#At file:///home/lsoares/Workspace/mysql-server/bugfix/23300/6.0-bt/ based on revid:joro@stripped
3010 Luis Soares 2009-02-10
BUG#23300: Slow query log on slave does not log slow replicated statements
When using replication, the slave will not log any slow query logs queries
replicated from the master, even if the option "--slow-query-log" is set
and these take more than "log_query_time" to execute.
In order to log slow queries in replicated thread one needs to set the
--log-slow-slave-statements, so that the SQL thread is initialized with the
correct switch. Although setting this flag correctly configures the slave
thread option to log slow queries, there is an issue with the condition that
is used to check whether to log the slow query or not. When replaying binlog
events the statement contains the SET TIMESTAMP clause which will force the
slow logging condition check to fail. Consequently, the slow query logging
does take place.
This patch addresses this issue by removing the second condition from the
log_slow_statements as it prevents slow queries to be binlogged and seems
to be deprecated.
added:
mysql-test/suite/rpl/r/rpl_slow_query_log.result
mysql-test/suite/rpl/t/rpl_slow_query_log-slave.opt
mysql-test/suite/rpl/t/rpl_slow_query_log.test
modified:
sql/sql_parse.cc
=== added file 'mysql-test/suite/rpl/r/rpl_slow_query_log.result'
--- a/mysql-test/suite/rpl/r/rpl_slow_query_log.result 1970-01-01 00:00:00 +0000
+++ b/mysql-test/suite/rpl/r/rpl_slow_query_log.result 2009-02-10 17:08:11 +0000
@@ -0,0 +1,19 @@
+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+STOP SLAVE;
+SET @old_long_query_time= @@long_query_time;
+SET GLOBAL long_query_time= 2;
+START SLAVE;
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 values(1, 1);
+INSERT INTO t1 values(1, sleep(3));
+DROP TABLE t1;
+Check absence of short query in mysqld-slow.log: Not found.
+Check long query in mysqld-slow.log: INSERT INTO t1 values(1, sleep(3));
+STOP SLAVE;
+SET GLOBAL long_query_time= @old_long_query_time;
+START SLAVE;
=== added file 'mysql-test/suite/rpl/t/rpl_slow_query_log-slave.opt'
--- a/mysql-test/suite/rpl/t/rpl_slow_query_log-slave.opt 1970-01-01 00:00:00 +0000
+++ b/mysql-test/suite/rpl/t/rpl_slow_query_log-slave.opt 2009-02-10 17:08:11 +0000
@@ -0,0 +1 @@
+--force-restart --log-slow-slave-statements
=== added file 'mysql-test/suite/rpl/t/rpl_slow_query_log.test'
--- a/mysql-test/suite/rpl/t/rpl_slow_query_log.test 1970-01-01 00:00:00 +0000
+++ b/mysql-test/suite/rpl/t/rpl_slow_query_log.test 2009-02-10 17:08:11 +0000
@@ -0,0 +1,55 @@
+#
+# BUG#23300: Slow query log on slave does not log slow replicated statements
+#
+# Description:
+# When using replication, the slave will not log any queries replicated from
+# the master).
+#
+# Test is implemented as follows:
+# i) stop slave
+# ii) On slave, set long_query_time to a small value.
+# ii) start slave so that long_query_time variable is picked by sql thread
+# iii) On master, do one short time query and one long time query
+# iv) On slave, sync and check that short lived query is not on
+# mysqld-slow.log and that long lived query is.
+#
+# OBS:
+# This test only runs for statement and mixed binlogging firmat because on
+# row format slow queries do not get slow query logged.
+
+source include/master-slave.inc;
+source include/have_binlog_format_mixed_or_statement.inc;
+
+# Prepare slave for different long_query_time we need to stop the slave
+# and restart it as long_query_time variable is dynamic and, after
+# setting it, it only takes effect on new connections.
+#
+# Reference:
+# http://dev.mysql.com/doc/refman/6.0/en/set-option.html
+connection slave;
+
+STOP SLAVE;
+
+SET @old_long_query_time= @@long_query_time;
+SET GLOBAL long_query_time= 2;
+
+START SLAVE;
+
+connection master;
+
+# create table and insert with query time longer
+# than long_query_time
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 values(1, 1);
+INSERT INTO t1 values(1, sleep(3));
+DROP TABLE t1;
+sync_slave_with_master;
+
+let $MYSQLD_DATADIR= `select @@datadir`;
+--exec echo -n "Check absence of short query in mysqld-slow.log: " && grep "INSERT INTO t1 values(1, 1)" $MYSQLD_DATADIR/../mysqld-slow.log || echo "Not found."
+--exec echo -n "Check long query in mysqld-slow.log: " && grep "INSERT INTO t1 values(1, sleep(3))" $MYSQLD_DATADIR/../mysqld-slow.log || echo "Not found!"
+
+# reset the variables back to the previous value
+STOP SLAVE;
+SET GLOBAL long_query_time= @old_long_query_time;
+START SLAVE;
=== modified file 'sql/sql_parse.cc'
--- a/sql/sql_parse.cc 2009-02-03 09:16:53 +0000
+++ b/sql/sql_parse.cc 2009-02-10 17:08:11 +0000
@@ -1463,9 +1463,24 @@ void log_slow_statement(THD *thd)
/*
Do not log administrative statements unless the appropriate option is
- set; do not log into slow log if reading from backup.
+ set.
+
+ Note for log slow slave statements:
+
+ when slave thread is initialized the thd->enable_slow_log is set according
+ the opt_log_slow_slave_statements. Thence there is only the need to check
+ if this is a slave_thread or not. The more intuitive, but also redundant
+ condition would be:
+
+ thd->enable_slow_log &&
+ (!thd->user_time || (thd->slave_thread && opt_log_slow_slave_statements))
+
+ Furthermore, since we want to preserve the same behavior always, not only in
+ replication thread, but on all threads we disregard the thd->user_time and only
+ check if the slow query log is enabled.
+
*/
- if (thd->enable_slow_log && !thd->user_time)
+ if (thd->enable_slow_log)
{
thd_proc_info(thd, "logging slow query");
ulonglong end_utime_of_query= thd->current_utime();
