Description: Fix failures of tests on recent postgres builds

In recent postgres builds you cannot set client_min_messages to
values higher then ERROR, if will silently set it to ERROR if so.

During some tests we would set it to fatal to hide random values
(eg. pid's of processes) from the test output. This patch will use
different tactics for hiding these values.

src/test/regress/.gitignore

@@ -9,3 +9,6 @@
 # Regression test output
 /regression.diffs
 /regression.out
+
+# Failure test side effets
+/proxy.output

src/test/regress/expected/multi_task_string_size.out

@@ -225,8 +225,12 @@ ERROR:  parameter "citus.max_task_string_size" cannot be changed without restart
 -- error message may vary between executions
 -- hiding warning and error message
 -- no output means the query has failed
-SET client_min_messages to FATAL;
+SET client_min_messages to ERROR;
+SELECT raise_failed_execution('
 SELECT u.* FROM wide_table u JOIN wide_table v ON (u.long_column_002 = v.long_column_003);
+');
+ERROR:  Task failed to execute
+CONTEXT:  PL/pgSQL function raise_failed_execution(text) line 6 at RAISE
 -- following will succeed since it fetches few columns
 SELECT u.long_column_001, u.long_column_002, u.long_column_003 FROM wide_table u JOIN wide_table v ON (u.long_column_002 = v.long_column_003);
  long_column_001 | long_column_002 | long_column_003 

src/test/regress/expected/multi_test_helpers.out

@@ -84,3 +84,13 @@ $desc_views$
  
 (1 row)
 
+-- Create a function to make sure that queries returning the same result
+CREATE FUNCTION raise_failed_execution(query text) RETURNS void AS $$
+BEGIN
+	EXECUTE query;
+	EXCEPTION WHEN OTHERS THEN
+	IF SQLERRM LIKE 'failed to execute task%' THEN
+		RAISE 'Task failed to execute';
+	END IF;
+END;
+$$LANGUAGE plpgsql;

src/test/regress/sql/multi_task_string_size.sql

@@ -220,9 +220,11 @@ SET citus.max_task_string_size TO 20000;
 -- error message may vary between executions
 -- hiding warning and error message
 -- no output means the query has failed
-SET client_min_messages to FATAL;
+SET client_min_messages to ERROR;
 
+SELECT raise_failed_execution('
 SELECT u.* FROM wide_table u JOIN wide_table v ON (u.long_column_002 = v.long_column_003);
+');
 
 -- following will succeed since it fetches few columns
 SELECT u.long_column_001, u.long_column_002, u.long_column_003 FROM wide_table u JOIN wide_table v ON (u.long_column_002 = v.long_column_003);

src/test/regress/sql/multi_test_helpers.sql

@@ -81,3 +81,14 @@ WHERE cc.constraint_schema = ccu.constraint_schema AND
 ORDER BY cc.constraint_name ASC;
 $desc_views$
 );
+
+-- Create a function to make sure that queries returning the same result
+CREATE FUNCTION raise_failed_execution(query text) RETURNS void AS $$
+BEGIN
+	EXECUTE query;
+	EXCEPTION WHEN OTHERS THEN
+	IF SQLERRM LIKE 'failed to execute task%' THEN
+		RAISE 'Task failed to execute';
+	END IF;
+END;
+$$LANGUAGE plpgsql;