/*
* pg_sleep - delay for N seconds
*/
Datum
pg_sleep(PG_FUNCTION_ARGS)
{
float8 secs = PG_GETARG_FLOAT8(0);
float8 endtime;
/*
* We sleep using WaitLatch, to ensure that we'll wake up promptly if an
* important signal (such as SIGALRM or SIGINT) arrives. Because
* WaitLatch's upper limit of delay is INT_MAX milliseconds, and the user
* might ask for more than that, we sleep for at most 10 minutes and then
* loop.
*
* By computing the intended stop time initially, we avoid accumulation of
* extra delay across multiple sleeps. This also ensures we won't delay
* less than the specified time when WaitLatch is terminated early by a
* non-query-canceling signal such as SIGHUP.
*/
#ifdef HAVE_INT64_TIMESTAMP
#define GetNowFloat() ((float8) GetCurrentTimestamp() / 1000000.0)
#else
#define GetNowFloat() GetCurrentTimestamp()
#endif
endtime = GetNowFloat() + secs;
for (;;)
{
float8 delay;
long delay_ms;
CHECK_FOR_INTERRUPTS();
delay = endtime - GetNowFloat();
if (delay >= 600.0)
delay_ms = 600000;
else if (delay > 0.0)
delay_ms = (long) ceil(delay * 1000.0);
else
break;
(void) WaitLatch(MyLatch,
WL_LATCH_SET | WL_TIMEOUT,
delay_ms,
WAIT_EVENT_PG_SLEEP);
ResetLatch(MyLatch);
}
PG_RETURN_VOID();
}
/*
* pg_sleep - delay for N seconds
*/
Datum
pg_sleep(PG_FUNCTION_ARGS)
{
float8 secs = PG_GETARG_FLOAT8(0);
float8 endtime;
/*
* We break the requested sleep into segments of no more than 1 second, to
* put an upper bound on how long it will take us to respond to a cancel
* or die interrupt. (Note that pg_usleep is interruptible by signals on
* some platforms but not others.) Also, this method avoids exposing
* pg_usleep's upper bound on allowed delays.
*
* By computing the intended stop time initially, we avoid accumulation of
* extra delay across multiple sleeps. This also ensures we won't delay
* less than the specified time if pg_usleep is interrupted by other
* signals such as SIGHUP.
*/
#ifdef HAVE_INT64_TIMESTAMP
#define GetNowFloat() ((float8) GetCurrentTimestamp() / 1000000.0)
#else
#define GetNowFloat() GetCurrentTimestamp()
#endif
endtime = GetNowFloat() + secs;
for (;;)
{
float8 delay;
CHECK_FOR_INTERRUPTS();
delay = endtime - GetNowFloat();
if (delay >= 1.0)
pg_usleep(1000000L);
else if (delay > 0.0)
pg_usleep((long) ceil(delay * 1000000.0));
else
break;
}
PG_RETURN_VOID();
}
