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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
View File

@@ -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
*/

62
src/backend/utils/adt/ruleutils.c
View File

@@ -6884,6 +6884,7 @@ isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
case T_RowExpr:
case T_CoalesceExpr:
case T_MinMaxExpr:
case T_SQLValueFunction:
case T_XmlExpr:
case T_NullIfExpr:
case T_Aggref:
@@ -7871,6 +7872,67 @@ get_rule_expr(Node *node, deparse_context *context,
}
break;
case T_SQLValueFunction:
{
SQLValueFunction *svf = (SQLValueFunction *) node;
/*
* Note: this code knows that typmod for time, timestamp, and
* timestamptz just prints as integer.
*/
switch (svf->op)
{
case SVFOP_CURRENT_DATE:
appendStringInfoString(buf, "CURRENT_DATE");
break;
case SVFOP_CURRENT_TIME:
appendStringInfoString(buf, "CURRENT_TIME");
break;
case SVFOP_CURRENT_TIME_N:
appendStringInfo(buf, "CURRENT_TIME(%d)", svf->typmod);
break;
case SVFOP_CURRENT_TIMESTAMP:
appendStringInfoString(buf, "CURRENT_TIMESTAMP");
break;
case SVFOP_CURRENT_TIMESTAMP_N:
appendStringInfo(buf, "CURRENT_TIMESTAMP(%d)",
svf->typmod);
break;
case SVFOP_LOCALTIME:
appendStringInfoString(buf, "LOCALTIME");
break;
case SVFOP_LOCALTIME_N:
appendStringInfo(buf, "LOCALTIME(%d)", svf->typmod);
break;
case SVFOP_LOCALTIMESTAMP:
appendStringInfoString(buf, "LOCALTIMESTAMP");
break;
case SVFOP_LOCALTIMESTAMP_N:
appendStringInfo(buf, "LOCALTIMESTAMP(%d)",
svf->typmod);
break;
case SVFOP_CURRENT_ROLE:
appendStringInfoString(buf, "CURRENT_ROLE");
break;
case SVFOP_CURRENT_USER:
appendStringInfoString(buf, "CURRENT_USER");
break;
case SVFOP_USER:
appendStringInfoString(buf, "USER");
break;
case SVFOP_SESSION_USER:
appendStringInfoString(buf, "SESSION_USER");
break;
case SVFOP_CURRENT_CATALOG:
appendStringInfoString(buf, "CURRENT_CATALOG");
break;
case SVFOP_CURRENT_SCHEMA:
appendStringInfoString(buf, "CURRENT_SCHEMA");
break;
}
}
break;
case T_XmlExpr:
{
XmlExpr *xexpr = (XmlExpr *) node;

60
src/backend/utils/adt/timestamp.c
View File

@@ -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()