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BUG#21142859: FUNCTION UPDATING A VIEW FAILS TO FIND TABLE

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THAT ACTUALLY EXISTS

ANALYSIS:
=========
Stored functions updating a view where the view table has a
trigger defined that updates another table, fails reporting
an error that the table doesn't exist.

If there is a trigger defined on a table, a variable
'trg_event_map' will be set to a non-zero value after the
parsed tree creation. This indicates what triggers we need to
pre-load for the TABLE_LIST when opening an associated table.

During the prelocking phase, the variable 'trg_event_map'
will not be set for the view table. This value will be set
after the processing of triggers defined on the table. During
the processing of sub-statements, 'locked_tables_mode' will be
set to 'LTM_PRELOCKED' which denotes that further locking
of tables/functions cannot be done. This results in the other
table not being locked and thus further processing results in
an error getting reported.

FIX:
====
During the prelocking of view, the value of 'trg_event_map'
of the view is copied to 'trg_event_map' of the next table
in the TABLE_LIST. This results in the locking of tables
associated with the trigger as well.
This commit is contained in:
Karthik Kamath 2016-05-18 11:07:29 +05:30
parent cb29741568
commit 90b9c957ba
3 changed files with 56 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
mysql-test/r/sp-prelocking.result
View File

@ -320,3 +320,23 @@ c2
DROP TRIGGER t1_ai;
DROP TABLE t1, t2;
End of 5.0 tests
#
# Bug#21142859: FUNCTION UPDATING A VIEW FAILS TO FIND TABLE THAT ACTUALLY EXISTS
#
CREATE TABLE t1 SELECT 1 AS fld1, 'A' AS fld2;
CREATE TABLE t2 (fld3 INT, fld4 CHAR(1));
CREATE VIEW v1 AS SELECT * FROM t1;
CREATE TRIGGER t1_au AFTER UPDATE ON t1
FOR EACH ROW INSERT INTO t2 VALUES (new.fld1, new.fld2);
CREATE FUNCTION f1() RETURNS INT
BEGIN
UPDATE v1 SET fld2='B' WHERE fld1=1;
RETURN row_count();
END !
# Without the patch, an error was getting reported.
SELECT f1();
f1()
1
DROP FUNCTION f1;
DROP VIEW v1;
DROP TABLE t1,t2;

26
mysql-test/t/sp-prelocking.test
View File

@ -388,3 +388,29 @@ DROP TABLE t1, t2;
--echo End of 5.0 tests
--echo #
--echo # Bug#21142859: FUNCTION UPDATING A VIEW FAILS TO FIND TABLE THAT ACTUALLY EXISTS
--echo #
CREATE TABLE t1 SELECT 1 AS fld1, 'A' AS fld2;
CREATE TABLE t2 (fld3 INT, fld4 CHAR(1));
CREATE VIEW v1 AS SELECT * FROM t1;
CREATE TRIGGER t1_au AFTER UPDATE ON t1
FOR EACH ROW INSERT INTO t2 VALUES (new.fld1, new.fld2);
DELIMITER !;
CREATE FUNCTION f1() RETURNS INT
BEGIN
UPDATE v1 SET fld2='B' WHERE fld1=1;
RETURN row_count();
END !
DELIMITER ;!
--echo # Without the patch, an error was getting reported.
SELECT f1();
DROP FUNCTION f1;
DROP VIEW v1;
DROP TABLE t1,t2;

11
sql/sql_base.cc
View File

@ -1,4 +1,4 @@
/* Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
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
@ -5211,6 +5211,15 @@ handle_view(THD *thd, Query_tables_list *prelocking_ctx,
&table_list->view->sroutines_list,
table_list->top_table());
}
/*
If a trigger was defined on one of the associated tables then assign the
'trg_event_map' value of the view to the next table in table_list. When a
Stored function is invoked, all the associated tables including the tables
associated with the trigger are prelocked.
*/
if (table_list->trg_event_map && table_list->next_global)
table_list->next_global->trg_event_map= table_list->trg_event_map;
return FALSE;
}