Re: Which side of a Merge Join gets executed first? Do both sides always get executed?

From: Frédéric Yhuel <frederic(dot)yhuel(at)dalibo(dot)com>
To: Jerry Brenner <jbrenner(at)guidewire(dot)com>, pgsql-performance(at)lists(dot)postgresql(dot)org
Subject: Re: Which side of a Merge Join gets executed first? Do both sides always get executed?
Date: 2023-12-20 18:32:47
Message-ID: e7791357-4f29-4396-8419-daa14cbd52c6@dalibo.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

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

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Jerry Brenner 2023-12-20 19:04:28 Re: Which side of a Merge Join gets executed first? Do both sides always get executed?
Previous Message Frédéric Yhuel 2023-12-20 18:05:40 Re: Which side of a Merge Join gets executed first? Do both sides always get executed?