RE: max_wal_size and wal_keep_size

["James Pang (chaolpan)" <chaolpan@xxxxxxxxx>]

We want keep more wal to give more room for data replication, in case of some delay , and need old wal data. So wan to set wal_keep_size , and want to increase max_wal-size a lot to make max_wal_size > wal_keep_size (it may > 1TB).

 

James

 

From: Jeff Janes <jeff.janes@xxxxxxxxx>
Sent: Sunday, August 28, 2022 10:53 PM
To: James Pang (chaolpan) <chaolpan@xxxxxxxxx>
Cc: pgsql-admin@xxxxxxxxxxxxxxxxxxxx
Subject: Re: max_wal_size and wal_keep_size

 

On Sun, Aug 28, 2022 at 8:46 AM James Pang (chaolpan) <chaolpan@xxxxxxxxx> wrote:

Hi,

It’s PGv13,  what’s relationship between max_wal_size and wal_keep_size ?  For example, wal_keep_size=200GB(to keep enough wal on disk pg_wal) ,   what’s best value for max_wal_size ?   we want to usage max_wal_size to control checkpoint .

 

The settings are independent.  Do you think your checkpoints are occurring too often or not often enough?  (After an unclean shutdown does it take too long for the system to come back up again?)

 

Cheers,

 

Jeff