On Tue, Mar 1, 2016 at 7:40 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > Tobias Florek <postgres@ibotty.net> writes: >> When creating an index to use for an ORDER BY clause, a simple query >> starts to return more results than expected. See the following detailed >> log. > > Ugh. That is *badly* broken. I thought maybe it had something to do with > the "abbreviated keys" work, but the same thing happens if you change the > numeric column to integer, so I'm not very sure where to look. Who's > touched btree key comparison logic lately? > > (Problem is reproducible in 9.5 and HEAD, but not 9.4.)
Bisects down to:
606c0123d627b37d5ac3f7c2c97cd715dde7842f is the first bad commit commit 606c0123d627b37d5ac3f7c2c97cd715dde7842f Author: Simon Riggs <simon@2ndQuadrant.com> Date: Tue Nov 18 10:24:55 2014 +0000
Reduce btree scan overhead for < and > strategies
For <, <=, > and >= strategies, mark the first scan key as already matched if scanning in an appropriate direction. If index tuple contains no nulls we can skip the first re-check for each tuple.
Author: Rajeev Rastogi Reviewer: Haribabu Kommi Rework of the code and comments by Simon Riggs
Mea culpa.
Looks like we'll need a new release as soon as we can lock down a fix.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
