Function pgstat_init_function_usage

src/backend/postmaster/pgstat.c:1926–1969

* Initialize function call usage data. * Called by the executor before invoking a function. */

 * Called by the executor before invoking a function.
 */
void
pgstat_init_function_usage(FunctionCallInfo fcinfo,
						   PgStat_FunctionCallUsage *fcu)
{
	PgStat_BackendFunctionEntry *htabent;
	bool		found;

	if (pgstat_track_functions <= fcinfo->flinfo->fn_stats)
	{
		/* stats not wanted */
		fcu->fs = NULL;
		return;
	}

	if (!pgStatFunctions)
	{
		/* First time through - initialize function stat table */
		HASHCTL		hash_ctl;

		hash_ctl.keysize = sizeof(Oid);
		hash_ctl.entrysize = sizeof(PgStat_BackendFunctionEntry);
		pgStatFunctions = hash_create("Function stat entries",
									  PGSTAT_FUNCTION_HASH_SIZE,
									  &hash_ctl,
									  HASH_ELEM | HASH_BLOBS);
	}

	/* Get the stats entry for this function, create if necessary */
	htabent = hash_search(pgStatFunctions, &fcinfo->flinfo->fn_oid,
						  HASH_ENTER, &found);
	if (!found)
		MemSet(&htabent->f_counts, 0, sizeof(PgStat_FunctionCounts));

	fcu->fs = &htabent->f_counts;

	/* save stats for this function, later used to compensate for recursion */
	fcu->save_f_total_time = htabent->f_counts.f_total_time;

	/* save current backend-wide total time */
	fcu->save_total = total_func_time;

	/* get clock time as of function start */
	INSTR_TIME_SET_CURRENT(fcu->f_start);
}

/*
 * find_funcstat_entry - find any existing PgStat_BackendFunctionEntry entry