Horton

Re: accounting for memory used for BufFile during hash joins

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, Melanie Plageman <melanieplageman@gmail.com>, hackers <pgsql-hackers@postgresql.org>
Date: 2019-05-07T03:18:28Z
Lists: pgsql-hackers 
Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> Do we actually check how many duplicates are there during planning?

Certainly that's part of the planner's cost estimates ... but it's
only as good as the planner's statistical knowledge.

			regards, tom lane

Commits

  1. Consider BufFiles when adjusting hashjoin parameters