Re: UPDATEDs slowing SELECTs in a fully cached database - Mailing list pgsql-performance

From Kevin Grittner
Subject Re: UPDATEDs slowing SELECTs in a fully cached database
Date
Msg-id 4E1AEDAB020000250003F1C3@gw.wicourts.gov
Whole thread Raw
In response to Re: UPDATEDs slowing SELECTs in a fully cached database  (lars hofhansl <lhofhansl@yahoo.com>)
Responses Re: UPDATEDs slowing SELECTs in a fully cached database  (lars <lhofhansl@yahoo.com>)
List pgsql-performance
lars hofhansl <lhofhansl@yahoo.com> wrote:

> Yep, I am not seeing the SELECTs slow down (measurably) during
> checkpoints (i.e. when dirty pages are flushed to disk), but only
> during writing of the WAL files.

How about if you do a whole slew of the UPDATEs and then stop those
and run a bunch of SELECTs?  (I don't think I've seen anything
mentioned so far which rules out hint bit rewrites as an issue.)

I see you have tweaked things to balance the writes -- you might
want to try further adjustments to reduce backend writes and see
what happens.

-Kevin

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