Re: [HACKERS] Parallel Hash take II - Mailing list pgsql-hackers

From Andres Freund
Subject Re: [HACKERS] Parallel Hash take II
Date
Msg-id 20171115190545.vloez3zeqc2n5ysv@alap3.anarazel.de
Whole thread Raw
In response to Re: [HACKERS] Parallel Hash take II  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-hackers
Hi,

On 2017-11-15 10:57:35 -0800, Peter Geoghegan wrote:
> > I don't really have a good answer to "but what should we otherwise do",
> > but I'm doubtful this is quite the right answer.
> 
> I think that the work_mem model should be replaced by something that
> centrally budgets memory. It would make sense to be less generous with
> sorts and more generous with hash joins when memory is in short
> supply, for example, and a model like this can make that possible. The
> work_mem model has always forced users to be far too conservative.
> Workloads are very complicated, and always having users target the
> worst case leaves a lot to be desired.

Obviously that's nice and worthwhile goal, but it seems more than a bit
out of reach for this patchset.

Greetings,

Andres Freund


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