Add skip-empty-xacts option to test_decoding for use in the regression tests.

The regression tests for contrib/test_decoding regularly failed on
postgres instances that were very slow. Either because the hardware
itself was slow or because very expensive debugging options like
CLOBBER_CACHE_ALWAYS were used.

The reason they failed was just that some additional transactions were
decoded. Analyze and vacuum, triggered by autovac.

To fix just add a option to test_decoding to only display transactions
in which a change was actually displayed. That's not pretty because it
removes information from the tests; but better than constantly failing
tests in very likely harmless ways.

Backpatch to 9.4 where logical decoding was introduced.

Discussion: 20140629142511.GA26930@awork2.anarazel.de

1 files changed, 3 insertions, 3 deletions

diff --git a/contrib/test_decoding/sql/permissions.sql b/contrib/test_decoding/sql/permissions.sql
index 39d70b56b00..8680c55771d 100644
--- a/contrib/test_decoding/sql/permissions.sql
+++ b/contrib/test_decoding/sql/permissions.sql
@@ -11,7 +11,7 @@ CREATE TABLE lr_test(data text);
 SET ROLE lr_superuser;
 SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
 INSERT INTO lr_test VALUES('lr_superuser_init');
-SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0');
+SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
 SELECT pg_drop_replication_slot('regression_slot');
 RESET ROLE;
 
@@ -19,7 +19,7 @@ RESET ROLE;
 SET ROLE lr_replication;
 SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
 INSERT INTO lr_test VALUES('lr_superuser_init');
-SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0');
+SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
 SELECT pg_drop_replication_slot('regression_slot');
 RESET ROLE;
 
@@ -27,7 +27,7 @@ RESET ROLE;
 SET ROLE lr_normal;
 SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
 INSERT INTO lr_test VALUES('lr_superuser_init');
-SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0');
+SELECT data FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');
 SELECT pg_drop_replication_slot('regression_slot');
 RESET ROLE;