postgres/src/include/utils/timestamp.h
Tom Lane 171c457cd0 Fix and simplify some usages of TimestampDifference().
Introduce TimestampDifferenceMilliseconds() to simplify callers
that would rather have the difference in milliseconds, instead of
the select()-oriented seconds-and-microseconds format.  This gets
rid of at least one integer division per call, and it eliminates
some apparently-easy-to-mess-up arithmetic.

Two of these call sites were in fact wrong:

* pg_prewarm's autoprewarm_main() forgot to multiply the seconds
by 1000, thus ending up with a delay 1000X shorter than intended.
That doesn't quite make it a busy-wait, but close.

* postgres_fdw's pgfdw_get_cleanup_result() thought it needed to compute
microseconds not milliseconds, thus ending up with a delay 1000X longer
than intended.  Somebody along the way had noticed this problem but
misdiagnosed the cause, and imposed an ad-hoc 60-second limit rather
than fixing the units.  This was relatively harmless in context, because
we don't care that much about exactly how long this delay is; still,
it's wrong.

There are a few more callers of TimestampDifference() that don't
have a direct need for seconds-and-microseconds, but can't use
TimestampDifferenceMilliseconds() either because they do need
microsecond precision or because they might possibly deal with
intervals long enough to overflow 32-bit milliseconds.  It might be
worth inventing another API to improve that, but that seems outside
the scope of this patch; so those callers are untouched here.

Given the fact that we are fixing some bugs, and the likelihood
that future patches might want to back-patch code that uses this
new API, back-patch to all supported branches.

Alexey Kondratov and Tom Lane

Discussion: https://postgr.es/m/3b1c053a21c07c1ed5e00be3b2b855ef@postgrespro.ru
2020-11-10 22:51:55 -05:00

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C

/*-------------------------------------------------------------------------
*
* timestamp.h
* Definitions for the SQL "timestamp" and "interval" types.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/timestamp.h
*
*-------------------------------------------------------------------------
*/
#ifndef TIMESTAMP_H
#define TIMESTAMP_H
#include "datatype/timestamp.h"
#include "fmgr.h"
#include "pgtime.h"
/*
* Macros for fmgr-callable functions.
*
* For Timestamp, we make use of the same support routines as for int64.
* Therefore Timestamp is pass-by-reference if and only if int64 is!
*/
#define DatumGetTimestamp(X) ((Timestamp) DatumGetInt64(X))
#define DatumGetTimestampTz(X) ((TimestampTz) DatumGetInt64(X))
#define DatumGetIntervalP(X) ((Interval *) DatumGetPointer(X))
#define TimestampGetDatum(X) Int64GetDatum(X)
#define TimestampTzGetDatum(X) Int64GetDatum(X)
#define IntervalPGetDatum(X) PointerGetDatum(X)
#define PG_GETARG_TIMESTAMP(n) DatumGetTimestamp(PG_GETARG_DATUM(n))
#define PG_GETARG_TIMESTAMPTZ(n) DatumGetTimestampTz(PG_GETARG_DATUM(n))
#define PG_GETARG_INTERVAL_P(n) DatumGetIntervalP(PG_GETARG_DATUM(n))
#define PG_RETURN_TIMESTAMP(x) return TimestampGetDatum(x)
#define PG_RETURN_TIMESTAMPTZ(x) return TimestampTzGetDatum(x)
#define PG_RETURN_INTERVAL_P(x) return IntervalPGetDatum(x)
#define TIMESTAMP_MASK(b) (1 << (b))
#define INTERVAL_MASK(b) (1 << (b))
/* Macros to handle packing and unpacking the typmod field for intervals */
#define INTERVAL_FULL_RANGE (0x7FFF)
#define INTERVAL_RANGE_MASK (0x7FFF)
#define INTERVAL_FULL_PRECISION (0xFFFF)
#define INTERVAL_PRECISION_MASK (0xFFFF)
#define INTERVAL_TYPMOD(p,r) ((((r) & INTERVAL_RANGE_MASK) << 16) | ((p) & INTERVAL_PRECISION_MASK))
#define INTERVAL_PRECISION(t) ((t) & INTERVAL_PRECISION_MASK)
#define INTERVAL_RANGE(t) (((t) >> 16) & INTERVAL_RANGE_MASK)
#define TimestampTzPlusMilliseconds(tz,ms) ((tz) + ((ms) * (int64) 1000))
/* Set at postmaster start */
extern TimestampTz PgStartTime;
/* Set at configuration reload */
extern TimestampTz PgReloadTime;
/* Internal routines (not fmgr-callable) */
extern int32 anytimestamp_typmod_check(bool istz, int32 typmod);
extern TimestampTz GetCurrentTimestamp(void);
extern TimestampTz GetSQLCurrentTimestamp(int32 typmod);
extern Timestamp GetSQLLocalTimestamp(int32 typmod);
extern void TimestampDifference(TimestampTz start_time, TimestampTz stop_time,
long *secs, int *microsecs);
extern long TimestampDifferenceMilliseconds(TimestampTz start_time,
TimestampTz stop_time);
extern bool TimestampDifferenceExceeds(TimestampTz start_time,
TimestampTz stop_time,
int msec);
extern TimestampTz time_t_to_timestamptz(pg_time_t tm);
extern pg_time_t timestamptz_to_time_t(TimestampTz t);
extern const char *timestamptz_to_str(TimestampTz t);
extern int tm2timestamp(struct pg_tm *tm, fsec_t fsec, int *tzp, Timestamp *dt);
extern int timestamp2tm(Timestamp dt, int *tzp, struct pg_tm *tm,
fsec_t *fsec, const char **tzn, pg_tz *attimezone);
extern void dt2time(Timestamp dt, int *hour, int *min, int *sec, fsec_t *fsec);
extern int interval2tm(Interval span, struct pg_tm *tm, fsec_t *fsec);
extern int tm2interval(struct pg_tm *tm, fsec_t fsec, Interval *span);
extern Timestamp SetEpochTimestamp(void);
extern void GetEpochTime(struct pg_tm *tm);
extern int timestamp_cmp_internal(Timestamp dt1, Timestamp dt2);
/* timestamp comparison works for timestamptz also */
#define timestamptz_cmp_internal(dt1,dt2) timestamp_cmp_internal(dt1, dt2)
extern int isoweek2j(int year, int week);
extern void isoweek2date(int woy, int *year, int *mon, int *mday);
extern void isoweekdate2date(int isoweek, int wday, int *year, int *mon, int *mday);
extern int date2isoweek(int year, int mon, int mday);
extern int date2isoyear(int year, int mon, int mday);
extern int date2isoyearday(int year, int mon, int mday);
extern bool TimestampTimestampTzRequiresRewrite(void);
#endif /* TIMESTAMP_H */