From: Frédéric Yhuel <frederic.yhuel@dalibo.com>
To: Jerry Brenner <jbrenner@guidewire.com>
To: pgsql-performance@lists.postgresql.org
Subject: Re: Which side of a Merge Join gets executed first? Do both sides always get executed?
Date: Wed, 20 Dec 2023 19:32:47 +0100
Message-ID: <e7791357-4f29-4396-8419-daa14cbd52c6@dalibo.com> (raw)
In-Reply-To: <CACoKFYQLgfOYnEGKytSZOQ7hrpdcGgk0jn22jRsZCU9aChUnCw@mail.gmail.com>
References: <CACoKFYQLgfOYnEGKytSZOQ7hrpdcGgk0jn22jRsZCU9aChUnCw@mail.gmail.com>
Le 20/12/2023 à 15:40, Jerry Brenner a écrit :
> Whichever side gets executed first, is the execution of the side that
> would be second get short circuited if 0 rows are returned by the first
> side?
Indeed, if 0 rows are returned from the outer relation, the scan of the
inner relation is never executed.
Best regards,
Frédéric
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To: pgsql-performance@postgresql.org
Cc: frederic.yhuel@dalibo.com, jbrenner@guidewire.com, pgsql-performance@lists.postgresql.org
Subject: Re: Which side of a Merge Join gets executed first? Do both sides always get executed?
In-Reply-To: <e7791357-4f29-4396-8419-daa14cbd52c6@dalibo.com>
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