Subject: autovacuum_vacuum_cost_delay

From: "Shenavai, Manuel" <[email-masked]>
Date: Tue, 9 Jul 2024 11:38:40 +0000

Hi everyone,

We are doing some tests with different autovacuum settings.

Looking at autovacuum_vacuum_cost_delay:
https://www.postgresql.org/docs/current/runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-COST-DELAY

Can someone help to understand what a high or low value of this setting really means? Would it be OK to set this to 0? If not, why not?

Thanks in advance &
Best regards,
Manuel

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From: Muhammad Ikram <[email-masked]>
Date: Tue, 9 Jul 2024 18:42:11 +0500

Hi Shenvail,

Based on what I could understand,

Lower value will cause more frequent run of Autovacuum. Will have
less delay between processing data chunks but will put more load on the I/O
system. Autovacuum tasks will complete faster. Cleanup of dead tuples and
blots will be quicker thus increasing performance in the cases where tables
are heavily updated/deleted.

Higher values will result in longer delays between processing data chunks
thus slowing down the completion of autovacuum tasks. Autovacuum will have
less I/O load for its tasks. Database performance will be degraded if
operations are more update/delete intensive. Dead tuples and bloat will
take longer to be cleaned up.
It can be beneficial  for performance of other database operations,
especially if your system is I/O-bound. Can also be helpful when system
resources are less

Regards,
Muhammad Ikram
Bitnine Global.

On Tue, Jul 9, 2024 at 4:38 PM Shenavai, Manuel <[email-masked]>
wrote:

> Can someone help to understand what a high or low value of this setting
> really means? Would it be OK to set this to 0? If not, why not?
>
>
>
> Thanks in advance &
> Best regards,
>
> Manuel
>

-- 
Muhammad Ikram