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| author | Noah Misch <noah@leadboat.com> | 2023-10-14 16:33:51 -0700 |
|---|---|---|
| committer | Noah Misch <noah@leadboat.com> | 2023-10-14 16:33:54 -0700 |
| commit | bf1c21c4fad033414a99d6205118fbc4d75efa62 (patch) | |
| tree | 53a1639d2b110cb0d8102af9d18d0a537dfd5106 /src/backend/utils/adt/datum.c | |
| parent | 06ff064842832187fce7474e866010d2764a066a (diff) | |
| download | postgresql-bf1c21c4fad033414a99d6205118fbc4d75efa62.tar.gz postgresql-bf1c21c4fad033414a99d6205118fbc4d75efa62.zip | |
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
Diffstat (limited to 'src/backend/utils/adt/datum.c')
| -rw-r--r-- | src/backend/utils/adt/datum.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/src/backend/utils/adt/datum.c b/src/backend/utils/adt/datum.c index 9f06ee7626f..251dd23ca81 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); } /*------------------------------------------------------------------------- |