Fix broken hash function hashbpcharextended().

jeff-davis · jeff-davis · commit 7ac0f8d384a4 · 2022-12-02T14:06:31.000-08:00
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
@@ -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);
