From: MichaelDBA <MichaelDBA@sqlexec.com>
To: postgres performance list <pgsql-performance@postgresql.org>
Cc: Jeff Janes <jeff.janes@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>
Cc: Ivan Voras <ivoras@gmail.com>
Cc: Andrew Gierth <andrew@tao11.riddles.org.uk>
Subject: Re: Optimising a two column OR check
Date: Sat, 12 Oct 2019 11:45:45 -0400
Message-ID: <0517fa14-6a74-bcec-0655-9e240618c46f@sqlexec.com> (raw)
In-Reply-To: <25d9306a-d0e9-ed82-3128-bff469f09aed@sqlexec.com>
References: <CAF-QHFXQduEoX=ADZh2QYECLdcM1zOuY6=K0cE_DBjhdH3v+WA@mail.gmail.com>
<20191012144336.GA4475@telsasoft.com>
<CAMkU=1w1F0t7c78mJMF7DdBbk50aGy3-AROGzcbdPrS0ApmGAA@mail.gmail.com>
<a0ab3bae-6a5d-b2ea-b3a0-cbcff72f394f@sqlexec.com>
<87y2xqvv1x.fsf@news-spur.riddles.org.uk>
<25d9306a-d0e9-ed82-3128-bff469f09aed@sqlexec.com>
Perhaps the fix by Alexander Kuzmenkov in V11 added this VM
consideration for having a preference of bitmap index scan over an index
only scan. Looks like I'm goin' down the rabbit hole...
Regards,
Michael Vitale
MichaelDBA wrote on 10/12/2019 11:35 AM:
> Nope, vacuumed it and still got the bitmap index scans.
>
> Andrew Gierth wrote on 10/12/2019 11:33 AM:
>>>>>>> "MichaelDBA" == MichaelDBA <MichaelDBA@sqlexec.com> writes:
>> MichaelDBA> BTW, to Andrew, the UNION ALL alternative still results in
>> MichaelDBA> bitmap index scans from my testing.
>>
>> You probably forgot to vacuum the table.
>>
>
>
>
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: pgsql-performance@postgresql.org
Cc: MichaelDBA@sqlexec.com, jeff.janes@gmail.com, pryzby@telsasoft.com, ivoras@gmail.com, andrew@tao11.riddles.org.uk
Subject: Re: Optimising a two column OR check
In-Reply-To: <0517fa14-6a74-bcec-0655-9e240618c46f@sqlexec.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox