Re: Vacuum: allow usage of more than 1GB of work mem

From: Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>, Claudio Freire <klaussfreire(at)gmail(dot)com>
Cc: PostgreSQL-Dev <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Vacuum: allow usage of more than 1GB of work mem
Date: 2016-09-04 23:10:36
Message-ID: 13887468-c786-84f4-3265-e8fb8890fc5e@BlueTreble.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On 9/4/16 1:46 AM, Simon Riggs wrote:
>> > The patch also makes vacuum free the dead_tuples before starting
>> > truncation. It didn't seem necessary to hold onto it beyond that
>> > point, and it might help give the OS more cache, especially if work
>> > mem is configured very high to avoid multiple index scans.
> How long does that part ever take? Is there any substantial gain from this?

If you're asking about how long the dealloc takes, we're going to have
to pay that cost anyway when the context gets destroyed/reset, no? Doing
that sooner rather than later certainly seems like a good idea since
we've seen that truncation can take quite some time. Might as well give
the memory back to the OS ASAP.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532) mobile: 512-569-9461

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Marko Tiikkaja 2016-09-04 23:15:29 Re: Change error code for hstore syntax error
Previous Message Jim Nasby 2016-09-04 23:05:27 Re: \timing interval