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Improve parsetree representation of special functions such as CURRENT_DATE.

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We implement a dozen or so parameterless functions that the SQL standard
defines special syntax for.  Up to now, that was done by converting them
into more or less ad-hoc constructs such as "'now'::text::date".  That's
messy for multiple reasons: it exposes what should be implementation
details to users, and performance is worse than it needs to be in several
cases.  To improve matters, invent a new expression node type
SQLValueFunction that can represent any of these parameterless functions.

Bump catversion because this changes stored parsetrees for rules.

Discussion: <30058.1463091294@sss.pgh.pa.us>
This commit is contained in:
Tom Lane
2016-08-16 20:33:01 -04:00
parent 4bc4cfe3bd
commit 0bb51aa967
24 changed files with 626 additions and 168 deletions
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60
src/backend/utils/adt/timestamp.c
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@ -72,13 +72,13 @@ static Timestamp dt2local(Timestamp dt, int timezone);
static void AdjustTimestampForTypmod(Timestamp *time, int32 typmod);
static void AdjustIntervalForTypmod(Interval *interval, int32 typmod);
static TimestampTz timestamp2timestamptz(Timestamp timestamp);
static Timestamp timestamptz2timestamp(TimestampTz timestamp);
/* common code for timestamptypmodin and timestamptztypmodin */
static int32
anytimestamp_typmodin(bool istz, ArrayType *ta)
{
int32 typmod;
int32 *tl;
int n;
@ -93,22 +93,27 @@ anytimestamp_typmodin(bool istz, ArrayType *ta)
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid type modifier")));
if (*tl < 0)
return anytimestamp_typmod_check(istz, tl[0]);
}
/* exported so parse_expr.c can use it */
int32
anytimestamp_typmod_check(bool istz, int32 typmod)
{
if (typmod < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("TIMESTAMP(%d)%s precision must not be negative",
*tl, (istz ? " WITH TIME ZONE" : ""))));
if (*tl > MAX_TIMESTAMP_PRECISION)
typmod, (istz ? " WITH TIME ZONE" : ""))));
if (typmod > MAX_TIMESTAMP_PRECISION)
{
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("TIMESTAMP(%d)%s precision reduced to maximum allowed, %d",
*tl, (istz ? " WITH TIME ZONE" : ""),
typmod, (istz ? " WITH TIME ZONE" : ""),
MAX_TIMESTAMP_PRECISION)));
typmod = MAX_TIMESTAMP_PRECISION;
}
else
typmod = *tl;
return typmod;
}
@ -336,6 +341,10 @@ timestamp_scale(PG_FUNCTION_ARGS)
PG_RETURN_TIMESTAMP(result);
}
/*
* AdjustTimestampForTypmod --- round off a timestamp to suit given typmod
* Works for either timestamp or timestamptz.
*/
static void
AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
{
@ -1686,6 +1695,34 @@ IntegerTimestampToTimestampTz(int64 timestamp)
}
#endif
/*
* GetSQLCurrentTimestamp -- implements CURRENT_TIMESTAMP, CURRENT_TIMESTAMP(n)
*/
TimestampTz
GetSQLCurrentTimestamp(int32 typmod)
{
TimestampTz ts;
ts = GetCurrentTransactionStartTimestamp();
if (typmod >= 0)
AdjustTimestampForTypmod(&ts, typmod);
return ts;
}
/*
* GetSQLLocalTimestamp -- implements LOCALTIMESTAMP, LOCALTIMESTAMP(n)
*/
Timestamp
GetSQLLocalTimestamp(int32 typmod)
{
Timestamp ts;
ts = timestamptz2timestamp(GetCurrentTransactionStartTimestamp());
if (typmod >= 0)
AdjustTimestampForTypmod(&ts, typmod);
return ts;
}
/*
* TimestampDifference -- convert the difference between two timestamps
* into integer seconds and microseconds
@ -5415,6 +5452,13 @@ Datum
timestamptz_timestamp(PG_FUNCTION_ARGS)
{
TimestampTz timestamp = PG_GETARG_TIMESTAMPTZ(0);
PG_RETURN_TIMESTAMP(timestamptz2timestamp(timestamp));
}
static Timestamp
timestamptz2timestamp(TimestampTz timestamp)
{
Timestamp result;
struct pg_tm tt,
*tm = &tt;
@ -5434,7 +5478,7 @@ timestamptz_timestamp(PG_FUNCTION_ARGS)
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range")));
}
PG_RETURN_TIMESTAMP(result);
return result;
}
/* timestamptz_zone()