MySQL Bugs: #37387: Relay log not sync:ed to disk

Bug #37387	Relay log not sync:ed to disk
Submitted:	13 Jun 2008 9:09	Modified:	3 Jun 2009 15:53
Reporter:	Mats Kindahl	Email Updates:
Status:	Duplicate	Impact on me:	None
Category:	MySQL Server: Replication	Severity:	S3 (Non-critical)
Version:	6.0	OS:	Any
Assigned to:	Assigned Account	CPU Architecture:	Any

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Description:
When an event is received from the master by the I/O thread and subsequently written to the relay log, the relay log is not sync:ed to disk, which makes a crash potentially lose information.

Note that the relay log is usually considered as a buffer, so data in those files should normally be considered as volatile, but for cases where the relay log is expected to represent durable storage, there is a need for a sync.

How to repeat:
Read the code.

Suggested fix:
Add a sync option for the relay log similar to how it works for the binary log on the master.

Fixed in 6.0 by  --sync-relay-log of  Bug#35542 patch.