Re: PostgreSQL 9.2 high replication lag - Mailing list pgsql-general

From Lucas
Subject Re: PostgreSQL 9.2 high replication lag
Date
Msg-id 9IUyTDCTXb7OhMjGR1ng9s6dxMnIilFs9w0rdKEQWOhWB0SWt-GqiJML-YNZadtZrnppAp0B5aCpY3HZcWvWSMrGEFOLIncUtj2BYm8qOUs=@sud0.nz
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In response to Re: PostgreSQL 9.2 high replication lag  (Ninad Shah <nshah.postgres@gmail.com>)
Responses Re: PostgreSQL 9.2 high replication lag  (Lucas <root@sud0.nz>)
List pgsql-general


Version 9.2 is very old and has a lot of issues related to streaming replication. Additionally, it is already EOL.

Agreed.


Furthermore, max_standby_streaming_delay has no relation with the streaming lag. It's associated with queries conflicting with data. This parameter will not speed up the WAL apply operation.

Yes, I know. But this parameter determines how long the standby server should wait before canceling standby queries that conflict with about-to-be-applied WAL entries. So, there could be lots of queries conflicting with about-to-be-applied WAL entries.
Again, I was not sure about what is causing the delay so I needed to try any possibility.

Kindly consider upgrading to a supported version.

Yes. We have a project in progress to upgrade.

On top of that, I can say that I have restarted the slave and the replication is now normal.
image.png

You can see above that the replication delay is not passing 3 minutes, which is the max_standby_streaming_delay, but the actual average is 5 seconds. So, looks like rebooting the EC2 instance resolved the issue, but I do not know why.
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