((Item_field *) item)->any_privileges; Item_subselect *subsel= thd->lex->current_select->master_unit()->item; if (subsel && subsel->substype() == Item_subselect::EXISTS_SUBS) { /* It is EXISTS(SELECT * ...) and we can replace * by any constant. Item_int do not need fix_fields() because it is basic constant. */ it.replace(new Item_int("Not_used", (longlong) 1, MY_INT64_NUM_DECIMAL_DIGITS)); } else if (insert_fields(thd, ((Item_field*) item)->context, ((Item_field*) item)->db_name, ((Item_field*) item)->table_name, &it, any_privileges)) { if (arena) thd->restore_active_arena(arena, &backup); DBUG_RETURN(-1); } if (sum_func_list) { /* sum_func_list is a list that has the fields list as a tail. Because of this we have to update the element count also for this list after expanding the '*' entry. */ sum_func_list->elements+= fields.elements - elem; } wild_num--; } else thd->lex->current_select->cur_pos_in_select_list++; } thd->lex->current_select->cur_pos_in_select_list= UNDEF_POS; if (arena) { /* make * substituting permanent */ SELECT_LEX *select_lex= thd->lex->current_select; select_lex->with_wild= 0; select_lex->item_list= fields; thd->restore_active_arena(arena, &backup); } DBUG_RETURN(0); } /**************************************************************************** ** Check that all given fields exists and fill struct with current data ****************************************************************************/ bool setup_fields(THD *thd, Item **ref_pointer_array, List &fields, enum_mark_columns mark_used_columns, List *sum_func_list, bool allow_sum_func) { reg2 Item *item; enum_mark_columns save_mark_used_columns= thd->mark_used_columns; nesting_map save_allow_sum_func= thd->lex->allow_sum_func; List_iterator it(fields); bool save_is_item_list_lookup; DBUG_ENTER("setup_fields"); thd->mark_used_columns= mark_used_columns; DBUG_PRINT("info", ("thd->mark_used_columns: %d", thd->mark_used_columns)); if (allow_sum_func) thd->lex->allow_sum_func|= 1 << thd->lex->current_select->nest_level; thd->where= THD::DEFAULT_WHERE; save_is_item_list_lookup= thd->lex->current_select->is_item_list_lookup; thd->lex->current_select->is_item_list_lookup= 0; /* To prevent fail on forward lookup we fill it with zerows, then if we got pointer on zero after find_item_in_list we will know that it is forward lookup. There is other way to solve problem: fill array with pointers to list, but it will be slower. TODO: remove it when (if) we made one list for allfields and ref_pointer_array */ if (ref_pointer_array) bzero(ref_pointer_array, sizeof(Item *) * fields.elements); Item **ref= ref_pointer_array; thd->lex->current_select->cur_pos_in_select_list= 0; while ((item= it++)) { if (!item->fixed && item->fix_fields(thd, it.ref()) || (item= *(it.ref()))->check_cols(1)) { thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup; thd->lex->allow_sum_func= save_allow_sum_func; thd->mark_used_columns= save_mark_used_columns; DBUG_PRINT("info", ("thd->mark_used_columns: %d", thd->mark_used_columns)); DBUG_RETURN(TRUE); /* purecov: inspected */ } if (ref) *(ref++)= item; if (item->with_sum_func && item->type() != Item::SUM_FUNC_ITEM && sum_func_list) item->split_sum_func(thd, ref_pointer_array, *sum_func_list); thd->used_tables|= item->used_tables(); thd->lex->current_select->cur_pos_in_select_list++; } thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup; thd->lex->current_select->cur_pos_in_select_list= UNDEF_POS; thd->lex->allow_sum_func= save_allow_sum_func; thd->mark_used_columns= save_mark_used_columns; DBUG_PRINT("info", ("thd->mark_used_columns: %d", thd->mark_used_columns)); DBUG_RETURN(test(thd->is_error())); } /* make list of leaves of join table tree SYNOPSIS make_leaves_list() list pointer to pointer on list first element tables table list RETURN pointer on pointer to next_leaf of last element */ TABLE_LIST **make_leaves_list(TABLE_LIST **list, TABLE_LIST *tables) { for (TABLE_LIST *table= tables; table; table= table->next_local) { if (table->merge_underlying_list) { DBUG_ASSERT(table->view && table->effective_algorithm == VIEW_ALGORITHM_MERGE); list= make_leaves_list(list, table->merge_underlying_list); } else { *list= table; list= &table->next_leaf; } } return list; } /* prepare tables SYNOPSIS setup_tables() thd Thread handler context name resolution contest to setup table list there from_clause Top-level list of table references in the FROM clause tables Table list (select_lex->table_list) leaves List of join table leaves list (select_lex->leaf_tables) refresh It is onle refresh for subquery select_insert It is SELECT ... INSERT command NOTE Check also that the 'used keys' and 'ignored keys' exists and set up the table structure accordingly. Create a list of leaf tables. For queries with NATURAL/USING JOINs, compute the row types of the top most natural/using join table references and link these into a list of table references for name resolution. This has to be called for all tables that are used by items, as otherwise table->map is not set and all Item_field will be regarded as const items. RETURN FALSE ok; In this case *map will includes the chosen index TRUE error */ bool setup_tables(THD *thd, Name_resolution_context *context, List *from_clause, TABLE_LIST *tables, TABLE_LIST **leaves, bool select_insert) { uint tablenr= 0; DBUG_ENTER("setup_tables"); DBUG_ASSERT ((select_insert && !tables->next_name_resolution_table) || !tables || (context->table_list && context->first_name_resolution_table)); /* this is used for INSERT ... SELECT. For select we setup tables except first (and its underlying tables) */ TABLE_LIST *first_select_table= (select_insert ? tables->next_local: 0); if (!(*leaves)) make_leaves_list(leaves, tables); TABLE_LIST *table_list; for (table_list= *leaves; table_list; table_list= table_list->next_leaf, tablenr++) { TABLE *table= table_list->table; table->pos_in_table_list= table_list; if (first_select_table && table_list->top_table() == first_select_table) { /* new counting for SELECT of INSERT ... SELECT command */ first_select_table= 0; tablenr= 0; } setup_table_map(table, table_list, tablenr); if (table_list->process_index_hints(table)) DBUG_RETURN(1); } if (tablenr > MAX_TABLES) { my_error(ER_TOO_MANY_TABLES,MYF(0),MAX_TABLES); DBUG_RETURN(1); } for (table_list= tables; table_list; table_list= table_list->next_local) { if (table_list->merge_underlying_list) { DBUG_ASSERT(table_list->view && table_list->effective_algorithm == VIEW_ALGORITHM_MERGE); Query_arena *arena= thd->stmt_arena, backup; bool res; if (arena->is_conventional()) arena= 0; // For easier test else thd->set_n_backup_active_arena(arena, &backup); res= table_list->setup_underlying(thd); if (arena) thd->restore_active_arena(arena, &backup); if (res) DBUG_RETURN(1); } } /* Precompute and store the row types of NATURAL/USING joins. */ if (setup_natural_join_row_types(thd, from_clause, context)) DBUG_RETURN(1); DBUG_RETURN(0); } /* prepare tables and check access for the view tables SYNOPSIS setup_tables_and_check_view_access() thd Thread handler context name resolution contest to setup table list there from_clause Top-level list of table references in the FROM clause tables Table list (select_lex->table_list) conds Condition of current SELECT (can be changed by VIEW) leaves List of join table leaves list (select_lex->leaf_tables) refresh It is onle refresh for subquery select_insert It is SELECT ... INSERT command want_access what access is needed NOTE a wrapper for check_tables that will also check the resulting table leaves list for access to all the tables that belong to a view RETURN FALSE ok; In this case *map will include the chosen index TRUE error */ bool setup_tables_and_check_access(THD *thd, Name_resolution_context *context, List *from_clause, TABLE_LIST *tables, TABLE_LIST **leaves, bool select_insert, ulong want_access_first, ulong want_access) { TABLE_LIST *leaves_tmp= NULL; bool first_table= true; if (setup_tables(thd, context, from_clause, tables, &leaves_tmp, select_insert)) return TRUE; if (leaves) *leaves= leaves_tmp; for (; leaves_tmp; leaves_tmp= leaves_tmp->next_leaf) { if (leaves_tmp->belong_to_view && check_single_table_access(thd, first_table ? want_access_first : want_access, leaves_tmp, FALSE)) { tables->hide_view_error(thd); return TRUE; } first_table= 0; } return FALSE; } /* Create a key_map from a list of index names SYNOPSIS get_key_map_from_key_list() map key_map to fill in table Table index_list List of index names RETURN 0 ok; In this case *map will includes the choosed index 1 error */ bool get_key_map_from_key_list(key_map *map, TABLE *table, List *index_list) { List_iterator_fast it(*index_list); String *name; uint pos; map->clear_all(); while ((name=it++)) { if (table->s->keynames.type_names == 0 || (pos= find_type(&table->s->keynames, name->ptr(), name->length(), 1)) <= 0) { my_error(ER_KEY_DOES_NOT_EXITS, MYF(0), name->c_ptr(), table->pos_in_table_list->alias); map->set_all(); return 1; } map->set_bit(pos-1); } return 0; } /* Drops in all fields instead of current '*' field SYNOPSIS insert_fields() thd Thread handler context Context for name resolution db_name Database name in case of 'database_name.table_name.*' table_name Table name in case of 'table_name.*' it Pointer to '*' any_privileges 0 If we should ensure that we have SELECT privileges for all columns 1 If any privilege is ok RETURN 0 ok 'it' is updated to point at last inserted 1 error. Error message is generated but not sent to client */ bool insert_fields(THD *thd, Name_resolution_context *context, const char *db_name, const char *table_name, List_iterator *it, bool any_privileges) { Field_iterator_table_ref field_iterator; bool found; char name_buff[NAME_LEN+1]; DBUG_ENTER("insert_fields"); DBUG_PRINT("arena", ("stmt arena: 0x%lx", (ulong)thd->stmt_arena)); if (db_name && lower_case_table_names) { /* convert database to lower case for comparison We can't do this in Item_field as this would change the 'name' of the item which may be used in the select list */ strmake(name_buff, db_name, sizeof(name_buff)-1); my_casedn_str(files_charset_info, name_buff); db_name= name_buff; } found= FALSE; /* If table names are qualified, then loop over all tables used in the query, else treat natural joins as leaves and do not iterate over their underlying tables. */ for (TABLE_LIST *tables= (table_name ? context->table_list : context->first_name_resolution_table); tables; tables= (table_name ? tables->next_local : tables->next_name_resolution_table) ) { Field *field; TABLE *table= tables->table; DBUG_ASSERT(tables->is_leaf_for_name_resolution()); if (table_name && my_strcasecmp(table_alias_charset, table_name, tables->alias) || (db_name && strcmp(tables->db,db_name))) continue; #ifndef NO_EMBEDDED_ACCESS_CHECKS /* Ensure that we have access rights to all fields to be inserted. */ if (!((table && (table->grant.privilege & SELECT_ACL) || tables->view && (tables->grant.privilege & SELECT_ACL))) && !any_privileges) { field_iterator.set(tables); if (check_grant_all_columns(thd, SELECT_ACL, &field_iterator)) DBUG_RETURN(TRUE); } #endif /* Update the tables used in the query based on the referenced fields. For views and natural joins this update is performed inside the loop below. */ if (table) thd->used_tables|= table->map; /* Initialize a generic field iterator for the current table reference. Notice that it is guaranteed that this iterator will iterate over the fields of a single table reference, because 'tables' is a leaf (for name resolution purposes). */ field_iterator.set(tables); for (; !field_iterator.end_of_fields(); field_iterator.next()) { Item *item; if (!(item= field_iterator.create_item(thd))) DBUG_RETURN(TRUE); if (!found) { found= TRUE; it->replace(item); /* Replace '*' with the first found item. */ } else it->after(item); /* Add 'item' to the SELECT list. */ #ifndef NO_EMBEDDED_ACCESS_CHECKS /* Set privilege information for the fields of newly created views. We have that (any_priviliges == TRUE) if and only if we are creating a view. In the time of view creation we can't use the MERGE algorithm, therefore if 'tables' is itself a view, it is represented by a temporary table. Thus in this case we can be sure that 'item' is an Item_field. */ if (any_privileges) { DBUG_ASSERT(tables->field_translation == NULL && table || tables->is_natural_join); DBUG_ASSERT(item->type() == Item::FIELD_ITEM); Item_field *fld= (Item_field*) item; const char *field_table_name= field_iterator.table_name(); if (!tables->schema_table && !(fld->have_privileges= (get_column_grant(thd, field_iterator.grant(), field_iterator.db_name(), field_table_name, fld->field_name) & VIEW_ANY_ACL))) { my_error(ER_COLUMNACCESS_DENIED_ERROR, MYF(0), "ANY", thd->security_ctx->priv_user, thd->security_ctx->host_or_ip, fld->field_name, field_table_name); DBUG_RETURN(TRUE); } } #endif if ((field= field_iterator.field())) { /* Mark fields as used to allow storage engine to optimze access */ bitmap_set_bit(field->table->read_set, field->field_index); if (table) { table->covering_keys.intersect(field->part_of_key); table->merge_keys.merge(field->part_of_key); } if (tables->is_natural_join) { TABLE *field_table; /* In this case we are sure that the column ref will not be created because it was already created and stored with the natural join. */ Natural_join_column *nj_col; if (!(nj_col= field_iterator.get_natural_column_ref())) DBUG_RETURN(TRUE); DBUG_ASSERT(nj_col->table_field); field_table= nj_col->table_ref->table; if (field_table) { thd->used_tables|= field_table->map; field_table->covering_keys.intersect(field->part_of_key); field_table->merge_keys.merge(field->part_of_key); field_table->used_fields++; } } } else thd->used_tables|= item->used_tables(); thd->lex->current_select->cur_pos_in_select_list++; } /* In case of stored tables, all fields are considered as used, while in the case of views, the fields considered as used are the ones marked in setup_tables during fix_fields of view columns. For NATURAL joins, used_tables is updated in the IF above. */ if (table) table->used_fields= table->s->fields; } if (found) DBUG_RETURN(FALSE); /* TODO: in the case when we skipped all columns because there was a qualified '*', and all columns were coalesced, we have to give a more meaningful message than ER_BAD_TABLE_ERROR. */ if (!table_name) my_message(ER_NO_TABLES_USED, ER(ER_NO_TABLES_USED), MYF(0)); else my_error(ER_BAD_TABLE_ERROR, MYF(0), table_name); DBUG_RETURN(TRUE); } /* Fix all conditions and outer join expressions. SYNOPSIS setup_conds() thd thread handler tables list of tables for name resolving (select_lex->table_list) leaves list of leaves of join table tree (select_lex->leaf_tables) conds WHERE clause DESCRIPTION TODO RETURN TRUE if some error occured (e.g. out of memory) FALSE if all is OK */ int setup_conds(THD *thd, TABLE_LIST *tables, TABLE_LIST *leaves, COND **conds) { SELECT_LEX *select_lex= thd->lex->current_select; Query_arena *arena= thd->stmt_arena, backup; TABLE_LIST *table= NULL; // For HP compilers /* it_is_update set to TRUE when tables of primary SELECT_LEX (SELECT_LEX which belong to LEX, i.e. most up SELECT) will be updated by INSERT/UPDATE/LOAD NOTE: using this condition helps to prevent call of prepare_check_option() from subquery of VIEW, because tables of subquery belongs to VIEW (see condition before prepare_check_option() call) */ bool it_is_update= (select_lex == &thd->lex->select_lex) && thd->lex->which_check_option_applicable(); bool save_is_item_list_lookup= select_lex->is_item_list_lookup; select_lex->is_item_list_lookup= 0; DBUG_ENTER("setup_conds"); if (select_lex->conds_processed_with_permanent_arena || arena->is_conventional()) arena= 0; // For easier test thd->mark_used_columns= MARK_COLUMNS_READ; DBUG_PRINT("info", ("thd->mark_used_columns: %d", thd->mark_used_columns)); select_lex->cond_count= 0; select_lex->between_count= 0; select_lex->max_equal_elems= 0; for (table= tables; table; table= table->next_local) { if (table->prepare_where(thd, conds, FALSE)) goto err_no_arena; } if (*conds) { thd->where="where clause"; if (!(*conds)->fixed && (*conds)->fix_fields(thd, conds) || (*conds)->check_cols(1)) goto err_no_arena; } /* Apply fix_fields() to all ON clauses at all levels of nesting, including the ones inside view definitions. */ for (table= leaves; table; table= table->next_leaf) { TABLE_LIST *embedded; /* The table at the current level of nesting. */ TABLE_LIST *embedding= table; /* The parent nested table reference. */ do { embedded= embedding; if (embedded->on_expr) { /* Make a join an a expression */ thd->where="on clause"; if (!embedded->on_expr->fixed && embedded->on_expr->fix_fields(thd, &embedded->on_expr) || embedded->on_expr->check_cols(1)) goto err_no_arena; select_lex->cond_count++; } embedding= embedded->embedding; } while (embedding && embedding->nested_join->join_list.head() == embedded); /* process CHECK OPTION */ if (it_is_update) { TABLE_LIST *view= table->top_table(); if (view->effective_with_check) { if (view->prepare_check_option(thd)) goto err_no_arena; thd->change_item_tree(&table->check_option, view->check_option); } } } if (!thd->stmt_arena->is_conventional()) { /* We are in prepared statement preparation code => we should store WHERE clause changing for next executions. We do this ON -> WHERE transformation only once per PS/SP statement. */ select_lex->where= *conds; select_lex->conds_processed_with_permanent_arena= 1; } thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup; DBUG_RETURN(test(thd->is_error())); err_no_arena: select_lex->is_item_list_lookup= save_is_item_list_lookup; DBUG_RETURN(1); } /****************************************************************************** ** Fill a record with data (for INSERT or UPDATE) ** Returns : 1 if some field has wrong type ******************************************************************************/ /* Fill fields with given items. SYNOPSIS fill_record() thd thread handler fields Item_fields list to be filled values values to fill with ignore_errors TRUE if we should ignore errors NOTE fill_record() may set table->auto_increment_field_not_null and a caller should make sure that it is reset after their last call to this function. RETURN FALSE OK TRUE error occured */ static bool fill_record(THD * thd, List &fields, List &values, bool ignore_errors) { List_iterator_fast f(fields),v(values); Item *value, *fld; Item_field *field; TABLE *table= 0; DBUG_ENTER("fill_record"); /* Reset the table->auto_increment_field_not_null as it is valid for only one row. */ if (fields.elements) { /* On INSERT or UPDATE fields are checked to be from the same table, thus we safely can take table from the first field. */ fld= (Item_field*)f++; if (!(field= fld->filed_for_view_update())) { my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), fld->name); goto err; } table= field->field->table; table->auto_increment_field_not_null= FALSE; f.rewind(); } while ((fld= f++)) { if (!(field= fld->filed_for_view_update())) { my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), fld->name); goto err; } value=v++; Field *rfield= field->field; table= rfield->table; if (rfield == table->next_number_field) table->auto_increment_field_not_null= TRUE; if ((value->save_in_field(rfield, 0) < 0) && !ignore_errors) { my_message(ER_UNKNOWN_ERROR, ER(ER_UNKNOWN_ERROR), MYF(0)); goto err; } } DBUG_RETURN(thd->is_error()); err: if (table) table->auto_increment_field_not_null= FALSE; DBUG_RETURN(TRUE); } /* Fill fields in list with values from the list of items and invoke before triggers. SYNOPSIS fill_record_n_invoke_before_triggers() thd thread context fields Item_fields list to be filled values values to fill with ignore_errors TRUE if we should ignore errors triggers object holding list of triggers to be invoked event event type for triggers to be invoked NOTE This function assumes that fields which values will be set and triggers to be invoked belong to the same table, and that TABLE::record[0] and record[1] buffers correspond to new and old versions of row respectively. RETURN FALSE OK TRUE error occured */ bool fill_record_n_invoke_before_triggers(THD *thd, List &fields, List &values, bool ignore_errors, Table_triggers_list *triggers, enum trg_event_type event) { return (fill_record(thd, fields, values, ignore_errors) || triggers && triggers->process_triggers(thd, event, TRG_ACTION_BEFORE, TRUE)); } /* Fill field buffer with values from Field list SYNOPSIS fill_record() thd thread handler ptr pointer on pointer to record values list of fields ignore_errors TRUE if we should ignore errors NOTE fill_record() may set table->auto_increment_field_not_null and a caller should make sure that it is reset after their last call to this function. RETURN FALSE OK TRUE error occured */ bool fill_record(THD *thd, Field **ptr, List &values, bool ignore_errors) { List_iterator_fast v(values); Item *value; TABLE *table= 0; DBUG_ENTER("fill_record"); Field *field; /* Reset the table->auto_increment_field_not_null as it is valid for only one row. */ if (*ptr) { /* On INSERT or UPDATE fields are checked to be from the same table, thus we safely can take table from the first field. */ table= (*ptr)->table; table->auto_increment_field_not_null= FALSE; } while ((field = *ptr++) && ! thd->is_error()) { value=v++; table= field->table; if (field == table->next_number_field) table->auto_increment_field_not_null= TRUE; if (value->save_in_field(field, 0) < 0) goto err; } DBUG_RETURN(thd->is_error()); err: if (table) table->auto_increment_field_not_null= FALSE; DBUG_RETURN(TRUE); } /* Fill fields in array with values from the list of items and invoke before triggers. SYNOPSIS fill_record_n_invoke_before_triggers() thd thread context ptr NULL-ended array of fields to be filled values values to fill with ignore_errors TRUE if we should ignore errors triggers object holding list of triggers to be invoked event event type for triggers to be invoked NOTE This function assumes that fields which values will be set and triggers to be invoked belong to the same table, and that TABLE::record[0] and record[1] buffers correspond to new and old versions of row respectively. RETURN FALSE OK TRUE error occured */ bool fill_record_n_invoke_before_triggers(THD *thd, Field **ptr, List &values, bool ignore_errors, Table_triggers_list *triggers, enum trg_event_type event) { return (fill_record(thd, ptr, values, ignore_errors) || triggers && triggers->process_triggers(thd, event, TRG_ACTION_BEFORE, TRUE)); } my_bool mysql_rm_tmp_tables(void) { uint i, idx; char filePath[FN_REFLEN], *tmpdir, filePathCopy[FN_REFLEN]; MY_DIR *dirp; FILEINFO *file; TABLE_SHARE share; THD *thd; DBUG_ENTER("mysql_rm_tmp_tables"); if (!(thd= new THD)) DBUG_RETURN(1); thd->thread_stack= (char*) &thd; thd->store_globals(); for (i=0; i<=mysql_tmpdir_list.max; i++) { tmpdir=mysql_tmpdir_list.list[i]; /* See if the directory exists */ if (!(dirp = my_dir(tmpdir,MYF(MY_WME | MY_DONT_SORT)))) continue; /* Remove all SQLxxx tables from directory */ for (idx=0 ; idx < (uint) dirp->number_off_files ; idx++) { file=dirp->dir_entry+idx; /* skiping . and .. */ if (file->name[0] == '.' && (!file->name[1] || (file->name[1] == '.' && !file->name[2]))) continue; if (!bcmp((uchar*) file->name, (uchar*) tmp_file_prefix, tmp_file_prefix_length)) { char *ext= fn_ext(file->name); uint ext_len= strlen(ext); uint filePath_len= my_snprintf(filePath, sizeof(filePath), "%s%c%s", tmpdir, FN_LIBCHAR, file->name); if (!bcmp((uchar*) reg_ext, (uchar*) ext, ext_len)) { handler *handler_file= 0; /* We should cut file extention before deleting of table */ memcpy(filePathCopy, filePath, filePath_len - ext_len); filePathCopy[filePath_len - ext_len]= 0; init_tmp_table_share(thd, &share, "", 0, "", filePathCopy); if (!open_table_def(thd, &share, 0) && ((handler_file= get_new_handler(&share, thd->mem_root, share.db_type())))) { handler_file->ha_delete_table(filePathCopy); delete handler_file; } free_table_share(&share); } /* File can be already deleted by tmp_table.file->delete_table(). So we hide error messages which happnes during deleting of these files(MYF(0)). */ VOID(my_delete(filePath, MYF(0))); } } my_dirend(dirp); } delete thd; my_pthread_setspecific_ptr(THR_THD, 0); DBUG_RETURN(0); } /***************************************************************************** unireg support functions *****************************************************************************/ /* Invalidate any cache entries that are for some DB SYNOPSIS remove_db_from_cache() db Database name. This will be in lower case if lower_case_table_name is set NOTE: We can't use hash_delete when looping hash_elements. We mark them first and afterwards delete those marked unused. */ void remove_db_from_cache(const char *db) { for (uint idx=0 ; idx < open_cache.records ; idx++) { TABLE *table=(TABLE*) hash_element(&open_cache,idx); if (!strcmp(table->s->db.str, db)) { table->s->version= 0L; /* Free when thread is ready */ if (!table->in_use) relink_unused(table); } } while (unused_tables && !unused_tables->s->version) VOID(hash_delete(&open_cache,(uchar*) unused_tables)); } /* free all unused tables NOTE This is called by 'handle_manager' when one wants to periodicly flush all not used tables. */ void flush_tables() { (void) pthread_mutex_lock(&LOCK_open); while (unused_tables) hash_delete(&open_cache,(uchar*) unused_tables); (void) pthread_mutex_unlock(&LOCK_open); } /* Mark all entries with the table as deleted to force an reopen of the table The table will be closed (not stored in cache) by the current thread when close_thread_tables() is called. PREREQUISITES Lock on LOCK_open() RETURN 0 This thread now have exclusive access to this table and no other thread can access the table until close_thread_tables() is called. 1 Table is in use by another thread */ bool remove_table_from_cache(THD *thd, const char *db, const char *table_name, uint flags) { char key[MAX_DBKEY_LENGTH]; uint key_length; TABLE *table; TABLE_SHARE *share; bool result= 0, signalled= 0; DBUG_ENTER("remove_table_from_cache"); DBUG_PRINT("enter", ("table: '%s'.'%s' flags: %u", db, table_name, flags)); key_length=(uint) (strmov(strmov(key,db)+1,table_name)-key)+1; for (;;) { HASH_SEARCH_STATE state; result= signalled= 0; for (table= (TABLE*) hash_first(&open_cache, (uchar*) key, key_length, &state); table; table= (TABLE*) hash_next(&open_cache, (uchar*) key, key_length, &state)) { THD *in_use; DBUG_PRINT("tcache", ("found table: '%s'.'%s' 0x%lx", table->s->db.str, table->s->table_name.str, (long) table)); table->s->version=0L; /* Free when thread is ready */ if (!(in_use=table->in_use)) { DBUG_PRINT("info",("Table was not in use")); relink_unused(table); } else if (in_use != thd) { DBUG_PRINT("info", ("Table was in use by other thread")); /* Mark that table is going to be deleted from cache. This will force threads that are in mysql_lock_tables() (but not yet in thr_multi_lock()) to abort it's locks, close all tables and retry */ in_use->some_tables_deleted= 1; if (table->is_name_opened()) { DBUG_PRINT("info", ("Found another active instance of the table")); result=1; } /* Kill delayed insert threads */ if ((in_use->system_thread & SYSTEM_THREAD_DELAYED_INSERT) && ! in_use->killed) { in_use->killed= THD::KILL_CONNECTION; pthread_mutex_lock(&in_use->mysys_var->mutex); if (in_use->mysys_var->current_cond) { pthread_mutex_lock(in_use->mysys_var->current_mutex); signalled= 1; pthread_cond_broadcast(in_use->mysys_var->current_cond); pthread_mutex_unlock(in_use->mysys_var->current_mutex); } pthread_mutex_unlock(&in_use->mysys_var->mutex); } /* Now we must abort all tables locks used by this thread as the thread may be waiting to get a lock for another table. Note that we need to hold LOCK_open while going through the list. So that the other thread cannot change it. The other thread must also hold LOCK_open whenever changing the open_tables list. Aborting the MERGE lock after a child was closed and before the parent is closed would be fatal. */ for (TABLE *thd_table= in_use->open_tables; thd_table ; thd_table= thd_table->next) { /* Do not handle locks of MERGE children. */ if (thd_table->db_stat && !thd_table->parent) // If table is open signalled|= mysql_lock_abort_for_thread(thd, thd_table); } } else { DBUG_PRINT("info", ("Table was in use by current thread. db_stat: %u", table->db_stat)); result= result || (flags & RTFC_OWNED_BY_THD_FLAG); } } while (unused_tables && !unused_tables->s->version) VOID(hash_delete(&open_cache,(uchar*) unused_tables)); DBUG_PRINT("info", ("Removing table from table_def_cache")); /* Remove table from table definition cache if it's not in use */ if ((share= (TABLE_SHARE*) hash_search(&table_def_cache,(uchar*) key, key_length))) { DBUG_PRINT("info", ("share version: %lu ref_count: %u", share->version, share->ref_count)); share->version= 0; // Mark for delete if (share->ref_count == 0) { pthread_mutex_lock(&share->mutex); VOID(hash_delete(&table_def_cache, (uchar*) share)); } } if (result && (flags & RTFC_WAIT_OTHER_THREAD_FLAG)) { /* Signal any thread waiting for tables to be freed to reopen their tables */ broadcast_refresh(); DBUG_PRINT("info", ("Waiting for refresh signal")); if (!(flags & RTFC_CHECK_KILLED_FLAG) || !thd->killed) { dropping_tables++; if (likely(signalled)) (void) pthread_cond_wait(&COND_refresh, &LOCK_open); else { struct timespec abstime; /* It can happen that another thread has opened the table but has not yet locked any table at all. Since it can be locked waiting for a table that our thread has done LOCK TABLE x WRITE on previously, we need to ensure that the thread actually hears our signal before we go to sleep. Thus we wait for a short time and then we retry another loop in the remove_table_from_cache routine. */ set_timespec(abstime, 10); pthread_cond_timedwait(&COND_refresh, &LOCK_open, &abstime); } dropping_tables--; continue; } } break; } DBUG_RETURN(result); } int setup_ftfuncs(SELECT_LEX *select_lex) { List_iterator li(*(select_lex->ftfunc_list)), lj(*(select_lex->ftfunc_list)); Item_func_match *ftf, *ftf2; while ((ftf=li++)) { if (ftf->fix_index()) return 1; lj.rewind(); while ((ftf2=lj++) != ftf) { if (ftf->eq(ftf2,1) && !ftf2->master) ftf2->master=ftf; } } return 0; } int init_ftfuncs(THD *thd, SELECT_LEX *select_lex, bool no_order) { if (select_lex->ftfunc_list->elements) { List_iterator li(*(select_lex->ftfunc_list)); Item_func_match *ifm; DBUG_PRINT("info",("Performing FULLTEXT search")); thd_proc_info(thd, "FULLTEXT initialization"); while ((ifm=li++)) ifm->init_search(no_order); } return 0; } /* open new .frm format table SYNOPSIS open_new_frm() THD thread handler path path to .frm file (without extension) alias alias for table db database table_name name of table db_stat open flags (for example ->OPEN_KEYFILE|HA_OPEN_RNDFILE..) can be 0 (example in ha_example_table) prgflag READ_ALL etc.. ha_open_flags HA_OPEN_ABORT_IF_LOCKED etc.. outparam result table table_desc TABLE_LIST descriptor mem_root temporary MEM_ROOT for parsing */ static bool open_new_frm(THD *thd, TABLE_SHARE *share, const char *alias, uint db_stat, uint prgflag, uint ha_open_flags, TABLE *outparam, TABLE_LIST *table_desc, MEM_ROOT *mem_root) { LEX_STRING pathstr; File_parser *parser; char path[FN_REFLEN]; DBUG_ENTER("open_new_frm"); /* Create path with extension */ pathstr.length= (uint) (strxmov(path, share->normalized_path.str, reg_ext, NullS)- path); pathstr.str= path; if ((parser= sql_parse_prepare(&pathstr, mem_root, 1))) { if (is_equal(&view_type, parser->type())) { if (table_desc == 0 || table_desc->required_type == FRMTYPE_TABLE) { my_error(ER_WRONG_OBJECT, MYF(0), share->db.str, share->table_name.str, "BASE TABLE"); goto err; } if (mysql_make_view(thd, parser, table_desc, (prgflag & OPEN_VIEW_NO_PARSE))) goto err; } else { /* only VIEWs are supported now */ my_error(ER_FRM_UNKNOWN_TYPE, MYF(0), share->path.str, parser->type()->str); goto err; } DBUG_RETURN(0); } err: bzero(outparam, sizeof(TABLE)); // do not run repair DBUG_RETURN(1); } bool is_equal(const LEX_STRING *a, const LEX_STRING *b) { return a->length == b->length && !strncmp(a->str, b->str, a->length); } /* SYNOPSIS abort_and_upgrade_lock() lpt Parameter passing struct All parameters passed through the ALTER_PARTITION_PARAM_TYPE object RETURN VALUE 0 DESCRIPTION Remember old lock level (for possible downgrade later on), abort all waiting threads and ensure that all keeping locks currently are completed such that we own the lock exclusively and no other interaction is ongoing. thd Thread object table Table object db Database name table_name Table name old_lock_level Old lock level */ int abort_and_upgrade_lock(ALTER_PARTITION_PARAM_TYPE *lpt) { uint flags= RTFC_WAIT_OTHER_THREAD_FLAG | RTFC_CHECK_KILLED_FLAG; DBUG_ENTER("abort_and_upgrade_locks"); lpt->old_lock_type= lpt->table->reginfo.lock_type; VOID(pthread_mutex_lock(&LOCK_open)); /* If MERGE child, forward lock handling to parent. */ mysql_lock_abort(lpt->thd, lpt->table->parent ? lpt->table->parent : lpt->table, TRUE); VOID(remove_table_from_cache(lpt->thd, lpt->db, lpt->table_name, flags)); VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_RETURN(0); } /* SYNOPSIS close_open_tables_and_downgrade() RESULT VALUES NONE DESCRIPTION We need to ensure that any thread that has managed to open the table but not yet encountered our lock on the table is also thrown out to ensure that no threads see our frm changes premature to the final version. The intermediate versions are only meant for use after a crash and later REPAIR TABLE. We also downgrade locks after the upgrade to WRITE_ONLY */ /* purecov: begin deadcode */ void close_open_tables_and_downgrade(ALTER_PARTITION_PARAM_TYPE *lpt) { VOID(pthread_mutex_lock(&LOCK_open)); remove_table_from_cache(lpt->thd, lpt->db, lpt->table_name, RTFC_WAIT_OTHER_THREAD_FLAG); VOID(pthread_mutex_unlock(&LOCK_open)); /* If MERGE child, forward lock handling to parent. */ mysql_lock_downgrade_write(lpt->thd, lpt->table->parent ? lpt->table->parent : lpt->table, lpt->old_lock_type); } /* purecov: end */ /* SYNOPSIS mysql_wait_completed_table() lpt Parameter passing struct my_table My table object All parameters passed through the ALTER_PARTITION_PARAM object RETURN VALUES TRUE Failure FALSE Success DESCRIPTION We have changed the frm file and now we want to wait for all users of the old frm to complete before proceeding to ensure that no one remains that uses the old frm definition. Start by ensuring that all users of the table will be removed from cache once they are done. Then abort all that have stumbled on locks and haven't been started yet. thd Thread object table Table object db Database name table_name Table name */ void mysql_wait_completed_table(ALTER_PARTITION_PARAM_TYPE *lpt, TABLE *my_table) { char key[MAX_DBKEY_LENGTH]; uint key_length; TABLE *table; DBUG_ENTER("mysql_wait_completed_table"); key_length=(uint) (strmov(strmov(key,lpt->db)+1,lpt->table_name)-key)+1; VOID(pthread_mutex_lock(&LOCK_open)); HASH_SEARCH_STATE state; for (table= (TABLE*) hash_first(&open_cache,(uchar*) key,key_length, &state) ; table; table= (TABLE*) hash_next(&open_cache,(uchar*) key,key_length, &state)) { THD *in_use= table->in_use; table->s->version= 0L; if (!in_use) { relink_unused(table); } else { /* Kill delayed insert threads */ if ((in_use->system_thread & SYSTEM_THREAD_DELAYED_INSERT) && ! in_use->killed) { in_use->killed= THD::KILL_CONNECTION; pthread_mutex_lock(&in_use->mysys_var->mutex); if (in_use->mysys_var->current_cond) { pthread_mutex_lock(in_use->mysys_var->current_mutex); pthread_cond_broadcast(in_use->mysys_var->current_cond); pthread_mutex_unlock(in_use->mysys_var->current_mutex); } pthread_mutex_unlock(&in_use->mysys_var->mutex); } /* Now we must abort all tables locks used by this thread as the thread may be waiting to get a lock for another table. Note that we need to hold LOCK_open while going through the list. So that the other thread cannot change it. The other thread must also hold LOCK_open whenever changing the open_tables list. Aborting the MERGE lock after a child was closed and before the parent is closed would be fatal. */ for (TABLE *thd_table= in_use->open_tables; thd_table ; thd_table= thd_table->next) { /* Do not handle locks of MERGE children. */ if (thd_table->db_stat && !thd_table->parent) // If table is open mysql_lock_abort_for_thread(lpt->thd, thd_table); } } } /* We start by removing all unused objects from the cache and marking those in use for removal after completion. Now we also need to abort all that are locked and are not progressing due to being locked by our lock. We don't upgrade our lock here. If MERGE child, forward lock handling to parent. */ mysql_lock_abort(lpt->thd, my_table->parent ? my_table->parent : my_table, FALSE); VOID(pthread_mutex_unlock(&LOCK_open)); DBUG_VOID_RETURN; } /* Tells if two (or more) tables have auto_increment columns and we want to lock those tables with a write lock. SYNOPSIS has_two_write_locked_tables_with_auto_increment tables Table list NOTES: Call this function only when you have established the list of all tables which you'll want to update (including stored functions, triggers, views inside your statement). RETURN 0 No 1 Yes */ static bool has_two_write_locked_tables_with_auto_increment(TABLE_LIST *tables) { char *first_table_name= NULL, *first_db; LINT_INIT(first_db); for (TABLE_LIST *table= tables; table; table= table->next_global) { /* we must do preliminary checks as table->table may be NULL */ if (!table->placeholder() && table->table->found_next_number_field && (table->lock_type >= TL_WRITE_ALLOW_WRITE)) { if (first_table_name == NULL) { first_table_name= table->table_name; first_db= table->db; DBUG_ASSERT(first_db); } else if (strcmp(first_db, table->db) || strcmp(first_table_name, table->table_name)) return 1; } } return 0; } /* Open and lock system tables for read. SYNOPSIS open_system_tables_for_read() thd Thread context. table_list List of tables to open. backup Pointer to Open_tables_state instance where information about currently open tables will be saved, and from which will be restored when we will end work with system tables. NOTES Thanks to restrictions which we put on opening and locking of system tables for writing, we can open and lock them for reading even when we already have some other tables open and locked. One must call close_system_tables() to close systems tables opened with this call. RETURN FALSE Success TRUE Error */ bool open_system_tables_for_read(THD *thd, TABLE_LIST *table_list, Open_tables_state *backup) { DBUG_ENTER("open_system_tables_for_read"); thd->reset_n_backup_open_tables_state(backup); uint count= 0; bool not_used; for (TABLE_LIST *tables= table_list; tables; tables= tables->next_global) { TABLE *table= open_table(thd, tables, thd->mem_root, ¬_used, MYSQL_LOCK_IGNORE_FLUSH); if (!table) goto error; DBUG_ASSERT(table->s->table_category == TABLE_CATEGORY_SYSTEM); table->use_all_columns(); table->reginfo.lock_type= tables->lock_type; tables->table= table; count++; } { TABLE **list= (TABLE**) thd->alloc(sizeof(TABLE*) * count); TABLE **ptr= list; for (TABLE_LIST *tables= table_list; tables; tables= tables->next_global) *(ptr++)= tables->table; thd->lock= mysql_lock_tables(thd, list, count, MYSQL_LOCK_IGNORE_FLUSH, ¬_used); } if (thd->lock) DBUG_RETURN(FALSE); error: close_system_tables(thd, backup); DBUG_RETURN(TRUE); } /* Close system tables, opened with open_system_tables_for_read(). SYNOPSIS close_system_tables() thd Thread context backup Pointer to Open_tables_state instance which holds information about tables which were open before we decided to access system tables. */ void close_system_tables(THD *thd, Open_tables_state *backup) { close_thread_tables(thd); thd->restore_backup_open_tables_state(backup); } /* Open and lock one system table for update. SYNOPSIS open_system_table_for_update() thd Thread context. one_table Table to open. NOTES Table opened with this call should closed using close_thread_tables(). RETURN 0 Error # Pointer to TABLE object of system table */ TABLE * open_system_table_for_update(THD *thd, TABLE_LIST *one_table) { DBUG_ENTER("open_system_table_for_update"); TABLE *table= open_ltable(thd, one_table, one_table->lock_type, 0); if (table) { DBUG_ASSERT(table->s->table_category == TABLE_CATEGORY_SYSTEM); table->use_all_columns(); } DBUG_RETURN(table); } /** Open a performance schema table. Opening such tables is performed internally in the server implementation, and is a 'nested' open, since some tables might be already opened by the current thread. The thread context before this call is saved, and is restored when calling close_performance_schema_table(). @param thd The current thread @param one_table Performance schema table to open @param backup [out] Temporary storage used to save the thread context */ TABLE * open_performance_schema_table(THD *thd, TABLE_LIST *one_table, Open_tables_state *backup) { uint flags= ( MYSQL_LOCK_IGNORE_GLOBAL_READ_LOCK | MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY | MYSQL_LOCK_IGNORE_FLUSH | MYSQL_LOCK_PERF_SCHEMA); TABLE *table; /* Save value that is changed in mysql_lock_tables() */ ulonglong save_utime_after_lock= thd->utime_after_lock; DBUG_ENTER("open_performance_schema_table"); thd->reset_n_backup_open_tables_state(backup); if ((table= open_ltable(thd, one_table, one_table->lock_type, flags))) { DBUG_ASSERT(table->s->table_category == TABLE_CATEGORY_PERFORMANCE); /* Make sure all columns get assigned to a default value */ table->use_all_columns(); table->no_replicate= 1; /* Don't set automatic timestamps as we may want to use time of logging, not from query start */ table->timestamp_field_type= TIMESTAMP_NO_AUTO_SET; } else { /* If error in mysql_lock_tables(), open_ltable doesn't close the table. Thread kill during mysql_lock_tables() is such error. But open tables cannot be accepted when restoring the open tables state. */ if (thd->killed) close_thread_tables(thd); thd->restore_backup_open_tables_state(backup); } thd->utime_after_lock= save_utime_after_lock; DBUG_RETURN(table); } /** Close a performance schema table. The last table opened by open_performance_schema_table() is closed, then the thread context is restored. @param thd The current thread @param backup [in] the context to restore. */ void close_performance_schema_table(THD *thd, Open_tables_state *backup) { bool found_old_table; /* If open_performance_schema_table() fails, this function should not be called. */ DBUG_ASSERT(thd->lock != NULL); /* Note: We do not create explicitly a separate transaction for the performance table I/O, but borrow the current transaction. lock + unlock will autocommit the change done in the performance schema table: this is the expected result. The current transaction should not be affected by this code. TODO: Note that if a transactional engine is used for log tables, this code will need to be revised, as a separate transaction might be needed. */ mysql_unlock_tables(thd, thd->lock); thd->lock= 0; pthread_mutex_lock(&LOCK_open); found_old_table= false; /* Note that we need to hold LOCK_open while changing the open_tables list. Another thread may work on it. (See: remove_table_from_cache(), mysql_wait_completed_table()) Closing a MERGE child before the parent would be fatal if the other thread tries to abort the MERGE lock in between. */ while (thd->open_tables) found_old_table|= close_thread_table(thd, &thd->open_tables); if (found_old_table) broadcast_refresh(); pthread_mutex_unlock(&LOCK_open); thd->restore_backup_open_tables_state(backup); } /** @} (end of group Data_Dictionary) */