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Re: When Update balloons memory

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Klaudie Willis <Klaudie.Willis@protonmail.com>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2022-01-11T21:15:34Z
Lists: pgsql-bugs, pgsql-general 
On Tue, Jan 11, 2022 at 11:59 AM Peter Geoghegan <pg@bowt.ie> wrote:
> On Tue, Jan 11, 2022 at 11:54 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Pass NULL for that, per 6867f963e:
> >
> > https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=6867f963e#patch2
>
> Will look into that.

Took a look. Not sure that using pull_varnos would represent an
improvement, though. Do you feel strongly about it?

The current approach has the advantage of allowing
index_expression_changed_walker to directly apply an
FirstLowInvalidHeapAttributeNumber offset to each Var's varattno. We
can't just use bms_overlap to check for overlap between the bms
returned by pull_varnos and our updatedColumns bms. It would be
possible to transform the bms returned by pull_varnos to compensate,
of course, but that seems rather awkward

-- 
Peter Geoghegan

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix memory leak in indexUnchanged hint mechanism.

  2. Fix pull_varnos' miscomputation of relids set for a PlaceHolderVar.