From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Hackety Man <hacketyman@gmail.com>
To: Pavel Stehule <pavel.stehule@gmail.com>
To: Pgsql Performance <pgsql-performance@lists.postgresql.org>
Cc: Robert Haas <robertmhaas@gmail.com>
Subject: Re: Unexplainable execution time difference between two test functions...one using IF (SELECT COUNT(*) FROM...) and the other using IF EXISTS (SELECT 1 FROM...)
Date: Tue, 17 Apr 2018 22:30:47 +0200
Message-ID: <bd907ab8-74ea-383f-b547-0928154a11ac@2ndquadrant.com> (raw)
In-Reply-To: <CA+1fJ+_t-gX1f9ni26mbxMUX5pv=8dB=jfhaVRK8akjCtgjBkA@mail.gmail.com>
References: <CA+1fJ+8vEq+RWpgpqgaxjwq1AvnRSrm0FFgN2_8VoRUq7=asMA@mail.gmail.com>
<CAFj8pRA5sS+dxBP8ZiDLMw6KUZKtVGa476cgxe5nJ5K1n43xng@mail.gmail.com>
<CA+1fJ+_t-gX1f9ni26mbxMUX5pv=8dB=jfhaVRK8akjCtgjBkA@mail.gmail.com>
On 04/17/2018 04:05 PM, Hackety Man wrote:
> Hi Pavel,
>
> Thanks for sharing that information. I was not aware that the parallel
> query functionality was not yet fully implemented.
>
Nothing is ever "fully implemented". There are always gaps and possible
improvements ;-)
That being said, parallelism opens an entirely new dimension of possible
plans and planning issues.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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Cc: tomas.vondra@2ndquadrant.com, hacketyman@gmail.com, pavel.stehule@gmail.com, pgsql-performance@lists.postgresql.org, robertmhaas@gmail.com
Subject: Re: Unexplainable execution time difference between two test functions...one using IF (SELECT COUNT(*) FROM...) and the other using IF EXISTS (SELECT 1 FROM...)
In-Reply-To: <bd907ab8-74ea-383f-b547-0928154a11ac@2ndquadrant.com>
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