Bug #51648 DBUG_SYNC_POINT is not defined on all platforms and mtr cant pre-check that

DBUG_SYNC_POINT has at least one strong limitation that it's not defined
on all platforms. It has issues cooperating with @@debug.
All in all its functionality is superseded by DEBUG_SYNC facility and
there is no reason to maintain the old less flexible one.

Fixed with adding debug_sync_set_action() function as a facility to set up
a sync-action in the server sources code and re-writing existing simulations
(found 3) to use it.
Couple of tests have been reworked as well.

The patch offers a pattern for setting sync-points in replication threads
where the standard DEBUG_SYNC does not suffice to reach goals.





mysql-test/extra/rpl_tests/rpl_get_master_version_and_clock.test:
  rewriting the test from GET_LOCK()-based to DEBUG_SYNC-based;
  a pattern of usage DEBUG_SYNC for replication testing is provided.
mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result:
  results are changed.
mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test:
  rewriting the test from GET_LOCK()-based to DEBUG_SYNC-based;
  limiting the test to run only with MIXED binlog-format as the test last
  some 10 secs sensitively contributing to the total of tests run.
mysql-test/suite/rpl/t/rpl_show_slave_running.test:
  rewriting the test from GET_LOCK()-based to DEBUG_SYNC-based.
sql/debug_sync.cc:
  adding debug_sync_set_action() function as a facility to set up
  a sync-action in the server sources code.
sql/debug_sync.h:
  externalizing debug_sync_set_action().
sql/item_func.cc:
  purging sources from DBUG_SYNC_POINT.
sql/mysql_priv.h:
  purging sources from DBUG_SYNC_POINT.
sql/slave.cc:
  rewriting failure simulations to base on DEBUG_SYNC rather than GET_LOCK()-based DBUG_SYNC_POINT.
sql/sql_repl.cc:
  removing an orphan failure simulation line because no counterpart in tests existing.

4 files changed, 39 insertions, 42 deletions

diff --git a/mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result b/mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result
index d054cb573d3..a34c536feb8 100644
--- a/mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result
+++ b/mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result
@@ -7,34 +7,24 @@ start slave;
 call mtr.add_suppression("Slave I/O: Master command COM_REGISTER_SLAVE failed: .*");
 call mtr.add_suppression("Fatal error: The slave I/O thread stops because master and slave have equal MySQL server ids; .*");
 call mtr.add_suppression("Slave I/O thread .* register on master");
-SELECT IS_FREE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP");
-IS_FREE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP")
-1
-SELECT GET_LOCK("debug_lock.before_get_UNIX_TIMESTAMP", 1000);
-GET_LOCK("debug_lock.before_get_UNIX_TIMESTAMP", 1000)
-1
-set global debug= 'd,debug_lock.before_get_UNIX_TIMESTAMP';
 stop slave;
+SET @@global.debug= "+d,'debug_lock.before_get_UNIX_TIMESTAMP'";
 start slave;
-SELECT RELEASE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP");
-RELEASE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP")
-1
+slave is going to hang in get_master_version_and_clock
+slave is unblocked
+SET DEBUG_SYNC='now SIGNAL signal.get_unix_timestamp';
 Check network error happened here
 NETWORK ERROR
-SELECT IS_FREE_LOCK("debug_lock.before_get_SERVER_ID");
-IS_FREE_LOCK("debug_lock.before_get_SERVER_ID")
-1
-SELECT GET_LOCK("debug_lock.before_get_SERVER_ID", 1000);
-GET_LOCK("debug_lock.before_get_SERVER_ID", 1000)
-1
-set global debug= 'd,debug_lock.before_get_SERVER_ID';
+set @@global.debug = "-d,'debug_lock.before_get_UNIX_TIMESTAMP'";
 stop slave;
+SET @@global.debug= "+d,'debug_lock.before_get_SERVER_ID'";
 start slave;
-SELECT RELEASE_LOCK("debug_lock.before_get_SERVER_ID");
-RELEASE_LOCK("debug_lock.before_get_SERVER_ID")
-1
+slave is going to hang in get_master_version_and_clock
+slave is unblocked
+SET DEBUG_SYNC='now SIGNAL signal.get_server_id';
 Check network error happened here
 NETWORK ERROR
+set @@global.debug = "-d,'debug_lock.before_get_SERVER_ID'";
 set global debug= '';
 reset master;
 include/stop_slave.inc
@@ -43,3 +33,4 @@ start slave;
 *** must be having the replicate-same-server-id IO thread error ***
 Slave_IO_Errno= 1593
 Slave_IO_Error= Fatal error: The slave I/O thread stops because master and slave have equal MySQL server ids; these ids must be different for replication to work (or the --replicate-same-server-id option must be used on slave but this does not always make sense; please check the manual before using it).
+SET DEBUG_SYNC= 'RESET';
diff --git a/mysql-test/suite/rpl/r/rpl_show_slave_running.result b/mysql-test/suite/rpl/r/rpl_show_slave_running.result
index da26190e76d..598762d5188 100644
--- a/mysql-test/suite/rpl/r/rpl_show_slave_running.result
+++ b/mysql-test/suite/rpl/r/rpl_show_slave_running.result
@@ -4,11 +4,9 @@ reset master;
 reset slave;
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
 start slave;
+SET DEBUG_SYNC= 'RESET';
 include/stop_slave.inc
-SELECT GET_LOCK("debug_lock.before_get_running_status_yes", 1000);
-GET_LOCK("debug_lock.before_get_running_status_yes", 1000)
-1
-set global debug= 'd,debug_lock.before_get_running_status_yes';
+set global debug= 'd,dbug.before_get_running_status_yes';
 Slave_running, Slave_IO_Running, Slave_SQL_Running, must be OFF, NO, NO in three following queries
 SHOW STATUS LIKE 'Slave_running';
 Variable_name	Value
@@ -22,9 +20,7 @@ Variable_name	Value
 Slave_running	OFF
 Slave_IO_Running= No
 Slave_SQL_Running= No
-SELECT RELEASE_LOCK("debug_lock.before_get_running_status_yes");
-RELEASE_LOCK("debug_lock.before_get_running_status_yes")
-1
+SET DEBUG_SYNC='now SIGNAL signal.io_thread_let_running';
 Slave_running, Slave_IO_Running, Slave_SQL_Running must be OFF YES NO in three following queries
 SHOW STATUS LIKE 'Slave_running';
 Variable_name	Value
@@ -39,4 +35,5 @@ Slave_running	ON
 Slave_IO_Running= Yes
 Slave_SQL_Running= Yes
 set global debug= '';
+SET DEBUG_SYNC= 'RESET';
 End of tests
diff --git a/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test b/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
index 24309e8a14a..4a9276d9880 100644
--- a/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
+++ b/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
@@ -16,8 +16,16 @@
 
 source include/master-slave.inc;
 source include/have_debug.inc;
+source include/have_debug_sync.inc;
+
+#
+# The test is not supposed to have any binglog affairs.
+# Hence it's enough it to run only with one binlog format
+#
+source include/have_binlog_format_mixed.inc;
 
 connection slave;
+
 call mtr.add_suppression("Slave I/O: Master command COM_REGISTER_SLAVE failed: .*");
 call mtr.add_suppression("Fatal error: The slave I/O thread stops because master and slave have equal MySQL server ids; .*");
 call mtr.add_suppression("Slave I/O thread .* register on master");
@@ -25,20 +33,16 @@ call mtr.add_suppression("Slave I/O thread .* register on master");
 #Test case 1: Try to get the value of the UNIX_TIMESTAMP from master under network disconnection
 let $debug_saved= `select @@global.debug`;
 
-let $debug_lock= "debug_lock.before_get_UNIX_TIMESTAMP";
-eval SELECT IS_FREE_LOCK($debug_lock);
-eval SELECT GET_LOCK($debug_lock, 1000);
-
-set global debug= 'd,debug_lock.before_get_UNIX_TIMESTAMP';
+# set up two parameters to pass into extra/rpl_tests/rpl_get_master_version_and_clock
+let $dbug_sync_point= 'debug_lock.before_get_UNIX_TIMESTAMP';
+let $debug_sync_action= 'now SIGNAL signal.get_unix_timestamp';
 source extra/rpl_tests/rpl_get_master_version_and_clock.test; 
 
 #Test case 2: Try to get the value of the SERVER_ID from master under network disconnection
 connection slave;
-let $debug_lock= "debug_lock.before_get_SERVER_ID";
-eval SELECT IS_FREE_LOCK($debug_lock);
-eval SELECT GET_LOCK($debug_lock, 1000);
 
-set global debug= 'd,debug_lock.before_get_SERVER_ID';
+let $dbug_sync_point= 'debug_lock.before_get_SERVER_ID';
+let $debug_sync_action= 'now SIGNAL signal.get_server_id';
 source extra/rpl_tests/rpl_get_master_version_and_clock.test;
 
 eval set global debug= '$debug_saved';
@@ -62,4 +66,9 @@ let $last_io_error= query_get_value("show slave status", Last_IO_Error, 1);
 echo Slave_IO_Errno= $last_io_errno;
 echo Slave_IO_Error= $last_io_error;
 
+# cleanup
+
+# is not really necessary but avoids mtr post-run env check warnings
+SET DEBUG_SYNC= 'RESET';
+
 # End of tests
diff --git a/mysql-test/suite/rpl/t/rpl_show_slave_running.test b/mysql-test/suite/rpl/t/rpl_show_slave_running.test
index 62cc311e6b2..bfdd1c279fc 100644
--- a/mysql-test/suite/rpl/t/rpl_show_slave_running.test
+++ b/mysql-test/suite/rpl/t/rpl_show_slave_running.test
@@ -5,14 +5,14 @@
 #
 source include/master-slave.inc;
 source include/have_debug.inc;
+source include/have_debug_sync.inc;
 
 connection slave;
-
+SET DEBUG_SYNC= 'RESET';
 source include/stop_slave.inc;
 let $debug_saved= `select @@global.debug`;
-let $debug_lock= "debug_lock.before_get_running_status_yes";
-eval SELECT GET_LOCK($debug_lock, 1000);
-set global debug= 'd,debug_lock.before_get_running_status_yes';
+set global debug= 'd,dbug.before_get_running_status_yes'; # to block due-started IO
+
 
 # Test 1. Slave is stopped
 
@@ -40,7 +40,7 @@ echo Slave_SQL_Running= $status;
 # Test 3. The slave IO thread is started and got connected to master
 #         and SQL thread is still not started
 
-eval SELECT RELEASE_LOCK($debug_lock);
+SET DEBUG_SYNC='now SIGNAL signal.io_thread_let_running'; # unblock IO thread now
 let $slave_param= Slave_IO_Running;
 let $slave_param_value= YES;
 source include/wait_for_slave_param.inc;
@@ -72,5 +72,5 @@ echo Slave_SQL_Running= $status;
 connection slave;
 
 eval set global debug= '$debug_saved';
-
+SET DEBUG_SYNC= 'RESET';
 --echo End of tests