WL1424 Multiple MySQL Servers: SHOW TABLES etc. should detect new and delete old tables.

include/my_base.h:
  Added new bit to table create options
  Removed old error code HA_ERR_OLD_METADAT and reused it for HA_ERR_NO_SUCH_TABLE.
mysql-test/r/ndb_autodiscover.result:
  Updated test cases
mysql-test/t/ndb_autodiscover.test:
  Updated test cases
mysql-test/t/ndb_autodiscover2.test:
  Updated test cases
sql/discover.cc:
  Moved function create_table_from_handler to handler.cc
sql/ha_ndbcluster.cc:
  Improved discover functionality
  Added .ndb file
  Changed error code mappings for a table that does not exist in engine
  Check for ndb object in THD
  Updated ndbcluster_discover, ndbcluster_list_tables and ndbcluster_can_discover
sql/ha_ndbcluster.h:
  Improved discover
sql/handler.cc:
  Added new error message mapping.
  Moved function ha_create_table_from_engine to handler level
  Added new functions ha_can_discover, ha_list_tables and ha_table_exists
sql/handler.h:
  Added new error message mapping.
  Moved function ha_create_table_from_engine to handler level
  Added new functions ha_can_discover, ha_list_tables and ha_table_exists
sql/mysql_priv.h:
  Removed create_table_from_handler, moved to handler.h
sql/sql_base.cc:
  Renamed function create_table_from_handler
sql/sql_show.cc:
  Added new function mysql_discover_files and mysql_list_files. 
  Modified mysql_find_files to discover new and delete "old" files/tables.
sql/sql_table.cc:
  Renamed create_table_from_handler
  Call ha_create_table_from_engine, in order to discover the the frm file before it can be dropped.
sql/table.cc:
  Added mapping of the error code HA_ERR_NO_SUCH_TABLE

1 files changed, 173 insertions, 16 deletions

diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 57c5f01d0bf..42c48ab8d21 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -358,30 +358,59 @@ int mysqld_show_column_types(THD *thd)
 }
 
 
+
+/*
+   Ask all engines if they can provide a list of available tables.
+   Returns a list of available tables.
+*/
+
+int 
+mysql_discover_tables(THD *thd, HASH *ha_tables, const char *db, bool dir)
+{
+  DBUG_ENTER("mysql_discover_files");
+  
+  if (dir)    
+    DBUG_RETURN(0); // Discover of directories(databases) not supported yet
+  
+  // Get list of files in storage engine
+  if (ha_list_tables(thd, ha_tables, db))
+    DBUG_RETURN(-1);
+
+  DBUG_PRINT("info",("discovered: %d files", ha_tables->records));
+  DBUG_RETURN(0);
+}
+
+
+/*
+  List all files or directories in a given location
+  Returns
+   files - list of files where wild card has been applied
+   all_files - list of all files
+   dsc_files - list of files which are discoverable
+*/
+
 int
-mysql_find_files(THD *thd,List<char> *files, const char *db,const char *path,
-                 const char *wild, bool dir)
+mysql_list_files(THD *thd, const char *db, const char *path, const char *wild, 
+		 bool dir, List<char> *files, HASH *all_files, HASH* dsc_files)
 {
   uint i;
-  char *ext;
+  char *ext, **dsc_ext;
   MY_DIR *dirp;
   FILEINFO *file;
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   uint col_access=thd->col_access;
 #endif
   TABLE_LIST table_list;
-  DBUG_ENTER("mysql_find_files");
+  DBUG_ENTER("mysql_list_files");
 
-  if (wild && !wild[0])
-    wild=0;
   bzero((char*) &table_list,sizeof(table_list));
-
+  
   if (!(dirp = my_dir(path,MYF(MY_WME | (dir ? MY_WANT_STAT : 0)))))
     DBUG_RETURN(-1);
 
-  for (i=0 ; i < (uint) dirp->number_off_files  ; i++)
+  for (i= 0; i < (uint)dirp->number_off_files; i++)
   {
-    file=dirp->dir_entry+i;
+    file= dirp->dir_entry+i;
     if (dir)
     {                                           /* Return databases */
 #ifdef USE_SYMDIR
@@ -391,7 +420,7 @@ mysql_find_files(THD *thd,List<char> *files, const char *db,const char *path,
 	/* Only show the sym file if it points to a directory */
 	char buff[FN_REFLEN], *end;
 	MY_STAT status;
-        *ext=0;                                 /* Remove extension */
+        *ext= 0;                                 /* Remove extension */
 	unpack_dirname(buff, file->name);
 	end= strend(buff);
 	if (end != buff && end[-1] == FN_LIBCHAR)
@@ -410,11 +439,36 @@ mysql_find_files(THD *thd,List<char> *files, const char *db,const char *path,
     }
     else
     {
-        // Return only .frm files which aren't temp files.
-      if (my_strcasecmp(system_charset_info, ext=fn_ext(file->name),reg_ext) ||
-          is_prefix(file->name,tmp_file_prefix))
-        continue;
-      *ext=0;
+      // Don't process temp files
+      if (is_prefix(file->name, tmp_file_prefix))
+	continue;
+
+      ext= fn_ext(file->name);
+      // Check for  files that indicates the table can be discovered
+      if (ha_can_discover(thd, file->name))
+      {
+	DBUG_PRINT("info", ("Discoverable file found: %s", file->name));
+	*ext= 0;
+	if (my_hash_insert(dsc_files, (byte*)thd->strdup(file->name)))
+	{
+	  my_dirend(dirp);
+	  DBUG_RETURN(-1);
+	}
+	continue;
+      }
+
+      // Return only .frm files
+      if (my_strcasecmp(system_charset_info, ext,reg_ext))
+	continue;
+      *ext=0;	  
+
+      // Insert into list of all .frm files
+      if (my_hash_insert(all_files, (byte*)thd->strdup(file->name)))
+      {
+	my_dirend(dirp);
+	DBUG_RETURN(-1);
+      }
+
       if (wild)
       {
 	if (lower_case_table_names)
@@ -443,11 +497,114 @@ mysql_find_files(THD *thd,List<char> *files, const char *db,const char *path,
       DBUG_RETURN(-1);
     }
   }
-  DBUG_PRINT("info",("found: %d files", files->elements));
   my_dirend(dirp);
   DBUG_RETURN(0);
 }
 
+extern "C" byte* ha_tables_get_key(const char *entry, uint *length,
+				   my_bool not_used __attribute__((unused)))
+{
+  *length= strlen(entry);
+  return (byte*) entry;
+}
+
+
+int
+mysql_find_files(THD *thd,List<char> *files, const char *db,
+		 const char *path, const char *wild, bool dir)
+{
+  int error= -1;
+  uint i;
+  bool discovery_performed= false;
+  DBUG_ENTER("mysql_find_files");
+  DBUG_PRINT("enter", ("db: %s, path: %s, wild: %s, dir: %d", 
+	     db, path, wild, dir));
+
+  if (wild && !wild[0])
+    wild=0;
+
+  HASH ha_tables, all_files, dsc_files;
+  if (hash_init(&ha_tables,system_charset_info,32,0,0,
+		(hash_get_key) ha_tables_get_key,0,0) || 
+      hash_init(&all_files,system_charset_info,32,0,0,
+		(hash_get_key) ha_tables_get_key,0,0) ||
+      hash_init(&dsc_files,system_charset_info,32,0,0,
+		(hash_get_key) ha_tables_get_key,0,0))
+    goto err_end;
+    
+  if (mysql_discover_tables(thd, &ha_tables, db, dir))
+    goto err_end;
+
+  if (mysql_list_files(thd, db, path, wild, dir,
+		       files, &all_files, &dsc_files))
+    goto err_end;
+
+  /*
+    Discovery part 1
+    Loop through handler files and see if any of them should be discovered
+  */
+  for (i= 0; i < ha_tables.records; i++)
+  {
+    const char *name = hash_element(&ha_tables, i);
+    if (hash_search(&all_files, name, strlen(name)))
+      continue;
+    
+    // Table was in handler, but not in list of all tables
+    DBUG_PRINT("info", ("Table to discover[%d]: %s", i, name));
+    pthread_mutex_lock(&LOCK_open);
+    ha_create_table_from_engine(thd, db, name, true);
+    pthread_mutex_unlock(&LOCK_open);      
+    discovery_performed= true;
+  }
+
+  /*
+    Discovery part2
+    Loop through dsc files and see if any of them need to be deleted
+  */
+  for (i= 0; i < dsc_files.records; i++)
+  {
+    const char *name = hash_element(&dsc_files, i);
+    if (hash_search(&ha_tables, name, strlen(name)))
+      continue;
+
+    //  Table was only on disk and not in handler
+    DBUG_PRINT("info", ("Table[%d]: %s only exists on disk", i, name));
+
+    // Verify that handler agrees table is gone.
+    if (ha_table_exists(thd, db, name) == 0)
+    {
+      // Delete the table and all related files
+      TABLE_LIST table_list;
+      bzero((char*) &table_list,sizeof(table_list));
+      table_list.db= (char*) db;
+      table_list.real_name=(char*)name;
+      (void)mysql_rm_table_part2_with_lock(thd, &table_list, 
+					   /* if_exists */ true, 
+					   /* drop_temporary */ false, 
+					   /* dont_log_query*/ true);
+      discovery_performed= true;
+    }
+  }
+  
+  if (discovery_performed)
+  {
+    // Call mysql_list_files one more time to get an updated list    
+    DBUG_PRINT("info", ("Calling mysql_list_files one more time"));
+    files->empty();
+    if (mysql_list_files(thd, db, path, wild, dir,
+			 files, &all_files, &dsc_files))
+      goto err_end;    
+  }
+
+  DBUG_PRINT("info",("found: %d files", files->elements));
+  error = 0;
+err_end:
+  hash_free(&ha_tables);
+  hash_free(&all_files);
+  hash_free(&dsc_files);
+  DBUG_RETURN(error);
+}
+
 
 /***************************************************************************
  Extended version of mysqld_show_tables