Fix tests for 9.6

Author: ildus

expected/queries.out

@@ -1,17 +1,20 @@
 CREATE EXTENSION pg_wait_sampling;
-SELECT SUM(0) FROM pg_wait_sampling_current;
+WITH t as (SELECT sum(0) FROM pg_wait_sampling_current)
+	SELECT sum(0) FROM generate_series(1, 2), t;
  sum 
 -----
    0
 (1 row)
 
-SELECT SUM(0) FROM pg_wait_sampling_history;
+WITH t as (SELECT sum(0) FROM pg_wait_sampling_history)
+	SELECT sum(0) FROM generate_series(1, 2), t;
  sum 
 -----
    0
 (1 row)
 
-SELECT SUM(0) FROM pg_wait_sampling_profile;
+WITH t as (SELECT sum(0) FROM pg_wait_sampling_profile)
+	SELECT sum(0) FROM generate_series(1, 2), t;
  sum 
 -----
    0

pg_wait_sampling.c

@@ -418,7 +418,7 @@ pg_wait_sampling_get_current(PG_FUNCTION_ARGS)
 			{
 				PGPROC *proc = &ProcGlobal->allProcs[i];
 
-				if (proc != NULL && proc->pid != 0)
+				if (proc != NULL && proc->pid != 0 && proc->wait_event_info)
 				{
 					params->items[j].pid = proc->pid;
 					params->items[j].wait_event_info = proc->wait_event_info;

sql/queries.sql

@@ -1,8 +1,13 @@
 CREATE EXTENSION pg_wait_sampling;
 
-SELECT SUM(0) FROM pg_wait_sampling_current;
-SELECT SUM(0) FROM pg_wait_sampling_history;
-SELECT SUM(0) FROM pg_wait_sampling_profile;
+WITH t as (SELECT sum(0) FROM pg_wait_sampling_current)
+	SELECT sum(0) FROM generate_series(1, 2), t;
+
+WITH t as (SELECT sum(0) FROM pg_wait_sampling_history)
+	SELECT sum(0) FROM generate_series(1, 2), t;
+
+WITH t as (SELECT sum(0) FROM pg_wait_sampling_profile)
+	SELECT sum(0) FROM generate_series(1, 2), t;
 
 SELECT pg_wait_sampling_reset_profile();