From 782be0f7124a7e45acf122c1f4988937b94ddb4e Mon Sep 17 00:00:00 2001 From: Noah Misch Date: Sat, 14 Oct 2023 16:33:51 -0700 Subject: Dissociate btequalimage() from interval_ops, ending its deduplication. Under interval_ops, some equal values are distinguishable. One such pair is '24:00:00' and '1 day'. With that being so, btequalimage() breaches the documented contract for the "equalimage" btree support function. This can cause incorrect results from index-only scans. Users should REINDEX any btree indexes having interval-type columns. After updating, pg_amcheck will report an error for almost all such indexes. This fix makes interval_ops simply omit the support function, like numeric_ops does. Back-pack to v13, where btequalimage() first appeared. In back branches, for the benefit of old catalog content, btequalimage() code will return false for type "interval". Going forward, back-branch initdb will include the catalog change. Reviewed by Peter Geoghegan. Discussion: https://postgr.es/m/20231011013317.22.nmisch@google.com --- src/backend/utils/adt/datum.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'src/backend/utils/adt/datum.c') diff --git a/src/backend/utils/adt/datum.c b/src/backend/utils/adt/datum.c index 7070da1762d..f421024c89a 100644 --- a/src/backend/utils/adt/datum.c +++ b/src/backend/utils/adt/datum.c @@ -43,6 +43,7 @@ #include "postgres.h" #include "access/detoast.h" +#include "catalog/pg_type_d.h" #include "common/hashfn.h" #include "fmgr.h" #include "utils/builtins.h" @@ -385,20 +386,17 @@ datum_image_hash(Datum value, bool typByVal, int typLen) * datum_image_eq() in all cases can use this as their "equalimage" support * function. * - * Currently, we unconditionally assume that any B-Tree operator class that - * registers btequalimage as its support function 4 must be able to safely use - * optimizations like deduplication (i.e. we return true unconditionally). If - * it ever proved necessary to rescind support for an operator class, we could - * do that in a targeted fashion by doing something with the opcintype - * argument. + * Earlier minor releases erroneously associated this function with + * interval_ops. Detect that case to rescind deduplication support, without + * requiring initdb. *------------------------------------------------------------------------- */ Datum btequalimage(PG_FUNCTION_ARGS) { - /* Oid opcintype = PG_GETARG_OID(0); */ + Oid opcintype = PG_GETARG_OID(0); - PG_RETURN_BOOL(true); + PG_RETURN_BOOL(opcintype != INTERVALOID); } /*------------------------------------------------------------------------- -- cgit v1.2.3