Comments on: Evaluating Checkpointing in PostgreSQL https://www.percona.com/blog/evaluating-checkpointing-in-postgresql/ Mon, 10 Aug 2020 18:18:47 +0000 hourly 1 https://wordpress.org/?v=6.5.2 By: Vadim Tkachenko https://www.percona.com/blog/evaluating-checkpointing-in-postgresql/#comment-10972551 Wed, 29 Jul 2020 15:37:49 +0000 https://www.percona.com/blog/?p=70159#comment-10972551 Mark,

I’ve posted InnoDB results here https://www.percona.com/blog/2020/07/29/checkpointing-in-mysql-and-mariadb/

]]> By: Mark Callaghan https://www.percona.com/blog/evaluating-checkpointing-in-postgresql/#comment-10972541 Tue, 28 Jul 2020 23:48:38 +0000 https://www.percona.com/blog/?p=70159#comment-10972541 When not disabling full page writes to the wal, consider running with sizeof(wal) ~= sizeof(shared buffer). Assuming wal compression doesn’t reduce the size of a page, then the worst case is that each page is written to the wal once so the wal should be large enough to store all pages that are in shared buffers. This might not fix the sawtooth pattern but might make it less frequent.

One thing not mentioned in the previous paragraph is that sizeof(wal) might need to be more than sizeof(shared buffers), by 2X or 3X to satisfy the condition.

It will be interesting to compare Postgres and InnoDB for similar amounts of redo relative to the buffer pool size.

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