From 81c5e46c490e2426db243eada186995da5bb0ba7 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Thu, 31 Aug 2017 22:21:21 -0400 Subject: Introduce 64-bit hash functions with a 64-bit seed. This will be useful for hash partitioning, which needs a way to seed the hash functions to avoid problems such as a hash index on a hash partitioned table clumping all values into a small portion of the bucket space; it's also useful for anything that wants a 64-bit hash value rather than a 32-bit hash value. Just in case somebody wants a 64-bit hash value that is compatible with the existing 32-bit hash values, make the low 32-bits of the 64-bit hash value match the 32-bit hash value when the seed is 0. Robert Haas and Amul Sul Discussion: http://postgr.es/m/CA+Tgmoafx2yoJuhCQQOL5CocEi-w_uG4S2xT0EtgiJnPGcHW3g@mail.gmail.com --- src/backend/utils/adt/timestamp.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'src/backend/utils/adt/timestamp.c') diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c index 6fa126d295b..b11d452fc8a 100644 --- a/src/backend/utils/adt/timestamp.c +++ b/src/backend/utils/adt/timestamp.c @@ -2113,6 +2113,11 @@ timestamp_hash(PG_FUNCTION_ARGS) return hashint8(fcinfo); } +Datum +timestamp_hash_extended(PG_FUNCTION_ARGS) +{ + return hashint8extended(fcinfo); +} /* * Cross-type comparison functions for timestamp vs timestamptz @@ -2419,6 +2424,20 @@ interval_hash(PG_FUNCTION_ARGS) return DirectFunctionCall1(hashint8, Int64GetDatumFast(span64)); } +Datum +interval_hash_extended(PG_FUNCTION_ARGS) +{ + Interval *interval = PG_GETARG_INTERVAL_P(0); + INT128 span = interval_cmp_value(interval); + int64 span64; + + /* Same approach as interval_hash */ + span64 = int128_to_int64(span); + + return DirectFunctionCall2(hashint8extended, Int64GetDatumFast(span64), + PG_GETARG_DATUM(1)); +} + /* overlaps_timestamp() --- implements the SQL OVERLAPS operator. * * Algorithm is per SQL spec. This is much harder than you'd think -- cgit v1.2.3