Postgres Pro
Downloads
Home   >   mailing lists

Re: Which side of a Merge Join gets executed first? Do both sides always get executed? - Mailing list pgsql-performance

From Frédéric Yhuel
Subject Re: Which side of a Merge Join gets executed first? Do both sides always get executed?
Date
Msg-id e7791357-4f29-4396-8419-daa14cbd52c6@dalibo.com
Whole thread Raw
In response to Which side of a Merge Join gets executed first? Do both sides always get executed?  (Jerry Brenner <jbrenner@guidewire.com>)
Responses Re: Which side of a Merge Join gets executed first? Do both sides always get executed?  (Jerry Brenner <jbrenner@guidewire.com>)
List pgsql-performance
Tree view 

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

pgsql-performance by date:

Previous
From: Frédéric Yhuel
Date:
Subject: Re: Which side of a Merge Join gets executed first? Do both sides always get executed?
Next
From: Jerry Brenner
Date:
Subject: Re: Which side of a Merge Join gets executed first? Do both sides always get executed?