Date: Thu, 19 Mar 2020 01:42:22 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Jeff Davis <pgsql@j-davis.com>
Cc: Andres Freund <andres@anarazel.de>,
	Tomas Vondra <tomas.vondra@2ndquadrant.com>,
	Melanie Plageman <melanieplageman@gmail.com>,
	Heikki Linnakangas <hlinnaka@iki.fi>,
	Taylor Vesely <tvesely@pivotal.io>, Adam Lee <ali@pivotal.io>,
	Melanie Plageman <mplageman@pivotal.io>,
	pgsql-hackers@postgresql.org
Subject: Re: Memory-Bounded Hash Aggregation
Message-ID: <20200319064222.GR26184@telsasoft.com>
References: <20200219191636.gvdywx32kwbix6kd@development>
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 <9759ab2d0c2c28a175e11efe1788d37dc7e1b768.camel@j-davis.com>
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 <5c371df7cee903e8cd4c685f90c6c72086d3a2dc.camel@j-davis.com>
 <20200224232928.45bcjmdxgnobijgi@alap3.anarazel.de>
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On Sun, Mar 15, 2020 at 04:05:37PM -0700, Jeff Davis wrote:
> > +	if (from_tape)
> > +		partition_mem += HASHAGG_READ_BUFFER_SIZE;
> > +	partition_mem = npartitions * HASHAGG_WRITE_BUFFER_SIZE;
> > 
> > => That looks wrong ; should say += ?
> 
> Good catch! Fixed.

> +++ b/src/backend/executor/nodeAgg.c
> @@ -2518,9 +3499,36 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
>  	 */
>  	if (use_hashing)
>  	{
> +		Plan   *outerplan = outerPlan(node);
> +		uint64	totalGroups = 0;
> +		for (i = 0; i < aggstate->num_hashes; i++)
> +			totalGroups = aggstate->perhash[i].aggnode->numGroups;
> +
> +		hash_agg_set_limits(aggstate->hashentrysize, totalGroups, 0,

I realize that I missed the train but .. that looks like another += issue?

Also, Andres was educating me about the range of behavior of "long" type, and I
see now while rebasing that you did the same thing.
https://www.postgresql.org/message-id/20200306175859.d56ohskarwldyrrw%40alap3.anarazel.de

-- 
Justin