From e5d8f3596100da0d38a38513c69e803b7fe7041a Mon Sep 17 00:00:00 2001 From: Alexander Korotkov Date: Sun, 8 Sep 2019 21:07:30 +0300 Subject: [PATCH] Fix handling Inf and Nan values in GiST pairing heap comparator Previously plain float comparison was used in GiST pairing heap. Such comparison doesn't provide proper ordering for value sets containing Inf and Nan values. This commit fixes that by usage of float8_cmp_internal(). Note, there is remaining problem with NULL distances, which are represented as Inf in pairing heap. It would be fixes in subsequent commit. Backpatch to all supported versions. Reported-by: Andrey Borodin Discussion: https://postgr.es/m/CAPpHfdsNvNdA0DBS%2BwMpFrgwT6C3-q50sFVGLSiuWnV3FqOJuQ%40mail.gmail.com Author: Alexander Korotkov Reviewed-by: Heikki Linnakangas Backpatch-through: 9.4 --- src/backend/access/gist/gistscan.c | 7 +++++-- src/test/regress/expected/create_index.out | 10 +++++----- 2 files changed, 10 insertions(+), 7 deletions(-) diff --git a/src/backend/access/gist/gistscan.c b/src/backend/access/gist/gistscan.c index 893d7765b6..636aa62b68 100644 --- a/src/backend/access/gist/gistscan.c +++ b/src/backend/access/gist/gistscan.c @@ -17,6 +17,7 @@ #include "access/gist_private.h" #include "access/gistscan.h" #include "access/relscan.h" +#include "utils/float.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/rel.h" @@ -36,8 +37,10 @@ pairingheap_GISTSearchItem_cmp(const pairingheap_node *a, const pairingheap_node /* Order according to distance comparison */ for (i = 0; i < scan->numberOfOrderBys; i++) { - if (sa->distances[i] != sb->distances[i]) - return (sa->distances[i] < sb->distances[i]) ? 1 : -1; + int cmp = -float8_cmp_internal(sa->distances[i], sb->distances[i]); + + if (cmp != 0) + return cmp; } /* Heap items go before inner pages, to ensure a depth-first search */ diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out index c6d575a2f9..117b11a1a6 100644 --- a/src/test/regress/expected/create_index.out +++ b/src/test/regress/expected/create_index.out @@ -523,16 +523,16 @@ SELECT * FROM point_tbl ORDER BY f1 <-> '0,1'; SELECT * FROM point_tbl ORDER BY f1 <-> '0,1'; f1 ------------------- - (10,10) - (NaN,NaN) (0,0) (1e-300,-1e-300) (-3,4) (-10,0) + (10,10) (-5,-12) (5.1,34.5) - (1e+300,Infinity) + + (NaN,NaN) (10 rows) EXPLAIN (COSTS OFF) @@ -561,15 +561,15 @@ SELECT * FROM point_tbl WHERE f1 IS NOT NULL ORDER BY f1 <-> '0,1'; SELECT * FROM point_tbl WHERE f1 IS NOT NULL ORDER BY f1 <-> '0,1'; f1 ------------------- - (10,10) - (NaN,NaN) (0,0) (1e-300,-1e-300) (-3,4) (-10,0) + (10,10) (-5,-12) (5.1,34.5) (1e+300,Infinity) + (NaN,NaN) (9 rows) EXPLAIN (COSTS OFF)