diff options
Diffstat (limited to 'src/backend/utils/adt/timestamp.c')
| -rw-r--r-- | src/backend/utils/adt/timestamp.c | 50 |
1 files changed, 40 insertions, 10 deletions
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c index 4be1999119c..3f6e0d4497b 100644 --- a/src/backend/utils/adt/timestamp.c +++ b/src/backend/utils/adt/timestamp.c @@ -24,6 +24,7 @@ #include "access/hash.h" #include "access/xact.h" #include "catalog/pg_type.h" +#include "common/int128.h" #include "funcapi.h" #include "libpq/pqformat.h" #include "miscadmin.h" @@ -2288,15 +2289,35 @@ timestamptz_cmp_timestamp(PG_FUNCTION_ARGS) /* * interval_relop - is interval1 relop interval2 + * + * Interval comparison is based on converting interval values to a linear + * representation expressed in the units of the time field (microseconds, + * in the case of integer timestamps) with days assumed to be always 24 hours + * and months assumed to be always 30 days. To avoid overflow, we need a + * wider-than-int64 datatype for the linear representation, so use INT128. */ -static inline TimeOffset + +static inline INT128 interval_cmp_value(const Interval *interval) { - TimeOffset span; + INT128 span; + int64 dayfraction; + int64 days; + + /* + * Separate time field into days and dayfraction, then add the month and + * day fields to the days part. We cannot overflow int64 days here. + */ + dayfraction = interval->time % USECS_PER_DAY; + days = interval->time / USECS_PER_DAY; + days += interval->month * INT64CONST(30); + days += interval->day; - span = interval->time; - span += interval->month * INT64CONST(30) * USECS_PER_DAY; - span += interval->day * INT64CONST(24) * USECS_PER_HOUR; + /* Widen dayfraction to 128 bits */ + span = int64_to_int128(dayfraction); + + /* Scale up days to microseconds, forming a 128-bit product */ + int128_add_int64_mul_int64(&span, days, USECS_PER_DAY); return span; } @@ -2304,10 +2325,10 @@ interval_cmp_value(const Interval *interval) static int interval_cmp_internal(Interval *interval1, Interval *interval2) { - TimeOffset span1 = interval_cmp_value(interval1); - TimeOffset span2 = interval_cmp_value(interval2); + INT128 span1 = interval_cmp_value(interval1); + INT128 span2 = interval_cmp_value(interval2); - return ((span1 < span2) ? -1 : (span1 > span2) ? 1 : 0); + return int128_compare(span1, span2); } Datum @@ -2384,9 +2405,18 @@ Datum interval_hash(PG_FUNCTION_ARGS) { Interval *interval = PG_GETARG_INTERVAL_P(0); - TimeOffset span = interval_cmp_value(interval); + INT128 span = interval_cmp_value(interval); + int64 span64; + + /* + * Use only the least significant 64 bits for hashing. The upper 64 bits + * seldom add any useful information, and besides we must do it like this + * for compatibility with hashes calculated before use of INT128 was + * introduced. + */ + span64 = int128_to_int64(span); - return DirectFunctionCall1(hashint8, Int64GetDatumFast(span)); + return DirectFunctionCall1(hashint8, Int64GetDatumFast(span64)); } /* overlaps_timestamp() --- implements the SQL OVERLAPS operator. |