Not the answer you need?
Register and ask your own question!

Problems with online gtid deployment

om_marcelom_marcel EntrantInactive User Role Beginner
Hi All,

we are trying to switch from traditional replication to gtid based replication with the online gtid deployment method percona server 5.6 offers.

Before I describe the issue in more detail here are some Information about our setup.
We have 4 mysql instances in a multi tier replication setup running Debian 6 or 8.
Server 1: Master on debian 6 with percona server 5.6.24-72.2-1.squeeze
Server 2: Slave to Server 1 on debian 6 with percona server 5.6.24-72.2-1.squeeze
Server 3: Slave to Server 1 and reporting master on debian 8 with percona server 5.6.27-75.0-1.jessie
Server 4: Slave to Server 3 on debian 8 with percona server 5.6.27-75.0-1.jessie

On Monday we enabled gtid_mode and gtid_deployment_step on Server 4 and a day later on Server 3. Server 1 and 2 are planned to follow next week with a master switch to Server 2, it is also planned to upgrade them to debian 8.
Everything ran smooth until yesterday when Server 4 began to stop processing queries from time to time. Server 3 started today with that behaviour.
strace revealed that percona server scans the entire binlog in these time periods. New connections are possible but as I said no queries are processed until the scan is complete and that can take a few minutes.

Sometimes, but only on Server 3, around the same time as the hang occurs percona server logs this:
[ERROR] Error in Log_event::read_log_event(): read error, data_len: 8191, event_type: 30
[Warning] Error reading GTIDs from binary log: -1
Which is a little strange since server 1 does not have gtid_mode enabled.

One detail that just struck me, our binlog retention is 2 days, it can hardly be a coincidence that the problems appeared 2 days after making the change.


I suspect that gtid_deployment_step is just not build for "long term" use and proceeding with the deployment could solve the problem.
But I can not be sure and thus I'm a bit reluctant to proceed.
The only way back seems to be purging binlogs on Server 3 and 4 because when restarting them with gtid_mode disabled they complain about gtids in the binlog and refuse to replicate …


Can someone confirm my suspicion or can help me in any other way?

Thanks in advance!
Sign In or Register to comment.

MySQL, InnoDB, MariaDB and MongoDB are trademarks of their respective owners.
Copyright ©2005 - 2020 Percona LLC. All rights reserved.