From: Tom Lane <tgl@sss.pgh.pa.us>
To: André Hänsel <andre@webkr.de>
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: Unworkable plan above certain row count
Date: Wed, 27 Apr 2022 22:08:14 -0400
Message-ID: <503301.1651111694@sss.pgh.pa.us> (raw)
In-Reply-To: <035001d85a9a$4dcfd840$e96f88c0$@webkr.de>
References: <035001d85a9a$4dcfd840$e96f88c0$@webkr.de>
=?iso-8859-1?Q?Andr=E9_H=E4nsel?= <andre@webkr.de> writes:
> Now if you change
> INSERT INTO a(a_id) SELECT generate_series(1, 20000);
> to
> INSERT INTO a(a_id) SELECT generate_series(1, 200000);
> i.e. add a zero, the plan becomes [ not a hashed subplan ]
Yeah, it won't hash the subplan if the estimated size of the hash
table exceeds work_mem. In this case, boosting work_mem would be
a mighty good idea.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, andre@webkr.de, pgsql-performance@lists.postgresql.org
Subject: Re: Unworkable plan above certain row count
In-Reply-To: <503301.1651111694@sss.pgh.pa.us>
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