From: Justin Pryzby <pryzby@telsasoft.com>
To: Ivan Voras <ivoras@gmail.com>
Cc: postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: Optimising a two column OR check
Date: Sat, 12 Oct 2019 09:43:36 -0500
Message-ID: <20191012144336.GA4475@telsasoft.com> (raw)
In-Reply-To: <CAF-QHFXQduEoX=ADZh2QYECLdcM1zOuY6=K0cE_DBjhdH3v+WA@mail.gmail.com>
References: <CAF-QHFXQduEoX=ADZh2QYECLdcM1zOuY6=K0cE_DBjhdH3v+WA@mail.gmail.com>
On Sat, Oct 12, 2019 at 04:39:56PM +0200, Ivan Voras wrote:
> With seqscan disabled, I get this plan on 9.6:
> Bitmap Heap Scan on friend (cost=8.42..19.01 rows=14 width=8)
...
> I expected to get an index-only scan in this situation, as that would be a
> very common query. Is there a way to actually make this sort of query
> resolvable with an index-only scan? Maybe a different table structure would
> help?
The v11 release notes have this relevant item:
https://www.postgresql.org/docs/11/release-11.html
|Allow bitmap scans to perform index-only scans when possible (Alexander Kuzmenkov)
Justin
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To: pgsql-performance@postgresql.org
Cc: pryzby@telsasoft.com, ivoras@gmail.com
Subject: Re: Optimising a two column OR check
In-Reply-To: <20191012144336.GA4475@telsasoft.com>
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