Bug#22897202: RPL_IO_THD_WAIT_FOR_DISK_SPACE HAS OCCASIONAL

FAILURES

Analysis:
=========
Test script is not ensuring that "assert_grep.inc" should be
called only after 'Disk is full' error is written to the
error log.

Test checks for "Queueing master event to the relay log"
state. But this state is set before invoking 'queue_event'.
Actual 'Disk is full' error happens at a very lower level.
It can happen that we might even reset the debug point
before even the actual disk full simulation occurs and the
"Disk is full" message will never appear in the error log.

In order to guarentee that we must have some mechanism where
in after we write "Disk is full" error messge into the error
log we must signal the test to execute SSS and then reset
the debug point. So that test is deterministic.

Fix:
===
Added debug sync point to make script deterministic.

1 files changed, 8 insertions, 0 deletions

diff --git a/sql/log.cc b/sql/log.cc
index eab9a118147..a7f05905514 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -4452,6 +4452,14 @@ bool MYSQL_BIN_LOG::appendv(Master_info* mi, const char* buf, uint len,...)
     sufficient to block SQL thread when IO thread is updating relay log here.
   */
   mysql_mutex_unlock(&mi->data_lock);
+  DBUG_EXECUTE_IF("simulate_io_thd_wait_for_disk_space",
+                  {
+                  const char act[]= "disk_full_reached SIGNAL parked";
+                  DBUG_ASSERT(opt_debug_sync_timeout > 0);
+                  DBUG_ASSERT(!debug_sync_set_action(current_thd,
+                                                     STRING_WITH_LEN(act)));
+                  };);
+
   do
   {
     if (my_b_append(&log_file,(uchar*) buf,len))