diff --git a/src/backend/utils/adt/date.c b/src/backend/utils/adt/date.c index eaaffa7137..057051fa85 100644 --- a/src/backend/utils/adt/date.c +++ b/src/backend/utils/adt/date.c @@ -299,20 +299,31 @@ EncodeSpecialDate(DateADT dt, char *str) DateADT GetSQLCurrentDate(void) { - TimestampTz ts; - struct pg_tm tt, - *tm = &tt; - fsec_t fsec; - int tz; + struct pg_tm tm; - ts = GetCurrentTransactionStartTimestamp(); + static int cache_year = 0; + static int cache_mon = 0; + static int cache_mday = 0; + static DateADT cache_date; - if (timestamp2tm(ts, &tz, tm, &fsec, NULL, NULL) != 0) - ereport(ERROR, - (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE), - errmsg("timestamp out of range"))); + GetCurrentDateTime(&tm); - return date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE; + /* + * date2j involves several integer divisions; moreover, unless our session + * lives across local midnight, we don't really have to do it more than + * once. So it seems worth having a separate cache here. + */ + if (tm.tm_year != cache_year || + tm.tm_mon != cache_mon || + tm.tm_mday != cache_mday) + { + cache_date = date2j(tm.tm_year, tm.tm_mon, tm.tm_mday) - POSTGRES_EPOCH_JDATE; + cache_year = tm.tm_year; + cache_mon = tm.tm_mon; + cache_mday = tm.tm_mday; + } + + return cache_date; } /* @@ -322,18 +333,12 @@ TimeTzADT * GetSQLCurrentTime(int32 typmod) { TimeTzADT *result; - TimestampTz ts; struct pg_tm tt, *tm = &tt; fsec_t fsec; int tz; - ts = GetCurrentTransactionStartTimestamp(); - - if (timestamp2tm(ts, &tz, tm, &fsec, NULL, NULL) != 0) - ereport(ERROR, - (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE), - errmsg("timestamp out of range"))); + GetCurrentTimeUsec(tm, &fsec, &tz); result = (TimeTzADT *) palloc(sizeof(TimeTzADT)); tm2timetz(tm, fsec, tz, result); @@ -348,18 +353,12 @@ TimeADT GetSQLLocalTime(int32 typmod) { TimeADT result; - TimestampTz ts; struct pg_tm tt, *tm = &tt; fsec_t fsec; int tz; - ts = GetCurrentTransactionStartTimestamp(); - - if (timestamp2tm(ts, &tz, tm, &fsec, NULL, NULL) != 0) - ereport(ERROR, - (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE), - errmsg("timestamp out of range"))); + GetCurrentTimeUsec(tm, &fsec, &tz); tm2time(tm, fsec, &result); AdjustTimeForTypmod(&result, typmod); diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c index dec2fad82a..91fab8cc9c 100644 --- a/src/backend/utils/adt/datetime.c +++ b/src/backend/utils/adt/datetime.c @@ -339,35 +339,80 @@ j2day(int date) /* * GetCurrentDateTime() * - * Get the transaction start time ("now()") broken down as a struct pg_tm. + * Get the transaction start time ("now()") broken down as a struct pg_tm, + * converted according to the session timezone setting. + * + * This is just a convenience wrapper for GetCurrentTimeUsec, to cover the + * case where caller doesn't need either fractional seconds or tz offset. */ void GetCurrentDateTime(struct pg_tm *tm) { - int tz; fsec_t fsec; - timestamp2tm(GetCurrentTransactionStartTimestamp(), &tz, tm, &fsec, - NULL, NULL); - /* Note: don't pass NULL tzp to timestamp2tm; affects behavior */ + GetCurrentTimeUsec(tm, &fsec, NULL); } /* * GetCurrentTimeUsec() * * Get the transaction start time ("now()") broken down as a struct pg_tm, - * including fractional seconds and timezone offset. + * including fractional seconds and timezone offset. The time is converted + * according to the session timezone setting. + * + * Callers may pass tzp = NULL if they don't need the offset, but this does + * not affect the conversion behavior (unlike timestamp2tm()). + * + * Internally, we cache the result, since this could be called many times + * in a transaction, within which now() doesn't change. */ void GetCurrentTimeUsec(struct pg_tm *tm, fsec_t *fsec, int *tzp) { - int tz; + TimestampTz cur_ts = GetCurrentTransactionStartTimestamp(); - timestamp2tm(GetCurrentTransactionStartTimestamp(), &tz, tm, fsec, - NULL, NULL); - /* Note: don't pass NULL tzp to timestamp2tm; affects behavior */ + /* + * The cache key must include both current time and current timezone. By + * representing the timezone by just a pointer, we're assuming that + * distinct timezone settings could never have the same pointer value. + * This is true by virtue of the hashtable used inside pg_tzset(); + * however, it might need another look if we ever allow entries in that + * hash to be recycled. + */ + static TimestampTz cache_ts = 0; + static pg_tz *cache_timezone = NULL; + static struct pg_tm cache_tm; + static fsec_t cache_fsec; + static int cache_tz; + + if (cur_ts != cache_ts || session_timezone != cache_timezone) + { + /* + * Make sure cache is marked invalid in case of error after partial + * update within timestamp2tm. + */ + cache_timezone = NULL; + + /* + * Perform the computation, storing results into cache. We do not + * really expect any error here, since current time surely ought to be + * within range, but check just for sanity's sake. + */ + if (timestamp2tm(cur_ts, &cache_tz, &cache_tm, &cache_fsec, + NULL, session_timezone) != 0) + ereport(ERROR, + (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE), + errmsg("timestamp out of range"))); + + /* OK, so mark the cache valid. */ + cache_ts = cur_ts; + cache_timezone = session_timezone; + } + + *tm = cache_tm; + *fsec = cache_fsec; if (tzp != NULL) - *tzp = tz; + *tzp = cache_tz; }