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BUG#13874553: rpl.rpl_stop_slave fails sporadically on pb2

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The test case makes use of the fine DEBUG_SYNC facility. Furthermore,
since it needs synchronization on internal threads (dump and SQL
threads) the server code has DEBUG_SYNC commands internally deployed
and activated through the DBUG_EXECUTE_IF macro. The internal
DBUG_SYNC commands are then controlled from the test case through the
DEBUG variable.

There were three problems around the DEBUG + DEBUG_SYNC facility
usage:

1. When signaling the SQL thread to continue, the test would reset
   immediately the DEBUG_SYNC variable. This could mean that the SQL
   thread might loose the signal and continue to wait forever;

2. A similar scenario was happening with the dump thread on the
   master. This thread was instructed to wait, and later it would be
   signaled to continue, but immediately after the DEBUG_SYNC would be
   reset. This could lead to the dump thread missing the signal and
   wait forever;

3. The test was not cleaning itself up with respect to the
   instrumentation of the dump thread. This would leave the
   conditional execution of an internal DEBUG_SYNC command active
   (through the usage of DBUG_EXECUTE_IF). 

We fix #1 and #2 by waiting for the threads to receive the signal and
only then issue the reset. We fix #3 by reseting the DEBUG variable,
thus deactivating the dump thread internal DEBUG_SYNC command.
This commit is contained in:
Luis Soares 2014-06-26 12:54:27 +01:00
parent c6c2d43a60
commit 5111df0814
3 changed files with 38 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
mysql-test/extra/rpl_tests/rpl_stop_slave.test
View File

@ -42,6 +42,10 @@ send STOP SLAVE SQL_THREAD;
connection slave1;
--echo # To resume slave SQL thread
SET DEBUG_SYNC= 'now SIGNAL signal.continue';
# wait for the sql thread to come out of the
# waiting phase before resetting the signals
--let $wait_condition= select count(*)=0 from information_schema.processlist where state LIKE '%debug sync point%' and info LIKE '%INSERT INTO t1 VALUES (1)%'
--source include/wait_condition.inc
SET DEBUG_SYNC= 'RESET';
--echo

9
mysql-test/suite/rpl/r/rpl_stop_slave.result
View File

@ -93,10 +93,12 @@ DROP TABLE t1, t2;
CREATE TABLE t1 (c1 INT KEY, c2 INT) ENGINE=InnoDB;
CREATE TABLE t2 (c1 INT) ENGINE=MyISAM;
INSERT INTO t1 VALUES(1, 1);
include/stop_slave.inc
[connection master]
include/stop_dump_threads.inc
SET GLOBAL debug= 'd,dump_thread_wait_before_send_xid';
[connection slave]
include/restart_slave.inc
include/start_slave.inc
BEGIN;
UPDATE t1 SET c2 = 2 WHERE c1 = 1;
[connection master]
@ -115,8 +117,11 @@ SET DEBUG_SYNC= 'RESET';
[connection slave]
include/wait_for_slave_to_stop.inc
[connection slave1]
[connection master]
SET GLOBAL debug= '$debug_save';
include/stop_dump_threads.inc
[connection slave1]
include/start_slave.inc
[connection master]
DROP TABLE t1, t2;
SET GLOBAL debug= $debug_save;
include/rpl_end.inc

29
mysql-test/suite/rpl/t/rpl_stop_slave.test
View File

@ -72,14 +72,17 @@ CREATE TABLE t2 (c1 INT) ENGINE=MyISAM;
INSERT INTO t1 VALUES(1, 1);
sync_slave_with_master;
--source include/stop_slave.inc
--source include/rpl_connection_master.inc
# make sure that there are no zombie threads
--source include/stop_dump_threads.inc
let $debug_save= `SELECT @@GLOBAL.debug`;
SET GLOBAL debug= 'd,dump_thread_wait_before_send_xid';
--source include/rpl_connection_slave.inc
source include/restart_slave_sql.inc;
--source include/start_slave.inc
BEGIN;
UPDATE t1 SET c2 = 2 WHERE c1 = 1;
@ -91,6 +94,10 @@ INSERT INTO t2 VALUES(1);
UPDATE t1 SET c2 = 3 WHERE c1 = 1;
COMMIT;
# wait for the dump thread reach the sync point
--let $wait_condition= select count(*)=1 from information_schema.processlist where state LIKE '%debug sync point%' and command='Binlog Dump'
--source include/wait_condition.inc
--source include/rpl_connection_slave1.inc
let $show_statement= SHOW PROCESSLIST;
let $field= Info;
@ -103,7 +110,12 @@ send STOP SLAVE;
ROLLBACK;
--source include/rpl_connection_master.inc
SET DEBUG_SYNC= 'now SIGNAL signal.continue';
# wait for the dump thread to come out of the
# waiting phase before resetting the signals
--let $wait_condition= select count(*)=0 from information_schema.processlist where state LIKE '%debug sync point%' and command='Binlog Dump'
--source include/wait_condition.inc
SET DEBUG_SYNC= 'RESET';
--source include/rpl_connection_slave.inc
@ -111,9 +123,22 @@ source include/wait_for_slave_to_stop.inc;
--source include/rpl_connection_slave1.inc
reap;
# Slave has stopped, thence lets make sure that
# we kill the zombie dump threads. Also, make
# sure that we disable the DBUG_EXECUTE_IF
# that would set the dump thread to wait
--source include/rpl_connection_master.inc
SET GLOBAL debug= '$debug_save';
# make sure that there are no zombie threads
--source include/stop_dump_threads.inc
--source include/rpl_connection_slave1.inc
# now the dump thread on the master will start
# from a clean slate, i.e. without the
# DBUG_EXECUTE_IF set
source include/start_slave.inc;
--source include/rpl_connection_master.inc
DROP TABLE t1, t2;
SET GLOBAL debug= $debug_save;
--source include/rpl_end.inc