postgres.git / summary / log / commit / refs

commit    bc67f4189a7a3381db76dbfeafca463187bfe87a
Author:   Alexander Korotkov <akorotkov@postgresql.org>
Date:     Sun Sep 08 18:07:30 2019 +0000
First released in: 13.0, 9.4.25, 9.5.20, 9.6.16, 10.11, 11.6, 12.0

    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 893d7765b6c..636aa62b680 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 c8700f5c9c6..c53c802bf86 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)


[parent: b6d72ddd5fbf]