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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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93
src/backend/utils/adt/date.c
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@@ -21,6 +21,7 @@
#include <time.h>
#include "access/hash.h"
#include "access/xact.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
#include "parser/scansup.h"
@@ -51,7 +52,6 @@ static void AdjustTimeForTypmod(TimeADT *time, int32 typmod);
static int32
anytime_typmodin(bool istz, ArrayType *ta)
{
int32 typmod;
int32 *tl;
int n;
@@ -66,22 +66,27 @@ anytime_typmodin(bool istz, ArrayType *ta)
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid type modifier")));
if (*tl < 0)
return anytime_typmod_check(istz, tl[0]);
}
/* exported so parse_expr.c can use it */
int32
anytime_typmod_check(bool istz, int32 typmod)
{
if (typmod < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("TIME(%d)%s precision must not be negative",
*tl, (istz ? " WITH TIME ZONE" : ""))));
if (*tl > MAX_TIME_PRECISION)
typmod, (istz ? " WITH TIME ZONE" : ""))));
if (typmod > MAX_TIME_PRECISION)
{
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("TIME(%d)%s precision reduced to maximum allowed, %d",
*tl, (istz ? " WITH TIME ZONE" : ""),
typmod, (istz ? " WITH TIME ZONE" : ""),
MAX_TIME_PRECISION)));
typmod = MAX_TIME_PRECISION;
}
else
typmod = *tl;
return typmod;
}
@@ -298,6 +303,80 @@ EncodeSpecialDate(DateADT dt, char *str)
}
/*
* GetSQLCurrentDate -- implements CURRENT_DATE
*/
DateADT
GetSQLCurrentDate(void)
{
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")));
return date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - POSTGRES_EPOCH_JDATE;
}
/*
* GetSQLCurrentTime -- implements CURRENT_TIME, CURRENT_TIME(n)
*/
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")));
result = (TimeTzADT *) palloc(sizeof(TimeTzADT));
tm2timetz(tm, fsec, tz, result);
AdjustTimeForTypmod(&(result->time), typmod);
return result;
}
/*
* GetSQLLocalTime -- implements LOCALTIME, LOCALTIME(n)
*/
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")));
tm2time(tm, fsec, &result);
AdjustTimeForTypmod(&result, typmod);
return result;
}
/*
* Comparison functions for dates
*/