From bc7af1757939f1ec3c389da73176c7c68a8bafd5 Mon Sep 17 00:00:00 2001 From: Dmitry Shulga Date: Thu, 23 Jun 2011 20:41:04 +0700 Subject: Fixed Bug#11756013 (formerly known as bug#47870): BOGUS "THE TABLE MYSQL.PROC IS MISSING,..." There was a race condition between loading a stored routine (function/procedure/trigger) specified by fully qualified name SCHEMA_NAME.PROC_NAME and dropping the stored routine database. The problem was that there is a window for race condition when one server thread tries to load a stored routine being executed and the other thread tries to drop the stored routine schema. This condition race window exists in implementation of function mysql_change_db() called by db_load_routine() during loading of stored routine to cache. Function mysql_change_db() calls check_db_dir_existence() that might failed because specified database was dropped during concurrent execution of DROP SCHEMA statement. db_load_routine() calls mysql_change_db() with flag 'force_switch' set to 'true' value so when referenced db is not found then my_error() is not called and function mysql_change_db() returns ok. This shadows information about schema opening error in db_load_routine(). Then db_load_routine() makes attempt to parse stored routine that is failed. This makes to return error to sp_cache_routines_and_add_tables_aux() but since during error generation a call to my_error wasn't made and hence THD::main_da wasn't set we set the generic "mysql.proc table corrupt" error when running sp_cache_routines_and_add_tables_aux(). The fix is to install an error handler inside db_load_routine() for the mysql_op_change_db() call, and check later if the ER_BAD_DB_ERROR was caught. sql/sql_db.cc: Added synchronization point "before_db_dir_check" to emulate a race condition during processing of CALL/DROP SCHEMA. --- mysql-test/r/sp_sync.result | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'mysql-test/r/sp_sync.result') diff --git a/mysql-test/r/sp_sync.result b/mysql-test/r/sp_sync.result index afa37e70531..17292f4c1a8 100644 --- a/mysql-test/r/sp_sync.result +++ b/mysql-test/r/sp_sync.result @@ -1,4 +1,4 @@ -Tests of syncronization of stored procedure execution. +Tests of synchronization of stored procedure execution. # # Bug#48157: crash in Item_field::used_tables # @@ -20,4 +20,16 @@ SET DEBUG_SYNC = 'now SIGNAL go'; # code, this test statement will hang. DROP TABLE t1, t2; DROP PROCEDURE p1; +# +# test for bug#11756013 +# +DROP SCHEMA IF EXISTS s1; +CREATE SCHEMA s1; +CREATE PROCEDURE s1.p1() BEGIN END; +SET DEBUG_SYNC='before_db_dir_check SIGNAL check_db WAIT_FOR dropped_schema'; +CALL s1.p1; +SET DEBUG_SYNC='now WAIT_FOR check_db'; +DROP SCHEMA s1; +SET DEBUG_SYNC='now SIGNAL dropped_schema'; +ERROR 42000: Unknown database 's1' SET DEBUG_SYNC = 'RESET'; -- cgit v1.2.1