public inbox for [email protected]
help / color / mirror / Atom feedFrom: Greg Sabino Mullane <[email protected]>
To: Jon Zeppieri <[email protected]>
Cc: [email protected]
Subject: Re: Why a bitmap scan in this case?
Date: Thu, 19 Dec 2024 13:38:57 -0500
Message-ID: <CAKAnmmL327t5MRJ2uonQ3JB5bLegRbfa-WtpaTNBnbJ1iVef5Q@mail.gmail.com> (raw)
In-Reply-To: <CAKfDxxzqxm0gS44+4aUDejLq_iszqLJwR+EaM4x2pojrkV58eg@mail.gmail.com>
References: <CAKfDxxzqxm0gS44+4aUDejLq_iszqLJwR+EaM4x2pojrkV58eg@mail.gmail.com>
>
> Why wouldn't it do an index (or, really, an index only) scan in this case
Well, it did do an index scan (and a bitmap scan is a pretty good solution
here), but as to why no indexonly scan, there is probably not enough
assurance that it won't have to hit the heap heavily anyway. Try doing a
SET enable_bitmapscan=0; and re-run with EXPLAIN ANALYZE. If you see a
large number of "Heap Fetches", that could be why. Vacuum the table and try
again after doing SET enable_bitmapscan=1;
Cheers,
Greg
view thread (7+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected], [email protected]
Subject: Re: Why a bitmap scan in this case?
In-Reply-To: <CAKAnmmL327t5MRJ2uonQ3JB5bLegRbfa-WtpaTNBnbJ1iVef5Q@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox