MySQL Bugs: #104785: backup lock causes binlog_expire_logs_seconds invalid when the binlog is flushed

Bug #104785	backup lock causes binlog_expire_logs_seconds invalid when the binlog is flushed
Submitted:	1 Sep 2021 8:20	Modified:	2 Sep 2021 15:30
Reporter:	chengqing hu	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: Replication	Severity:	S3 (Non-critical)
Version:	MySQL8.0.26	OS:	Any
Assigned to:		CPU Architecture:	Any

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Description:
The backup lock causes binlog_expire_logs_seconds to become invalid when binlog is flushed.

How to repeat:
1. set global binlog_expire_logs_seconds=10
2. flush binary logs;flush binary logs;flush binary logs;
3. wait 10s
4. LOCK INSTANCE FOR BACKUP;
5. show master logs;
6. flush binary logs;
7. show master logs;
you can see the expired binary log has not been removed.

Suggested fix:
"flush tables with read lock" won't cause this problem.So i don’t think "LOCK INSTANCE FOR BACKUP" should be.

Hi thanks for your report. I'm sure we have this bug already logged in but I can't find it. Verified as described.

thanks