Re: Bitmap reuse

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: David Rowley <dgrowleyml(at)gmail(dot)com>
Cc: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Bitmap reuse
Date: 2021-07-21 01:32:18
Message-ID: 652080.1626831138@sss.pgh.pa.us
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David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> On Wed, 21 Jul 2021 at 11:25, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Uh .... it's not the "exact same bitmap each time", because the selected
>> rows vary depending on the value of g.i.

> I imagined Jeff was meaning the bitmap from the scan of foo_x_idx, not
> the combined ANDed bitmap from both indexes.

To re-use that, you'd need a way to prevent the upper node from
destructively modifying the tidbitmap.

regards, tom lane

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