From 0fdf735d977de99551dd4d7910bdc4d75a08608d Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 28 Dec 2010 22:49:57 -0500 Subject: [PATCH] Avoid unexpected conversion overflow in planner for distant date values. The "date" type supports a wider range of dates than int64 timestamps do. However, there is pre-int64-timestamp code in the planner that assumes that all date values can be converted to timestamp with impunity. Fortunately, what we really need out of the conversion is always a double (float8) value; so even when the date is out of timestamp's range it's possible to produce a sane answer. All we need is a code path that doesn't try to force the result into int64. Per trouble report from David Rericha. Back-patch to all supported versions. Although this is surely a corner case, there's not much point in advertising a date range wider than timestamp's if we will choke on such values in unexpected places. --- src/backend/utils/adt/date.c | 33 ++++++++++++++++++++++++++++++++ src/backend/utils/adt/selfuncs.c | 3 +-- src/include/utils/date.h | 2 ++ 3 files changed, 36 insertions(+), 2 deletions(-) diff --git a/src/backend/utils/adt/date.c b/src/backend/utils/adt/date.c index b5dfe08c9b..c97ecf4a1a 100644 --- a/src/backend/utils/adt/date.c +++ b/src/backend/utils/adt/date.c @@ -459,6 +459,39 @@ date2timestamptz(DateADT dateVal) return result; } +/* + * date2timestamp_no_overflow + * + * This is chartered to produce a double value that is numerically + * equivalent to the corresponding Timestamp value, if the date is in the + * valid range of Timestamps, but in any case not throw an overflow error. + * We can do this since the numerical range of double is greater than + * that of non-erroneous timestamps. The results are currently only + * used for statistical estimation purposes. + */ +double +date2timestamp_no_overflow(DateADT dateVal) +{ + double result; + + if (DATE_IS_NOBEGIN(dateVal)) + result = -DBL_MAX; + else if (DATE_IS_NOEND(dateVal)) + result = DBL_MAX; + else + { +#ifdef HAVE_INT64_TIMESTAMP + /* date is days since 2000, timestamp is microseconds since same... */ + result = dateVal * (double) USECS_PER_DAY; +#else + /* date is days since 2000, timestamp is seconds since same... */ + result = dateVal * (double) SECS_PER_DAY; +#endif + } + + return result; +} + /* * Crosstype comparison functions for dates diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 5925a91373..c08310ba41 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -3865,8 +3865,7 @@ convert_timevalue_to_scalar(Datum value, Oid typid) return DatumGetTimestamp(DirectFunctionCall1(abstime_timestamp, value)); case DATEOID: - return DatumGetTimestamp(DirectFunctionCall1(date_timestamp, - value)); + return date2timestamp_no_overflow(DatumGetDateADT(value)); case INTERVALOID: { Interval *interval = DatumGetIntervalP(value); diff --git a/src/include/utils/date.h b/src/include/utils/date.h index 98570e663c..227a7c897e 100644 --- a/src/include/utils/date.h +++ b/src/include/utils/date.h @@ -91,6 +91,8 @@ typedef struct /* date.c */ +extern double date2timestamp_no_overflow(DateADT dateVal); + extern Datum date_in(PG_FUNCTION_ARGS); extern Datum date_out(PG_FUNCTION_ARGS); extern Datum date_recv(PG_FUNCTION_ARGS); -- 2.40.0