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Properly initialize SortSupport for ORDER BY rechecks in nodeIndexscan.c.

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Fix still another bug in commit 35fcb1b3d: it failed to fully initialize
the SortSupport states it introduced to allow the executor to re-check
ORDER BY expressions containing distance operators.  That led to a null
pointer dereference if the sortsupport code tried to use ssup_cxt.  The
problem only manifests in narrow cases, explaining the lack of previous
field reports.  It requires a GiST-indexable distance operator that lacks
SortSupport and is on a pass-by-ref data type, which among core+contrib
seems to be only btree_gist's interval opclass; and it requires the scan
to be done as an IndexScan not an IndexOnlyScan, which explains how
btree_gist's regression test didn't catch it.  Per bug #14134 from
Jihyun Yu.

Peter Geoghegan

Report: <20160511154904.2603.43889@wrigleys.postgresql.org>
This commit is contained in:
Tom Lane
2016-06-05 11:53:06 -04:00
parent de33af8823
commit 8a859691d5
3 changed files with 37 additions and 2 deletions
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18
contrib/btree_gist/expected/interval.out
View File

@ -89,3 +89,21 @@ SELECT a, a <-> '199 days 21:21:23' FROM intervaltmp ORDER BY a <-> '199 days 21
@ 220 days 19 hours 5 mins 42 secs | @ 21 days -2 hours -15 mins -41 secs
(3 rows)
SET enable_indexonlyscan=off;
EXPLAIN (COSTS OFF)
SELECT a, a <-> '199 days 21:21:23' FROM intervaltmp ORDER BY a <-> '199 days 21:21:23' LIMIT 3;
QUERY PLAN
---------------------------------------------------------------------------
Limit
-> Index Scan using intervalidx on intervaltmp
Order By: (a <-> '@ 199 days 21 hours 21 mins 23 secs'::interval)
(3 rows)
SELECT a, a <-> '199 days 21:21:23' FROM intervaltmp ORDER BY a <-> '199 days 21:21:23' LIMIT 3;
a | ?column?
-------------------------------------+--------------------------------------
@ 199 days 21 hours 21 mins 23 secs | @ 0
@ 183 days 6 hours 52 mins 48 secs | @ 16 days 14 hours 28 mins 35 secs
@ 220 days 19 hours 5 mins 42 secs | @ 21 days -2 hours -15 mins -41 secs
(3 rows)

6
contrib/btree_gist/sql/interval.sql
View File

@ -35,3 +35,9 @@ SELECT count(*) FROM intervaltmp WHERE a > '199 days 21:21:23'::interval;
EXPLAIN (COSTS OFF)
SELECT a, a <-> '199 days 21:21:23' FROM intervaltmp ORDER BY a <-> '199 days 21:21:23' LIMIT 3;
SELECT a, a <-> '199 days 21:21:23' FROM intervaltmp ORDER BY a <-> '199 days 21:21:23' LIMIT 3;
SET enable_indexonlyscan=off;
EXPLAIN (COSTS OFF)
SELECT a, a <-> '199 days 21:21:23' FROM intervaltmp ORDER BY a <-> '199 days 21:21:23' LIMIT 3;
SELECT a, a <-> '199 days 21:21:23' FROM intervaltmp ORDER BY a <-> '199 days 21:21:23' LIMIT 3;