Tales From A Lazy Fat DBA

Hi Guys,

Recently while working on PostgreSQL Version 13 I have identified few new changes related with the wait events, particularly related with recovery in order to make the names and what they are more consistent.

For all who are new to events, they can tell you a lot about query and system performance, specially scenarios like .. why a query isn’t making progress ? – One example of a wait event may be IO / DataFileRead, which points that a process is currently waiting for data to be read from disk or the page cache.

So, talking about those waits, first one is event ‘RecoveryWalAll‘ which tells recovery is waiting for WAL from a stream, that could be from any kind of source i.e. local, archive or stream, is now changed to ‘RecoveryWalStream’.

Another one is ‘RecoveryWalStream‘ which can help you to make sure that each standby does not have more WAL to replay or helps to identify what is waiting for WAL from a stream at recovery, is now changed/renamed to RecoveryRetrieveRetryInterval. I have also noticed a change in event class or category of RecoveryRetrieveRetryInterval to Timeout from Activity.

Hope It Helps
Prashant Dixit