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Break out xxx2yyy_opt_overflow APIs for more datetime conversions.

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Previous commits invented timestamp2timestamptz_opt_overflow,
date2timestamp_opt_overflow, and date2timestamptz_opt_overflow
functions to perform non-error-throwing conversions between
datetime types.  This patch completes the set by adding
timestamp2date_opt_overflow, timestamptz2date_opt_overflow,
and timestamptz2timestamp_opt_overflow.

In addition, adjust timestamp2timestamptz_opt_overflow so that it
doesn't throw error if timestamp2tm fails, but treats that as an
overflow case.  The situation probably can't arise except with an
invalid timestamp value, and I can't think of a way that that would
happen except data corruption.  However, it's pretty silly to have a
function whose entire reason for existence is to not throw errors for
out-of-range inputs nonetheless throw an error for out-of-range input.

The new APIs are not used in this patch, but will be needed in
upcoming btree_gin changes.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Arseniy Mukhin <arseniy.mukhin.dev@gmail.com>
Discussion: https://postgr.es/m/262624.1738460652@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2025-07-03 16:17:08 -04:00
parent a10f21e6ce
commit 0059bbe1ec
4 changed files with 157 additions and 17 deletions
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83
src/backend/utils/adt/timestamp.c
View File

@ -6477,7 +6477,7 @@ timestamp2timestamptz_opt_overflow(Timestamp timestamp, int *overflow)
if (TIMESTAMP_NOT_FINITE(timestamp))
return timestamp;
/* We don't expect this to fail, but check it pro forma */
/* timestamp2tm should not fail on valid timestamps, but cope */
if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL, NULL) == 0)
{
tz = DetermineTimeZoneOffset(tm, session_timezone);
@ -6485,23 +6485,22 @@ timestamp2timestamptz_opt_overflow(Timestamp timestamp, int *overflow)
result = dt2local(timestamp, -tz);
if (IS_VALID_TIMESTAMP(result))
{
return result;
}
else if (overflow)
}
if (overflow)
{
if (timestamp < 0)
{
if (result < MIN_TIMESTAMP)
{
*overflow = -1;
TIMESTAMP_NOBEGIN(result);
}
else
{
*overflow = 1;
TIMESTAMP_NOEND(result);
}
return result;
*overflow = -1;
TIMESTAMP_NOBEGIN(result);
}
else
{
*overflow = 1;
TIMESTAMP_NOEND(result);
}
return result;
}
ereport(ERROR,
@ -6531,8 +6530,27 @@ timestamptz_timestamp(PG_FUNCTION_ARGS)
PG_RETURN_TIMESTAMP(timestamptz2timestamp(timestamp));
}
/*
* Convert timestamptz to timestamp, throwing error for overflow.
*/
static Timestamp
timestamptz2timestamp(TimestampTz timestamp)
{
return timestamptz2timestamp_opt_overflow(timestamp, NULL);
}
/*
* Convert timestamp with time zone to timestamp.
*
* On successful conversion, *overflow is set to zero if it's not NULL.
*
* If the timestamptz is finite but out of the valid range for timestamp, then:
* if overflow is NULL, we throw an out-of-range error.
* if overflow is not NULL, we store +1 or -1 there to indicate the sign
* of the overflow, and return the appropriate timestamp infinity.
*/
Timestamp
timestamptz2timestamp_opt_overflow(TimestampTz timestamp, int *overflow)
{
Timestamp result;
struct pg_tm tt,
@ -6540,18 +6558,53 @@ timestamptz2timestamp(TimestampTz timestamp)
fsec_t fsec;
int tz;
if (overflow)
*overflow = 0;
if (TIMESTAMP_NOT_FINITE(timestamp))
result = timestamp;
else
{
if (timestamp2tm(timestamp, &tz, tm, &fsec, NULL, NULL) != 0)
{
if (overflow)
{
if (timestamp < 0)
{
*overflow = -1;
TIMESTAMP_NOBEGIN(result);
}
else
{
*overflow = 1;
TIMESTAMP_NOEND(result);
}
return result;
}
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range")));
}
if (tm2timestamp(tm, fsec, NULL, &result) != 0)
{
if (overflow)
{
if (timestamp < 0)
{
*overflow = -1;
TIMESTAMP_NOBEGIN(result);
}
else
{
*overflow = 1;
TIMESTAMP_NOEND(result);
}
return result;
}
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range")));
}
}
return result;
}