From: Jeff Davis <jdavis@postgresql.org>
Date: Thu, 1 Dec 2022 19:08:47 +0000 (-0800)
Subject: Fix broken hash function hashbpcharextended().
X-Git-Tag: REL_16_BETA1~1181
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=7ac0f8d384a4633c6652ae1f6bba40d42d21ec18;p=postgresql.git

Fix broken hash function hashbpcharextended().

Ignore trailing spaces for non-deterministic collations when
hashing.

The previous behavior could lead to tuples falling into the wrong
partitions when hash partitioning is combined with the BPCHAR type and
a non-deterministic collation. Fortunately, it did not affect hash
indexes, because hash indexes do not use extended hash functions.

Decline to backpatch, per discussion.

Discussion: https://postgr.es/m/eb83d0ac7b299eb08f9b900dd08a5a0c5d90e517.camel@j-davis.com
Reviewed-by: Richard Guo, Tom Lane
---

diff --git a/src/backend/utils/adt/varchar.c b/src/backend/utils/adt/varchar.c
index 09c483d6ff8..a63c498181e 100644
--- a/src/backend/utils/adt/varchar.c
+++ b/src/backend/utils/adt/varchar.c
@@ -1086,7 +1086,7 @@ hashbpcharextended(PG_FUNCTION_ARGS)
 			Size		bsize;
 			uint8_t    *buf;
 
-			ulen = icu_to_uchar(&uchar, VARDATA_ANY(key), VARSIZE_ANY_EXHDR(key));
+			ulen = icu_to_uchar(&uchar, keydata, keylen);
 
 			bsize = ucol_getSortKey(mylocale->info.icu.ucol,
 									uchar, ulen, NULL, 0);