Re: explain HashAggregate to report bucket and memory stats - Mailing list pgsql-hackers

From Jeff Davis
Subject Re: explain HashAggregate to report bucket and memory stats
Date
Msg-id bbe0ba154d7965a2563839b12dd266a0e0d97521.camel@j-davis.com
Whole thread Raw
In response to Re: explain HashAggregate to report bucket and memory stats  (Justin Pryzby <pryzby@telsasoft.com>)
Responses Re: explain HashAggregate to report bucket and memory stats  (Daniel Gustafsson <daniel@yesql.se>)
List pgsql-hackers
On Wed, 2020-04-08 at 16:00 -0500, Justin Pryzby wrote:
> 90% of the initial goal of this patch was handled by instrumentation
> added by
> "hash spill to disk" (1f39bce02), but this *also* adds:
> 
>  - separate accounting for tuples vs hashtable;
>  - number of hash buckets;
>  - handles other agg nodes, and bitmap scan;
> 
> Should I continue pursuing this patch?
> Does it still serve any significant purpose?

Those things would be useful for me trying to tune the performance and
cost model. I think we need to put some of these things under "VERBOSE"
or maybe invent a new explain option to provide this level of detail,
though.

Regards,
    Jeff Davis





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