Try out single node follower cluster

src/test/regress/expected/follower_single_node.out

@@ -0,0 +1,288 @@
+\c - - - :master_port
+SET citus.shard_count TO 4;
+SET citus.shard_replication_factor TO 1;
+SET citus.next_shard_id TO 93630500;
+SELECT 1 FROM master_add_node('localhost', :master_port, groupid => 0);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+SELECT 1 FROM master_set_node_property('localhost', :master_port, 'shouldhaveshards', true);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+CREATE TABLE test(x int, y int);
+SELECT create_distributed_table('test','x');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE TABLE ref(a int, b int);
+SELECT create_reference_table('ref');
+ create_reference_table
+---------------------------------------------------------------------
+
+(1 row)
+
+CREATE TABLE local(c int, d int);
+INSERT INTO test VALUES (1, 2), (3, 4), (5, 6), (2, 7), (4, 5);
+INSERT INTO ref VALUES (1, 2), (5, 6), (7, 8);
+INSERT INTO local VALUES (1, 2), (3, 4), (7, 8);
+-- connect to the follower and check that a simple select query works, the follower
+-- is still in the default cluster and will send queries to the primary nodes
+\c - - - :follower_master_port
+SELECT * FROM test WHERE x = 1;
+ x | y
+---------------------------------------------------------------------
+ 1 | 2
+(1 row)
+
+SELECT count(*) FROM test;
+ count
+---------------------------------------------------------------------
+     5
+(1 row)
+
+SELECT * FROM test ORDER BY x;
+ x | y
+---------------------------------------------------------------------
+ 1 | 2
+ 2 | 7
+ 3 | 4
+ 4 | 5
+ 5 | 6
+(5 rows)
+
+SELECT count(*) FROM ref;
+ count
+---------------------------------------------------------------------
+     3
+(1 row)
+
+SELECT * FROM ref ORDER BY a;
+ a | b
+---------------------------------------------------------------------
+ 1 | 2
+ 5 | 6
+ 7 | 8
+(3 rows)
+
+SELECT * FROM test, ref WHERE x = a ORDER BY x;
+ x | y | a | b
+---------------------------------------------------------------------
+ 1 | 2 | 1 | 2
+ 5 | 6 | 5 | 6
+(2 rows)
+
+SELECT count(*) FROM local;
+ count
+---------------------------------------------------------------------
+     3
+(1 row)
+
+SELECT * FROM local ORDER BY c;
+ c | d
+---------------------------------------------------------------------
+ 1 | 2
+ 3 | 4
+ 7 | 8
+(3 rows)
+
+SELECT * FROM ref, local WHERE a = c ORDER BY a;
+ a | b | c | d
+---------------------------------------------------------------------
+ 1 | 2 | 1 | 2
+ 7 | 8 | 7 | 8
+(2 rows)
+
+-- Check repartion joins are support
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+ERROR:  floating-point exception
+DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+SET citus.enable_repartition_joins TO ON;
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+ERROR:  floating-point exception
+DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+RESET citus.enable_repartition_joins;
+-- Confirm that dummy placements work
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+                           QUERY PLAN
+---------------------------------------------------------------------
+ Custom Scan (Citus Adaptive)  (cost=0.00..0.00 rows=0 width=0)
+   Task Count: 1
+   Tasks Shown: All
+   ->  Task
+         Node: host=localhost port=xxxxx dbname=regression
+         ->  HashAggregate  (cost=0.02..0.04 rows=2 width=16)
+               Hash Key: NULL::integer
+               Hash Key: NULL::integer
+               ->  Result  (cost=0.00..0.01 rows=1 width=8)
+                     One-Time Filter: (false AND false)
+(10 rows)
+
+-- Confirm that they work with round-robin task assignment policy
+SET citus.task_assignment_policy TO 'round-robin';
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+                           QUERY PLAN
+---------------------------------------------------------------------
+ Custom Scan (Citus Adaptive)  (cost=0.00..0.00 rows=0 width=0)
+   Task Count: 1
+   Tasks Shown: All
+   ->  Task
+         Node: host=localhost port=xxxxx dbname=regression
+         ->  HashAggregate  (cost=0.02..0.04 rows=2 width=16)
+               Hash Key: NULL::integer
+               Hash Key: NULL::integer
+               ->  Result  (cost=0.00..0.01 rows=1 width=8)
+                     One-Time Filter: (false AND false)
+(10 rows)
+
+-- now, connect to the follower but tell it to use secondary nodes. There are no
+-- secondary nodes so this should fail.
+-- (this is :follower_master_port but substitution doesn't work here)
+\c "port=9070 dbname=regression options='-c\ citus.use_secondary_nodes=always'"
+SELECT * FROM test WHERE x = 1;
+ERROR:  node group 0 does not have a secondary node
+-- add the the follower as secondary nodes and try again, the SELECT statement
+-- should work this time
+\c - - - :master_port
+SELECT 1 FROM master_add_node('localhost', :follower_master_port, groupid => 0, noderole => 'secondary');
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+SELECT 1 FROM master_set_node_property('localhost', :master_port, 'shouldhaveshards', true);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+\c "port=9070 dbname=regression options='-c\ citus.use_secondary_nodes=always'"
+SELECT * FROM test WHERE x = 1;
+ x | y
+---------------------------------------------------------------------
+ 1 | 2
+(1 row)
+
+SELECT count(*) FROM test;
+ count
+---------------------------------------------------------------------
+     5
+(1 row)
+
+SELECT * FROM test ORDER BY x;
+ x | y
+---------------------------------------------------------------------
+ 1 | 2
+ 2 | 7
+ 3 | 4
+ 4 | 5
+ 5 | 6
+(5 rows)
+
+SELECT count(*) FROM ref;
+ count
+---------------------------------------------------------------------
+     3
+(1 row)
+
+SELECT * FROM ref ORDER BY a;
+ a | b
+---------------------------------------------------------------------
+ 1 | 2
+ 5 | 6
+ 7 | 8
+(3 rows)
+
+SELECT * FROM test, ref WHERE x = a ORDER BY x;
+ x | y | a | b
+---------------------------------------------------------------------
+ 1 | 2 | 1 | 2
+ 5 | 6 | 5 | 6
+(2 rows)
+
+SELECT count(*) FROM local;
+ count
+---------------------------------------------------------------------
+     3
+(1 row)
+
+SELECT * FROM local ORDER BY c;
+ c | d
+---------------------------------------------------------------------
+ 1 | 2
+ 3 | 4
+ 7 | 8
+(3 rows)
+
+SELECT * FROM ref, local WHERE a = c ORDER BY a;
+ a | b | c | d
+---------------------------------------------------------------------
+ 1 | 2 | 1 | 2
+ 7 | 8 | 7 | 8
+(2 rows)
+
+-- Check repartion joins are support
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+ERROR:  floating-point exception
+DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+SET citus.enable_repartition_joins TO ON;
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+ERROR:  floating-point exception
+DETAIL:  An invalid floating-point operation was signaled. This probably means an out-of-range result or an invalid operation, such as division by zero.
+RESET citus.enable_repartition_joins;
+-- Confirm that dummy placements work
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+                           QUERY PLAN
+---------------------------------------------------------------------
+ Custom Scan (Citus Adaptive)  (cost=0.00..0.00 rows=0 width=0)
+   Task Count: 1
+   Tasks Shown: All
+   ->  Task
+         Node: host=localhost port=xxxxx dbname=regression
+         ->  HashAggregate  (cost=0.02..0.04 rows=2 width=16)
+               Hash Key: NULL::integer
+               Hash Key: NULL::integer
+               ->  Result  (cost=0.00..0.01 rows=1 width=8)
+                     One-Time Filter: (false AND false)
+(10 rows)
+
+-- Confirm that they work with round-robin task assignment policy
+SET citus.task_assignment_policy TO 'round-robin';
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+                           QUERY PLAN
+---------------------------------------------------------------------
+ Custom Scan (Citus Adaptive)  (cost=0.00..0.00 rows=0 width=0)
+   Task Count: 1
+   Tasks Shown: All
+   ->  Task
+         Node: host=localhost port=xxxxx dbname=regression
+         ->  HashAggregate  (cost=0.02..0.04 rows=2 width=16)
+               Hash Key: NULL::integer
+               Hash Key: NULL::integer
+               ->  Result  (cost=0.00..0.01 rows=1 width=8)
+                     One-Time Filter: (false AND false)
+(10 rows)
+
+-- Cleanup
+\c - - - :master_port
+DROP TABLE test, ref, local;
+-- Remove the coordinator again
+SELECT 1 FROM master_remove_node('localhost', :master_port);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+
+-- Remove the secondary coordinator again
+SELECT 1 FROM master_remove_node('localhost', :follower_master_port);
+ ?column?
+---------------------------------------------------------------------
+        1
+(1 row)
+

src/test/regress/multi_follower_schedule

@@ -1,4 +1,5 @@
 test: multi_follower_sanity_check
+test: follower_single_node
 test: multi_follower_select_statements
 test: multi_follower_dml
 test: multi_follower_configure_followers

src/test/regress/sql/follower_single_node.sql

@@ -0,0 +1,93 @@
+\c - - - :master_port
+SET citus.shard_count TO 4;
+SET citus.shard_replication_factor TO 1;
+SET citus.next_shard_id TO 93630500;
+
+SELECT 1 FROM master_add_node('localhost', :master_port, groupid => 0);
+SELECT 1 FROM master_set_node_property('localhost', :master_port, 'shouldhaveshards', true);
+
+CREATE TABLE test(x int, y int);
+SELECT create_distributed_table('test','x');
+CREATE TABLE ref(a int, b int);
+SELECT create_reference_table('ref');
+CREATE TABLE local(c int, d int);
+
+INSERT INTO test VALUES (1, 2), (3, 4), (5, 6), (2, 7), (4, 5);
+INSERT INTO ref VALUES (1, 2), (5, 6), (7, 8);
+INSERT INTO local VALUES (1, 2), (3, 4), (7, 8);
+
+-- connect to the follower and check that a simple select query works, the follower
+-- is still in the default cluster and will send queries to the primary nodes
+\c - - - :follower_master_port
+SELECT * FROM test WHERE x = 1;
+SELECT count(*) FROM test;
+SELECT * FROM test ORDER BY x;
+
+SELECT count(*) FROM ref;
+SELECT * FROM ref ORDER BY a;
+SELECT * FROM test, ref WHERE x = a ORDER BY x;
+
+SELECT count(*) FROM local;
+SELECT * FROM local ORDER BY c;
+SELECT * FROM ref, local WHERE a = c ORDER BY a;
+
+-- Check repartion joins are support
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+SET citus.enable_repartition_joins TO ON;
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+RESET citus.enable_repartition_joins;
+
+-- Confirm that dummy placements work
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+-- Confirm that they work with round-robin task assignment policy
+SET citus.task_assignment_policy TO 'round-robin';
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+
+-- now, connect to the follower but tell it to use secondary nodes. There are no
+-- secondary nodes so this should fail.
+
+-- (this is :follower_master_port but substitution doesn't work here)
+\c "port=9070 dbname=regression options='-c\ citus.use_secondary_nodes=always'"
+
+SELECT * FROM test WHERE x = 1;
+
+-- add the the follower as secondary nodes and try again, the SELECT statement
+-- should work this time
+\c - - - :master_port
+
+SELECT 1 FROM master_add_node('localhost', :follower_master_port, groupid => 0, noderole => 'secondary');
+SELECT 1 FROM master_set_node_property('localhost', :master_port, 'shouldhaveshards', true);
+
+\c "port=9070 dbname=regression options='-c\ citus.use_secondary_nodes=always'"
+
+SELECT * FROM test WHERE x = 1;
+SELECT count(*) FROM test;
+SELECT * FROM test ORDER BY x;
+
+SELECT count(*) FROM ref;
+SELECT * FROM ref ORDER BY a;
+SELECT * FROM test, ref WHERE x = a ORDER BY x;
+
+SELECT count(*) FROM local;
+SELECT * FROM local ORDER BY c;
+SELECT * FROM ref, local WHERE a = c ORDER BY a;
+
+-- Check repartion joins are support
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+SET citus.enable_repartition_joins TO ON;
+SELECT * FROM test t1, test t2 WHERE t1.x = t2.y ORDER BY t1.x;
+RESET citus.enable_repartition_joins;
+
+-- Confirm that dummy placements work
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+-- Confirm that they work with round-robin task assignment policy
+SET citus.task_assignment_policy TO 'round-robin';
+EXPLAIN SELECT sum(x) FROM test WHERE false GROUP BY GROUPING SETS (x,y);
+
+-- Cleanup
+\c - - - :master_port
+DROP TABLE test, ref, local;
+-- Remove the coordinator again
+SELECT 1 FROM master_remove_node('localhost', :master_port);
+-- Remove the secondary coordinator again
+SELECT 1 FROM master_remove_node('localhost', :follower_master_port);