postgres.git / summary / log / commit / refs

commit    8f724002e2fe0e415f5a603462440d2f297f287c
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 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/backend/access/gist/gistscan.c b/src/backend/access/gist/gistscan.c
index 058544e2ae2..f5d8a01fe5a 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/builtins.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 */


[parent: 7db45167ccf5]