BUG#23300: Slow query log on slave does not log slow replicated statements

      
NOTE: this is the backport to next-mr.
      
When using replication, the slave will not log any slow query logs queries 
replicated from the master, even if the option "--log-slow-slave-statements" 
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 will
not 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.

mysql-test/suite/rpl/r/rpl_slow_query_log.result

+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;
+include/stop_slave.inc
+SET @old_log_output= @@log_output;
+SET GLOBAL log_output= 'TABLE';
+SET @old_long_query_time= @@long_query_time;
+SET GLOBAL long_query_time= 2;
+TRUNCATE mysql.slow_log;
+include/start_slave.inc
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 values(1, 1);
+INSERT INTO t1 values(1, sleep(3));
+TRUNCATE mysql.slow_log;
+SELECT 1, sleep(3);
+1	sleep(3)
+1	0
+SELECT 1;
+1
+1
+TRUNCATE mysql.slow_log;
+SET TIMESTAMP= 1;
+SELECT 2, sleep(3);
+2	sleep(3)
+2	0
+SELECT 2;
+2
+2
+TRUNCATE mysql.slow_log;
+SET @old_slow_query_log= @@slow_query_log;
+SET GLOBAL slow_query_log= 'OFF';
+SELECT 3, sleep(3);
+3	sleep(3)
+3	0
+SELECT 3;
+3
+3
+TRUNCATE mysql.slow_log;
+SET GLOBAL slow_query_log= @old_slow_query_log;
+DROP TABLE t1;
+include/stop_slave.inc
+SET GLOBAL long_query_time= @old_long_query_time;
+SET GLOBAL log_output= @old_log_output;
+include/start_slave.inc

mysql-test/suite/rpl/t/rpl_slow_query_log-slave.opt

+--force-restart --log-slow-slave-statements --log-slow-queries

mysql-test/suite/rpl/t/rpl_slow_query_log.test

+#
+# BUG#23300: Slow query log on slave does not log slow replicated statements
+#
+# Description:
+#   The slave should log slow queries replicated from master when
+#   --log-slow-slave-statements is used.
+#
+#   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, on slave
+#         and check that slow query is logged to slow query log but fast query 
+#         is not.
+#     iv) On slave, check that slow queries go into the slow log and fast dont,
+#         when issued through a regular client connection
+#      v) On slave, check that slow queries go into the slow log and fast dont
+#         when we use SET TIMESTAMP= 1 on a regular client connection.
+#     vi) check that when setting slow_query_log= OFF in a connection 'extra2'
+#         prevents logging slow queries in a connection 'extra'
+#
+# 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;
+
+source include/stop_slave.inc;
+
+SET @old_log_output= @@log_output;
+SET GLOBAL log_output= 'TABLE';
+SET @old_long_query_time= @@long_query_time;
+SET GLOBAL long_query_time= 2;
+TRUNCATE mysql.slow_log;
+
+source include/start_slave.inc;
+
+connection master;
+CREATE TABLE t1 (a int, b int); 
+
+# test:
+#   check that slave logs the slow query to the slow log, but not the fast one.
+
+let $slow_query= INSERT INTO t1 values(1, sleep(3));
+let $fast_query= INSERT INTO t1 values(1, 1);
+
+eval $fast_query;
+eval $slow_query;
+sync_slave_with_master;
+
+let $found_fast_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$fast_query'`;
+let $found_slow_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$slow_query'`;
+
+if ($found_fast_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Fast query FOUND in slow query log. Bailing out!";
+}
+
+if (!$found_slow_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Slow query NOT FOUND in slow query log. Bailing out!";
+}
+TRUNCATE mysql.slow_log;
+
+# regular checks for slow query log (using a new connection - 'extra' - to slave)
+
+# test: 
+#   when using direct connections to the slave, check that slow query is logged 
+#   but not the fast one.
+
+connect(extra,127.0.0.1,root,,test,$SLAVE_MYPORT);
+connection extra;
+
+let $fast_query= SELECT 1;
+let $slow_query= SELECT 1, sleep(3);
+
+eval $slow_query;
+eval $fast_query;
+
+let $found_fast_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$fast_query'`;
+let $found_slow_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$slow_query'`;
+
+if ($found_fast_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Fast query FOUND in slow query log. Bailing out!";
+}
+
+if (!$found_slow_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Slow query NOT FOUND in slow query log. Bailing out!";
+}
+TRUNCATE mysql.slow_log;
+
+# test:
+#   when using direct connections to the slave, check that when setting timestamp to 1 the 
+#   slow query is logged but the fast one is not.
+
+let $fast_query= SELECT 2;
+let $slow_query= SELECT 2, sleep(3);
+
+SET TIMESTAMP= 1;
+eval $slow_query;
+eval $fast_query;
+
+let $found_fast_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$fast_query'`;
+let $found_slow_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$slow_query'`;
+
+if ($found_fast_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Fast query FOUND in slow query log. Bailing out!";
+}
+
+if (!$found_slow_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Slow query NOT FOUND in slow query log. Bailing out!";
+}
+TRUNCATE mysql.slow_log;
+
+# test: 
+#   check that when setting the slow_query_log= OFF on connection 'extra2'
+#   prevents connection 'extra' from logging to slow query log.
+
+let $fast_query= SELECT 3;
+let $slow_query= SELECT 3, sleep(3);
+
+connect(extra2,127.0.0.1,root,,test,$SLAVE_MYPORT);
+connection extra2;
+
+SET @old_slow_query_log= @@slow_query_log;
+SET GLOBAL slow_query_log= 'OFF';
+
+connection extra;
+
+eval $slow_query;
+eval $fast_query;
+
+let $found_fast_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$fast_query'`;
+let $found_slow_query= `SELECT count(*) = 1 FROM mysql.slow_log WHERE sql_text like '$slow_query'`;
+
+if ($found_fast_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Fast query FOUND in slow query log when slow_query_log= OFF. Bailing out!";
+}
+
+if ($found_slow_query)
+{
+  SELECT * FROM mysql.slow_log;
+  die "Assertion failed! Slow query FOUND in slow query log when slow_query_log= OFF. Bailing out!";
+}
+TRUNCATE mysql.slow_log;
+
+# clean up: drop tables, reset the variables back to the previous value,
+#           disconnect extra connections
+connection extra2;
+
+SET GLOBAL slow_query_log= @old_slow_query_log;
+
+connection master;
+DROP TABLE t1;
+sync_slave_with_master;
+
+source include/stop_slave.inc;
+
+SET GLOBAL long_query_time= @old_long_query_time;
+SET GLOBAL log_output= @old_log_output;
+
+source include/start_slave.inc;
+
+disconnect extra;
+disconnect extra2;

sql/log.cc

@@ -961,6 +961,7 @@ bool LOGGER::slow_log_print(THD *thd, const char *query, uint query_length,
   uint user_host_len= 0;
   ulonglong query_utime, lock_utime;
 
+  DBUG_ASSERT(thd->enable_slow_log);
   /*
     Print the message to the buffer if we have slow log enabled
   */

sql/sql_parse.cc

@@ -1615,9 +1615,9 @@ 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.
   */
-  if (thd->enable_slow_log && !thd->user_time)
+  if (thd->enable_slow_log)
   {
     ulonglong end_utime_of_query= thd->current_utime();
     thd_proc_info(thd, "logging slow query");