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MDEV-38829: semisync wait fix #5487

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MDEV-38829: semisync wait fix #5487

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18 changes: 18 additions & 0 deletions mysql-test/suite/rpl/r/mdev38829_semisync_write_fail.result
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Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
call mtr.add_suppression("Write to binary log failed*");
SET GLOBAL rpl_semi_sync_master_enabled = 1;
SET GLOBAL rpl_semi_sync_master_wait_point = 'AFTER_SYNC';
set @saved_dbug = @@global.debug_dbug;
SET GLOBAL debug_dbug='d,injecting_fault_writing';
CREATE TABLE t1 (i INT);
CREATE TABLE t1 (i INT);
ERROR HY000: Error writing file 'master-bin' ((errno: #)
set @@global.debug_dbug = @saved_dbug;
SELECT 1;
1
1
SHOW STATUS LIKE 'Rpl_semi_sync_master_status';
Variable_name Value
Rpl_semi_sync_master_status ON
SET GLOBAL rpl_semi_sync_master_enabled = 0;
SET GLOBAL rpl_semi_sync_master_wait_point = DEFAULT;
DROP TABLE IF EXISTS t1;
36 changes: 36 additions & 0 deletions mysql-test/suite/rpl/t/mdev38829_semisync_write_fail.test
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Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
#
# MDEV-38829: Assertion `rpl_semi_sync_master_off_times >
# thd->expected_semi_sync_offs' failed in Repl_semi_sync_master::commit_trx()
#
# A failed direct binlog write (write_gtid_event()/write_event() returning an
# error) left semisync registration skipped, but the semisync wait
# (wait_after_sync() -> commit_trx()) still ran unconditionally. commit_trx()
# then found no entry for the transaction and asserted that the only
# possible cause was a concurrent switch_off()/switch_on(), which is false
# here -- the entry was simply never registered.
#
# Verify that a failed direct binlog write no longer triggers a semisync
# wait for a transaction that was never registered: the query should just
# return a clean write error, and the server must remain fully responsive
# (in particular, no assertion failure / crash).
#
--source include/have_debug.inc
--source include/have_binlog_format_mixed_or_statement.inc

call mtr.add_suppression("Write to binary log failed*");

SET GLOBAL rpl_semi_sync_master_enabled = 1;
SET GLOBAL rpl_semi_sync_master_wait_point = 'AFTER_SYNC';

--let $query= CREATE TABLE t1 (i INT)
--source include/binlog_inject_error.inc

# The server must still be fully alive and responsive here -- this is the
# actual regression check: pre-fix, the statement above aborts the
# (debug-build) server via DBUG_ASSERT instead of returning cleanly.
SELECT 1;
SHOW STATUS LIKE 'Rpl_semi_sync_master_status';

SET GLOBAL rpl_semi_sync_master_enabled = 0;
SET GLOBAL rpl_semi_sync_master_wait_point = DEFAULT;
DROP TABLE IF EXISTS t1;
3 changes: 2 additions & 1 deletion sql/log.cc
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Expand Up @@ -7259,7 +7259,8 @@ bool MYSQL_BIN_LOG::write(Log_event *event_info, my_bool *with_annotate)
mysql_mutex_assert_owner(&LOCK_after_binlog_sync);
mysql_mutex_assert_not_owner(&LOCK_commit_ordered);
#ifdef HAVE_REPLICATION
if (repl_semisync_master.wait_after_sync(log_file_name, offset))
if (likely(!error) &&
repl_semisync_master.wait_after_sync(log_file_name, offset))
{
error=1;
/* error is already printed inside hook */
Expand Down