Merge lp:~laurynas-biveinis/percona-server/bug1387951 into lp:percona-server/5.6

[Laurynas Biveinis]

Fix SET STATEMENT ... FOR <statement> crashes:
1) if <statement> needs to commit implicitly and fails (bug 1418049);
2) if <statement> is RW in a RO transaction (bug 1387951);
3) if <statement> is needs to reopen a temp table and fails (bug 1412423).

All three bugs are related and caused by mysql_execute_command jumping
over to an error exit (one goto per each bug) and thus skipping
per_query_variables_backup variable initialization. But the cleanup of
restoring thd->variables from the uninitialzied variable still
happened. Fixed trivially.

This bug was also indicated by a compilation warning:

07:37:58 /home/jenkins/workspace/percona-server-5.6-debian-binary-32/label_exp/debian6-32/percona-server-5.6-5.6.22-71.0/sql/sql_parse.cc: In function 'int mysql_execute_command(THD*)':
07:37:58
/home/jenkins/workspace/percona-server-5.6-debian-binary-32/label_exp/debian6-32/percona-server-5.6-5.6.22-71.0/sql/sql_parse.cc:2609:
error: 'per_query_variables_backup' may be used uninitialized in this
function

fixing which is part of bug 1408232.

Added testcases.

http://jenkins.percona.com/job/percona-server-5.6-param/805/

[Laurynas Biveinis (laurynas-biveinis)]

review: Approve

=== modified file 'mysql-test/r/percona_statement_set.result'
--- mysql-test/r/percona_statement_set.result	2013-09-27 17:47:04 +0000
+++ mysql-test/r/percona_statement_set.result	2015-02-04 16:26:16 +0000
@@ -8,7 +8,7 @@
 DROP PROCEDURE IF EXISTS p5;
 DROP TABLE IF EXISTS STATEMENT;
 '# Setup database'
-CREATE TABLE t1 (v1 INT, v2 INT);
+CREATE TABLE t1 (v1 INT, v2 INT) ENGINE=MyISAM;
 INSERT INTO t1 VALUES (1,2);
 INSERT INTO t1 VALUES (3,4);
 ''
@@ -852,9 +852,36 @@
 '#------------------Test 22-----------------------#'
 CREATE TABLE STATEMENT(a INT);
 DROP TABLE STATEMENT;
+Test for bug 1418049: SET STATEMENT ... FOR <statement> crashes server
+if <statement> needs to commit implicitly and fails
+CREATE TABLE t2 (a INT PRIMARY KEY) ENGINE=InnoDB;
+SET @old_lock_wait_timeout = @@session.lock_wait_timeout;
+SET SESSION lock_wait_timeout = 1;
+BEGIN;
+INSERT INTO t2 VALUES (5);
+FLUSH TABLES WITH READ LOCK;
+SET STATEMENT max_join_size = 0 FOR DROP TABLE t2;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+UNLOCK TABLES;
+COMMIT;
+SET SESSION lock_wait_timeout = @old_lock_wait_timeout;
+Test for bug 1387951: SET STATEMENT ... FOR <statement> crashes server
+if <statement> is RW in a RO transaction
+SET @old_tx_read_only = @@session.tx_read_only;
+SET SESSION tx_read_only = TRUE;
+SET STATEMENT myisam_repair_threads=0 FOR OPTIMIZE TABLE t0;
+ERROR 25006: Cannot execute statement in a READ ONLY transaction.
+SET SESSION tx_read_only = @old_tx_read_only;
+Test for bug 1412423: SET STATEMENT ... FOR <statement> crashes server
+if <statement> needs to re-open a temp table and fails
+CREATE TEMPORARY TABLE t3 (a INT PRIMARY KEY) ENGINE=InnoDB;
+HANDLER t3 OPEN;
+SET STATEMENT max_join_size=1000 FOR SELECT * FROM t3;
+ERROR HY000: Can't reopen table: 't3'
+DROP TABLE t3;
 ''
 '# Cleanup'
-DROP TABLE t1;
+DROP TABLE t1, t2;
 DROP PROCEDURE p1;
 DROP PROCEDURE p2;
 DROP PROCEDURE p3;

=== modified file 'mysql-test/t/percona_statement_set.test'
--- mysql-test/t/percona_statement_set.test	2013-09-27 17:47:04 +0000
+++ mysql-test/t/percona_statement_set.test	2015-02-04 16:26:16 +0000
@@ -1,3 +1,5 @@
+--source include/have_innodb.inc
+--source include/count_sessions.inc
 --echo '# SET STATEMENT ..... FOR ....  TEST'
 ############################ STATEMENT_SET #############################
 #                                                                      #
@@ -28,7 +30,7 @@
 #Set up current database
 ####################################################################
 --echo '# Setup database'
-CREATE TABLE t1 (v1 INT, v2 INT);
+CREATE TABLE t1 (v1 INT, v2 INT) ENGINE=MyISAM;
 INSERT INTO t1 VALUES (1,2);
 INSERT INTO t1 VALUES (3,4);
 --echo ''
@@ -820,11 +822,55 @@
 CREATE TABLE STATEMENT(a INT);
 DROP TABLE STATEMENT;
 
+--echo Test for bug 1418049: SET STATEMENT ... FOR <statement> crashes server
+--echo if <statement> needs to commit implicitly and fails
+
+CREATE TABLE t2 (a INT PRIMARY KEY) ENGINE=InnoDB;
+
+SET @old_lock_wait_timeout = @@session.lock_wait_timeout;
+SET SESSION lock_wait_timeout = 1;
+
+BEGIN;
+INSERT INTO t2 VALUES (5);
+
+--connect(con1,localhost,root,,)
+--connection con1
+FLUSH TABLES WITH READ LOCK;
+
+--connection default
+--error ER_LOCK_WAIT_TIMEOUT
+SET STATEMENT max_join_size = 0 FOR DROP TABLE t2;
+
+--connection con1
+UNLOCK TABLES;
+--disconnect con1
+--connection default
+COMMIT;
+SET SESSION lock_wait_timeout = @old_lock_wait_timeout;
+
+--echo Test for bug 1387951: SET STATEMENT ... FOR <statement> crashes server
+--echo if <statement> is RW in a RO transaction
+SET @old_tx_read_only = @@session.tx_read_only;
+SET SESSION tx_read_only = TRUE;
+--error ER_CANT_EXECUTE_IN_READ_ONLY_TRANSACTION
+SET STATEMENT myisam_repair_threads=0 FOR OPTIMIZE TABLE t0;
+SET SESSION tx_read_only = @old_tx_read_only;
+
+--echo Test for bug 1412423: SET STATEMENT ... FOR <statement> crashes server
+--echo if <statement> needs to re-open a temp table and fails
+CREATE TEMPORARY TABLE t3 (a INT PRIMARY KEY) ENGINE=InnoDB;
+HANDLER t3 OPEN;
+--error ER_CANT_REOPEN_TABLE
+SET STATEMENT max_join_size=1000 FOR SELECT * FROM t3;
+DROP TABLE t3;
+
 --echo ''
 --echo '# Cleanup'
-DROP TABLE t1;
+DROP TABLE t1, t2;
 DROP PROCEDURE p1;
 DROP PROCEDURE p2;
 DROP PROCEDURE p3;
 DROP PROCEDURE p4;
 DROP PROCEDURE p5;
+
+--source include/wait_until_count_sessions.inc

=== modified file 'sql/sql_parse.cc'
--- sql/sql_parse.cc	2015-01-13 09:38:11 +0000
+++ sql/sql_parse.cc	2015-02-04 16:26:16 +0000
@@ -2606,7 +2606,7 @@
   /* have table map for update for multi-update statement (BUG#37051) */
   bool have_table_map_for_update= FALSE;
 #endif
-  struct system_variables *per_query_variables_backup;
+  struct system_variables *per_query_variables_backup= NULL;
   bool reset_timer= false;
 
   DBUG_ENTER("mysql_execute_command");
@@ -5490,7 +5490,10 @@
   if (reset_timer)
     reset_statement_timer(thd);
 
-  if (lex->set_statement && !lex->var_list.is_empty()) {
+  if (per_query_variables_backup) {
+    DBUG_ASSERT(lex->set_statement);
+    DBUG_ASSERT(!lex->var_list.is_empty());
+
     List_iterator_fast<set_var_base> it(thd->lex->var_list);
     set_var *var;