row0mysql.c:

  Manually merge the latest FOREIGN KEY lock wait + DROP TABLE fix from 4.0

innobase/row/row0mysql.c

@@ -1843,16 +1843,9 @@ row_drop_table_for_mysql_in_background(
 	ut_print_name(stderr, name);
 	fputs(" in background drop list\n", stderr); */
 
-  	/* Drop the table in InnoDB */
+  	/* Try to drop the table in InnoDB */
 
   	error = row_drop_table_for_mysql(name, trx, FALSE);
-
-	if (error != DB_SUCCESS) {
-		ut_print_timestamp(stderr);
-		fputs("  InnoDB: Error: Dropping table ", stderr);
-		ut_print_name(stderr, trx, name);
-		fputs(" in background drop list failed\n", stderr);
-	}
   	
 	/* Flush the log to reduce probability that the .frm files and
 	the InnoDB data dictionary get out-of-sync if the user runs
@@ -1864,7 +1857,7 @@ row_drop_table_for_mysql_in_background(
 
   	trx_free_for_background(trx);
 
-	return(DB_SUCCESS);
+	return(error);
 }
 
 /*************************************************************************
@@ -1898,6 +1891,7 @@ loop:
 	mutex_exit(&kernel_mutex);
 
 	if (drop == NULL) {
+		/* All tables dropped */
 
 		return(n_tables + n_tables_dropped);
 	}
@@ -1965,21 +1959,21 @@ row_get_background_drop_list_len_low(void)
 }
 
 /*************************************************************************
-Adds a table to the list of tables which the master thread drops in
-background. We need this on Unix because in ALTER TABLE MySQL may call
-drop table even if the table has running queries on it. */
+If a table is not yet in the drop list, adds the table to the list of tables
+which the master thread drops in background. We need this on Unix because in
+ALTER TABLE MySQL may call drop table even if the table has running queries on
+it. Also, if there are running foreign key checks on the table, we drop the
+table lazily. */
 static
-void
+ibool
 row_add_table_to_background_drop_list(
 /*==================================*/
+				/* out: TRUE if the table was not yet in the
+				drop list, and was added there */
 	dict_table_t*	table)	/* in: table */
 {
 	row_mysql_drop_t*	drop;
 	
-	drop = mem_alloc(sizeof(row_mysql_drop_t));
-
-	drop->table_name = mem_strdup(table->name);
-
 	mutex_enter(&kernel_mutex);
 
 	if (!row_mysql_drop_list_inited) {
@@ -1987,7 +1981,26 @@ row_add_table_to_background_drop_list(
 		UT_LIST_INIT(row_mysql_drop_list);
 		row_mysql_drop_list_inited = TRUE;
 	}
+	
+	/* Look if the table already is in the drop list */
+	drop = UT_LIST_GET_FIRST(row_mysql_drop_list);
 
+	while (drop != NULL) {
+		if (strcmp(drop->table_name, table->name) == 0) {
+			/* Already in the list */
+			
+			mutex_exit(&kernel_mutex);
+
+			return(FALSE);
+		}
+
+		drop = UT_LIST_GET_NEXT(row_mysql_drop_list, drop);
+	}
+
+	drop = mem_alloc(sizeof(row_mysql_drop_t));
+
+	drop->table_name = mem_strdup(table->name);
+ 
 	UT_LIST_ADD_LAST(row_mysql_drop_list, row_mysql_drop_list, drop);
 	
 /*	fputs("InnoDB: Adding table ", stderr);
@@ -1995,6 +2008,8 @@ row_add_table_to_background_drop_list(
 	fputs(" to background drop list\n", stderr); */
 
 	mutex_exit(&kernel_mutex);
+
+	return(TRUE);
 }
 
 /*************************************************************************
@@ -2347,7 +2362,7 @@ funct_exit:
 }
 
 /*************************************************************************
-Drops a table for MySQL.  If the name of the table to be dropped is equal
+Drops a table for MySQL. If the name of the table to be dropped is equal
 with one of the predefined magic table names, then this also stops printing
 the corresponding monitor output by the master thread. */
 
@@ -2581,19 +2596,27 @@ row_drop_table_for_mysql(
 	}
 
 	if (table->n_mysql_handles_opened > 0) {
+		ibool	added;
 
-	        ut_print_timestamp(stderr);
-		fputs("	 InnoDB: Warning: MySQL is trying to drop table ",
-			stderr);
-		ut_print_name(stderr, trx, table->name);
-		fputs("\n"
-		  "InnoDB: though there are still open handles to it.\n"
-		  "InnoDB: Adding the table to the background drop queue.\n",
-			stderr);
+		added = row_add_table_to_background_drop_list(table);
 
-		row_add_table_to_background_drop_list(table);
+	        if (added) {
+			ut_print_timestamp(stderr);
+fputs("	 InnoDB: Warning: MySQL is trying to drop table ", stderr);
+			ut_print_name(stderr, trx, table->name);
+			fputs("\n"
+"InnoDB: though there are still open handles to it.\n"
+"InnoDB: Adding the table to the background drop queue.\n",
+			stderr);
+			
+			/* We return DB_SUCCESS to MySQL though the drop will
+			happen lazily later */
 
-		err = DB_SUCCESS;
+			err = DB_SUCCESS;
+		} else {
+			/* The table is already in the background drop list */
+			err = DB_ERROR;
+		}
 
 		goto funct_exit;
 	}
@@ -2606,17 +2629,27 @@ row_drop_table_for_mysql(
 
 	if (table->n_foreign_key_checks_running > 0) {
 
-	        ut_print_timestamp(stderr);
-		fputs("	 InnoDB: You are trying to drop table ", stderr);
-		ut_print_name(stderr, trx, table->name);
-		fputs("\n"
-		 "InnoDB: though there is a foreign key check running on it.\n"
-		 "InnoDB: Adding the table to the background drop queue.\n",
+		ibool	added;
+
+		added = row_add_table_to_background_drop_list(table);
+
+		if (added) {
+	        	ut_print_timestamp(stderr);
+fputs("	 InnoDB: You are trying to drop table ", stderr);
+			ut_print_name(stderr, trx, table->name);
+			fputs("\n"
+"InnoDB: though there is a foreign key check running on it.\n"
+"InnoDB: Adding the table to the background drop queue.\n",
 			stderr);
 
-		row_add_table_to_background_drop_list(table);
+			/* We return DB_SUCCESS to MySQL though the drop will
+			happen lazily later */
 
-		err = DB_SUCCESS;
+			err = DB_SUCCESS;
+		} else {
+			/* The table is already in the background drop list */
+			err = DB_ERROR;
+		}
 
 		goto funct_exit;
 	}