From: Tom Lane <tgl@sss.pgh.pa.us>
To: Yavuz Selim Sertoglu <yavuzselim.sertoglu@medyasoft.com.tr>
Cc: pgsql-performance@lists.postgresql.org <pgsql-performance@lists.postgresql.org>
Subject: Re: Gained %20 performance after disabling bitmapscan
Date: Fri, 19 Oct 2018 09:52:04 -0400
Message-ID: <31172.1539957124@sss.pgh.pa.us> (raw)
In-Reply-To: <AM6PR07MB520725A8D1B1287AE313928FD7F90@AM6PR07MB5207.eurprd07.prod.outlook.com>
References: <AM6PR07MB520725A8D1B1287AE313928FD7F90@AM6PR07MB5207.eurprd07.prod.outlook.com>
Yavuz Selim Sertoglu <yavuzselim.sertoglu@medyasoft.com.tr> writes:
> I have a problem with my query. Query always using parallel bitmap heap scan.
Have you messed with the parallel cost parameters? It seems a bit
surprising that this query wants to use parallelism at all.
> Index Cond: (((mukellef_id)::text = '0123456789'::text) AND (kayit_tarihi >= '2018-01-01 00:00:00'::timestamp without time zone) AND (sube_no = '-13'::integer) AND ((defter)::text = 'sm'::text))
If that's your normal query pattern, then this isn't a very good
index design:
> Column | Type | Definition
> --------------+-----------------------------+--------------
> mukellef_id | character varying(12) | mukellef_id
> kayit_tarihi | timestamp without time zone | kayit_tarihi
> sube_no | integer | sube_no
> defter | character varying(4) | defter
> id | bigint | id
The column order should be mukellef_id, sube_no, defter, kayit_tarihi, id
so that the index entries you want are adjacent in the index.
Of course, if you have other queries using this index, you might need
to leave it as-is --- but this is the query you're complaining about...
regards, tom lane
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: tgl@sss.pgh.pa.us, yavuzselim.sertoglu@medyasoft.com.tr, pgsql-performance@lists.postgresql.org
Subject: Re: Gained %20 performance after disabling bitmapscan
In-Reply-To: <31172.1539957124@sss.pgh.pa.us>
* 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