Horton

Re: Make MemoryContextMemAllocated() more precise

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Jeff Davis <pgsql@j-davis.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Tomas Vondra <tomas.vondra@postgresql.org>
Date: 2020-03-19T19:26:44Z
Lists: pgsql-hackers 
On Thu, Mar 19, 2020 at 2:11 PM Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:
> My understanding is that this is really just an accounting issue, where
> allocating a block would get us over the limit, which I suppose might be
> an issue with low work_mem values.

Well, the issue is, if I understand correctly, that this means that
MemoryContextStats() might now report a smaller amount of memory than
what we actually allocated from the operating system. That seems like
it might lead someone trying to figure out where a backend is leaking
memory to erroneous conclusions.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Create memory context for HashAgg with a reasonable maxBlockSize.

  2. Specialize MemoryContextMemAllocated().