From bc67f4189a7a3381db76dbfeafca463187bfe87a 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 c8700f5c9c..c53c802bf8 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)