citus/src/test/regress/expected/remove_coordinator.out

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-- removing coordinator from pg_dist_node should update pg_dist_colocation
SELECT master_remove_node('localhost', :master_port);
master_remove_node
---------------------------------------------------------------------
(1 row)
-- to silence -potentially flaky- "could not establish connection after" warnings in below test
SET client_min_messages TO ERROR;
-- to fail fast when the hostname is not resolvable, as it will be the case below
SET citus.node_connection_timeout to '1s';
BEGIN;
SET application_name TO 'new_app_name';
-- that should fail because of bad hostname & port
SELECT citus_add_node('200.200.200.200', 1, 200);
ERROR: connection to the remote node postgres@200.200.200.200:1 failed
-- Since above command failed, now Postgres will need to revert the
-- application_name change made in this transaction and this will
-- happen within abort-transaction callback, so we won't be in a
-- transaction block while Postgres does that.
--
-- And when the application_name changes, Citus tries to re-assign
-- the global pid but it does so only for Citus internal backends,
-- and doing so for Citus internal backends doesn't require being
-- in a transaction block and is safe.
--
-- However, for the client external backends (like us here), Citus
-- doesn't re-assign the global pid because it's not needed and it's
-- not safe to do so outside of a transaction block. This is because,
-- it would require performing a catalog access to retrive the local
-- node id when the cached local node is invalidated like what just
-- happened here because of the failed citus_add_node() call made
-- above.
--
-- So by failing here (rather than crashing), we ensure this behavior.
ROLLBACK;
RESET client_min_messages;
RESET citus.node_connection_timeout;
-- restore coordinator for the rest of the tests
SELECT citus_set_coordinator_host('localhost', :master_port);
citus_set_coordinator_host
---------------------------------------------------------------------
(1 row)