Function check_log_duration

src/backend/tcop/postgres.c:3190–3245

* check_log_duration * Determine whether current command's duration should be logged * We also check if this statement in this transaction must be logged * (regardless of its duration). * * Returns: * 0 if no logging is needed * 1 if just the duration should be logged * 2 if duration and query details should be logged * * If logging is needed, the duration in msec is formatted into

 * essentially prevents 2 from being returned).
 */
int
check_log_duration(char *msec_str, bool was_logged)
{
	if (log_duration || log_min_duration_sample >= 0 ||
		log_min_duration_statement >= 0 || xact_is_sampled)
	{
		long		secs;
		int			usecs;
		int			msecs;
		bool		exceeded_duration;
		bool		exceeded_sample_duration;
		bool		in_sample = false;

		TimestampDifference(GetCurrentStatementStartTimestamp(),
							GetCurrentTimestamp(),
							&secs, &usecs);
		msecs = usecs / 1000;

		/*
		 * This odd-looking test for log_min_duration_* being exceeded is
		 * designed to avoid integer overflow with very long durations: don't
		 * compute secs * 1000 until we've verified it will fit in int.
		 */
		exceeded_duration = (log_min_duration_statement == 0 ||
							 (log_min_duration_statement > 0 &&
							  (secs > log_min_duration_statement / 1000 ||
							   secs * 1000 + msecs >= log_min_duration_statement)));

		exceeded_sample_duration = (log_min_duration_sample == 0 ||
									(log_min_duration_sample > 0 &&
									 (secs > log_min_duration_sample / 1000 ||
									  secs * 1000 + msecs >= log_min_duration_sample)));

		/*
		 * Do not log if log_statement_sample_rate = 0. Log a sample if
		 * log_statement_sample_rate <= 1 and avoid unnecessary random() call
		 * if log_statement_sample_rate = 1.
		 */
		if (exceeded_sample_duration)
			in_sample = log_statement_sample_rate != 0 &&
				(log_statement_sample_rate == 1 ||
				 random() <= log_statement_sample_rate * MAX_RANDOM_VALUE);

		if (exceeded_duration || in_sample || log_duration || xact_is_sampled)
		{
			snprintf(msec_str, 32, "%ld.%03d",
					 secs * 1000 + msecs, usecs % 1000);
			if ((exceeded_duration || in_sample || xact_is_sampled) && !was_logged)
				return 2;
			else
				return 1;
		}
	}

	return 0;
}

/*