Re: Tid scan improvements
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Edmund Horner <ejrh00@gmail.com>
Cc: David Rowley <david.rowley@2ndquadrant.com>,
Tomas Vondra <tomas.vondra@2ndquadrant.com>,
PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2018-12-21T03:31:16Z
Lists: pgsql-hackers
Edmund Horner <ejrh00@gmail.com> writes: > For the forward scan, I seem to recall, from your merge join example, > that it's useful to set the pathkeys even when there are no > query_pathkeys. We just have to unconditionally set them so that the > larger plan can make use of them. No. Look at indxpath.c: it does not worry about pathkeys unless has_useful_pathkeys is true, and it definitely does not generate pathkeys that don't get past truncate_useless_pathkeys. Those functions are responsible for worrying about whether mergejoin can use the pathkeys. It's not tidpath.c's job to outthink them. regards, tom lane
Commits
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Add TID Range Scans to support efficient scanning ranges of TIDs
- bb437f995d47 14.0 landed
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Improve planner's selectivity estimates for inequalities on CTID.
- f7111f72d2fd 12.0 landed