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From: Tom Lane <tgl@sss.pgh.pa.us>
To: =?iso-8859-1?Q?Andr=E9_H=E4nsel?= <andre@webkr.de>
cc: pgsql-performance@lists.postgresql.org
Subject: Re: Unworkable plan above certain row count
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=?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