--
-- MULTI_DISTRIBUTED_TRANSACTION_ID
-- 
-- Unit tests for distributed transaction id functionality
--
-- get the current transaction id, which should be uninitialized
-- note that we skip printing the databaseId, which might change
-- per run
-- set timezone to a specific value to prevent
-- different values on different servers
SET TIME ZONE 'PST8PDT';
-- should return uninitialized values if not in a transaction
SELECT initiator_node_identifier, transaction_number, transaction_stamp FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number | transaction_stamp 
---------------------------+--------------------+-------------------
                         0 |                  0 | 
(1 row)

BEGIN;
	
	-- we should still see the uninitialized values
	SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number | transaction_stamp | ?column? 
---------------------------+--------------------+-------------------+----------
                         0 |                  0 |                   | t
(1 row)

	-- now assign a value
    SELECT assign_distributed_transaction_id(50, 50, '2016-01-01 00:00:00+0');
 assign_distributed_transaction_id 
-----------------------------------
 
(1 row)

    -- see the assigned value
	SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number |      transaction_stamp       | ?column? 
---------------------------+--------------------+------------------------------+----------
                        50 |                 50 | Thu Dec 31 16:00:00 2015 PST | t
(1 row)

	-- a backend cannot be assigned another tx id if already assigned
    SELECT assign_distributed_transaction_id(51, 51, '2017-01-01 00:00:00+0');
ERROR:  the backend has already been assigned a transaction id
ROLLBACK;
-- since the transaction finished, we should see the uninitialized values
SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number | transaction_stamp | ?column? 
---------------------------+--------------------+-------------------+----------
                         0 |                  0 |                   | t
(1 row)

-- also see that ROLLBACK (i.e., failures in the transaction) clears the shared memory
BEGIN;
	
	-- we should still see the uninitialized values
	SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number | transaction_stamp | ?column? 
---------------------------+--------------------+-------------------+----------
                         0 |                  0 |                   | t
(1 row)

	-- now assign a value
    SELECT assign_distributed_transaction_id(52, 52, '2015-01-01 00:00:00+0');
 assign_distributed_transaction_id 
-----------------------------------
 
(1 row)

    SELECT 5 / 0;
ERROR:  division by zero
COMMIT;
-- since the transaction errored, we should see the uninitialized values again
	SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number | transaction_stamp | ?column? 
---------------------------+--------------------+-------------------+----------
                         0 |                  0 |                   | t
(1 row)

-- we should also see that a new connection means an uninitialized transaction id
BEGIN;
	
	SELECT assign_distributed_transaction_id(52, 52, '2015-01-01 00:00:00+0');
 assign_distributed_transaction_id 
-----------------------------------
 
(1 row)

	SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number |      transaction_stamp       | ?column? 
---------------------------+--------------------+------------------------------+----------
                        52 |                 52 | Wed Dec 31 16:00:00 2014 PST | t
(1 row)

	\c - - - :master_port
	SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number | transaction_stamp | ?column? 
---------------------------+--------------------+-------------------+----------
                         0 |                  0 |                   | t
(1 row)

-- now show that PREPARE resets the distributed transaction id
BEGIN;
	SELECT assign_distributed_transaction_id(120, 120, '2015-01-01 00:00:00+0');
 assign_distributed_transaction_id 
-----------------------------------
 
(1 row)

	SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number |      transaction_stamp       | ?column? 
---------------------------+--------------------+------------------------------+----------
                       120 |                120 | Wed Dec 31 16:00:00 2014 PST | t
(1 row)

	PREPARE TRANSACTION 'dist_xact_id_test';
-- after the prepare we should see that transaction id is cleared
SELECT initiator_node_identifier, transaction_number, transaction_stamp, (process_id = pg_backend_pid()) FROM get_current_transaction_id();
 initiator_node_identifier | transaction_number | transaction_stamp | ?column? 
---------------------------+--------------------+-------------------+----------
                         0 |                  0 |                   | t
(1 row)

-- cleanup the transaction
ROLLBACK PREPARED 'dist_xact_id_test';
-- set back to the original zone
SET TIME ZONE DEFAULT;