MySQL Bugs: #88947: Documentation for slave_transaction

Bug #88947	Documentation for slave_transaction_retries not complete
Submitted:	16 Dec 2017 10:49	Modified:	18 Apr 2018 8:57
Reporter:	Daniël van Eeden (OCA)	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.7	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
Page: https://dev.mysql.com/doc/refman/5.7/en/replication-options-slave.html#sysvar_slave_transa...

This doesn't answer these questions:
1. Does 0 mean infinite retries or does that disable retries?
2. What status variable should I monitor?

How to repeat:
Read docs

Suggested fix:
Explicitly state the meaning of 0.

Mention "select * from performance_schema.replication_applier_status"
and/or https://dev.mysql.com/doc/refman/5.7/en/server-status-variables.html#statvar_Slave_retried...

Hello Daniël,

Thank you for the report!

Thanks,
Umesh

Posted by developer:
 
Thanks for pointing this out. The answers are that 0 does disable retries, and the number of retries is shown in the replication_applier_status Performance Schema table.

I've updated the description in 5.7 and 8.0. The 8.0 version now reads:
 Sets the maximum number of times for replication slave SQL threads on a single-threaded or multi-threaded slave to automatically retry failed transactions before stopping. Setting this variable takes effect for all replication channels immediately, including running channels. The default value is 10. Setting the variable to 0 disables automatic retrying of transactions. 
If a replication slave SQL thread fails to execute a transaction because of an InnoDB deadlock or because the transaction's execution time exceeded InnoDB's innodb_lock_wait_timeout, it automatically retries slave_transaction_retries times before stopping with an error. The Performance Schema table replication_applier_status shows the number of retries that took place on each replication channel, in the COUNT_TRANSACTIONS_RETRIES column.

- I also added a reference in the description of the PS table to the system variable.