diff options
Diffstat (limited to 'sql/sql_show.cc')
| -rw-r--r-- | sql/sql_show.cc | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/sql/sql_show.cc b/sql/sql_show.cc index c87538681a2..74e13caabab 100644 --- a/sql/sql_show.cc +++ b/sql/sql_show.cc @@ -2003,6 +2003,166 @@ void mysqld_list_processes(THD *thd,const char *user, bool verbose) DBUG_VOID_RETURN; } + +/* + Produce EXPLAIN data. + + This function is APC-scheduled to be run in the context of the thread that + we're producing EXPLAIN for. +*/ + +void Show_explain_request::call_in_target_thread() +{ + Query_arena backup_arena; + bool printed_anything= FALSE; + + /* + Change the arena because JOIN::print_explain and co. are going to allocate + items. Let them allocate them on our arena. + */ + target_thd->set_n_backup_active_arena((Query_arena*)request_thd, + &backup_arena); + + query_str.copy(target_thd->query(), + target_thd->query_length(), + target_thd->query_charset()); + + if (target_thd->lex->unit.print_explain(explain_buf, 0 /* explain flags*/, + &printed_anything)) + { + failed_to_produce= TRUE; + } + + if (!printed_anything) + failed_to_produce= TRUE; + + target_thd->restore_active_arena((Query_arena*)request_thd, &backup_arena); +} + + +int select_result_explain_buffer::send_data(List<Item> &items) +{ + fill_record(thd, dst_table->field, items, TRUE, FALSE); + if ((dst_table->file->ha_write_tmp_row(dst_table->record[0]))) + return 1; + return 0; +} + + +/* + Store the SHOW EXPLAIN output in the temporary table. +*/ + +int fill_show_explain(THD *thd, TABLE_LIST *table, COND *cond) +{ + const char *calling_user; + THD *tmp; + my_thread_id thread_id; + DBUG_ENTER("fill_show_explain"); + + DBUG_ASSERT(cond==NULL); + thread_id= thd->lex->value_list.head()->val_int(); + calling_user= (thd->security_ctx->master_access & PROCESS_ACL) ? NullS : + thd->security_ctx->priv_user; + + if ((tmp= find_thread_by_id(thread_id))) + { + Security_context *tmp_sctx= tmp->security_ctx; + /* + If calling_user==NULL, calling thread has SUPER or PROCESS + privilege, and so can do SHOW EXPLAIN on any user. + + if calling_user!=NULL, he's only allowed to view SHOW EXPLAIN on + his own threads. + */ + if (calling_user && (!tmp_sctx->user || strcmp(calling_user, + tmp_sctx->user))) + { + my_error(ER_SPECIFIC_ACCESS_DENIED_ERROR, MYF(0), "PROCESS"); + mysql_mutex_unlock(&tmp->LOCK_thd_data); + DBUG_RETURN(1); + } + + if (tmp == thd) + { + mysql_mutex_unlock(&tmp->LOCK_thd_data); + my_error(ER_TARGET_NOT_EXPLAINABLE, MYF(0)); + DBUG_RETURN(1); + } + + bool bres; + /* + Ok we've found the thread of interest and it won't go away because + we're holding its LOCK_thd data. Post it a SHOW EXPLAIN request. + */ + bool timed_out; + int timeout_sec= 30; + Show_explain_request explain_req; + select_result_explain_buffer *explain_buf; + + explain_buf= new select_result_explain_buffer(thd, table->table); + + explain_req.explain_buf= explain_buf; + explain_req.target_thd= tmp; + explain_req.request_thd= thd; + explain_req.failed_to_produce= FALSE; + + /* Ok, we have a lock on target->LOCK_thd_data, can call: */ + bres= tmp->apc_target.make_apc_call(thd, &explain_req, timeout_sec, &timed_out); + + if (bres || explain_req.failed_to_produce) + { + if (thd->killed) + thd->send_kill_message(); + else if (timed_out) + my_error(ER_LOCK_WAIT_TIMEOUT, MYF(0)); + else + my_error(ER_TARGET_NOT_EXPLAINABLE, MYF(0)); + + bres= TRUE; + } + else + { + /* + Push the query string as a warning. The query may be in a different + charset than the charset that's used for error messages, so, convert it + if needed. + */ + CHARSET_INFO *fromcs= explain_req.query_str.charset(); + CHARSET_INFO *tocs= error_message_charset_info; + char *warning_text; + if (!my_charset_same(fromcs, tocs)) + { + uint conv_length= 1 + tocs->mbmaxlen * explain_req.query_str.length() / + fromcs->mbminlen; + uint dummy_errors; + char *to, *p; + if (!(to= (char*)thd->alloc(conv_length + 1))) + DBUG_RETURN(1); + p= to; + p+= copy_and_convert(to, conv_length, tocs, + explain_req.query_str.c_ptr(), + explain_req.query_str.length(), fromcs, + &dummy_errors); + *p= 0; + warning_text= to; + } + else + warning_text= explain_req.query_str.c_ptr_safe(); + + push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE, + ER_YES, warning_text); + } + DBUG_RETURN(bres); + } + else + { + my_error(ER_NO_SUCH_THREAD, MYF(0), thread_id); + DBUG_RETURN(1); + } +} + + int fill_schema_processlist(THD* thd, TABLE_LIST* tables, COND* cond) { TABLE *table= tables->table; @@ -8333,6 +8493,32 @@ ST_FIELD_INFO keycache_fields_info[]= }; +ST_FIELD_INFO show_explain_fields_info[]= +{ + /* field_name, length, type, value, field_flags, old_name*/ + {"id", 3, MYSQL_TYPE_LONGLONG, 0 /*value*/, MY_I_S_MAYBE_NULL, "id", + SKIP_OPEN_TABLE}, + {"select_type", 19, MYSQL_TYPE_STRING, 0 /*value*/, 0, "select_type", + SKIP_OPEN_TABLE}, + {"table", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0 /*value*/, MY_I_S_MAYBE_NULL, + "table", SKIP_OPEN_TABLE}, + {"type", 15, MYSQL_TYPE_STRING, 0, MY_I_S_MAYBE_NULL, "type", SKIP_OPEN_TABLE}, + {"possible_keys", NAME_CHAR_LEN*MAX_KEY, MYSQL_TYPE_STRING, 0/*value*/, + MY_I_S_MAYBE_NULL, "possible_keys", SKIP_OPEN_TABLE}, + {"key", NAME_CHAR_LEN*MAX_KEY, MYSQL_TYPE_STRING, 0/*value*/, + MY_I_S_MAYBE_NULL, "key", SKIP_OPEN_TABLE}, + {"key_len", NAME_CHAR_LEN*MAX_KEY, MYSQL_TYPE_STRING, 0/*value*/, + MY_I_S_MAYBE_NULL, "key_len", SKIP_OPEN_TABLE}, + {"ref", NAME_CHAR_LEN*MAX_REF_PARTS, MYSQL_TYPE_STRING, 0/*value*/, + MY_I_S_MAYBE_NULL, "ref", SKIP_OPEN_TABLE}, + {"rows", 10, MYSQL_TYPE_LONGLONG, 0/*value*/, MY_I_S_MAYBE_NULL, "rows", + SKIP_OPEN_TABLE}, + {"Extra", 255, MYSQL_TYPE_STRING, 0/*value*/, 0 /*flags*/, "Extra", + SKIP_OPEN_TABLE}, + {0, 0, MYSQL_TYPE_STRING, 0, 0, 0, SKIP_OPEN_TABLE} +}; + + /* Description of ST_FIELD_INFO in table.h @@ -8364,6 +8550,8 @@ ST_SCHEMA_TABLE schema_tables[]= {"EVENTS", events_fields_info, create_schema_table, 0, make_old_format, 0, -1, -1, 0, 0}, #endif + {"EXPLAIN", show_explain_fields_info, create_schema_table, fill_show_explain, + make_old_format, 0, -1, -1, TRUE /*hidden*/ , 0}, {"FILES", files_fields_info, create_schema_table, hton_fill_schema_table, 0, 0, -1, -1, 0, 0}, {"GLOBAL_STATUS", variables_fields_info, create_schema_table, |