Percona Server moved to https://jira.percona.com/projects/PS

Extra writes to slave_worker_info table with duplicate GTIDs

Series 5.7
Bug #1712911

Bug #1712911 reported by Sveta Smirnova on 2017-08-24

8

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	Percona Server moved to https://jira.percona.com/projects/PS	Status tracked in 5.7
	5.5	Invalid	Undecided	Unassigned
	5.6	Invalid	Undecided	Unassigned
	5.7	Triaged	Medium	Unassigned

Bug Description

After fix of bug #1669928 if one uses slave-parallel-workers > 1 table slave_worker_info gets updated each time it receives GTID no matter if same GTID was already applied or not.

How to repeat:

1. Start 1 mysqld server (master)
2. Create 1 or more slaves of 1
3. Create one more slave of 1 and of 2 using multiple channels
4. Run write load on 1
5. Compare number of writes to table slave_worker_info on 2 and 3

Suggested fix:

Update slave_worker_info only once for each of unique GTIDs

Tags:

Revision history for this message

Sveta Smirnova (svetasmirnova) wrote on 2017-08-24:

#1

Upstream bug is still https://bugs.mysql.com/bug.php?id=85141, linked with bug #1669928, because it is still not fixed.

Revision history for this message

Sveta Smirnova (svetasmirnova) wrote on 2017-08-24:

#2

test case for MTR Edit (2.5 KiB, text/plain)

Revision history for this message

Sveta Smirnova (svetasmirnova) wrote on 2017-08-24:

#3

configuration file Edit (493 bytes, text/plain)

Laurynas Biveinis (laurynas-biveinis) on 2017-08-25

tags:

added: performance

Revision history for this message

Sveta Smirnova (svetasmirnova) wrote on 2017-08-28:

#4

Better test case for MTR Edit (2.6 KiB, text/plain)

Revision history for this message

Sveta Smirnova (svetasmirnova) wrote on 2017-08-29:

#5

Workaround: convert slave_worker_info to MyISAM storage engine. You will loose ability to monitor status of workers however.

Revision history for this message

Shahriyar Rzayev (rzayev-sehriyar) wrote on 2018-01-25:

#6

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-1819

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