-- -- failure_connection_establishment.sql tests some behaviour of connection management when -- it fails to connect. -- -- Failure cases covered: -- - timeout -- SELECT citus.mitmproxy('conn.allow()'); CREATE SCHEMA fail_connect; SET search_path TO 'fail_connect'; SET citus.shard_count TO 4; SET citus.max_cached_conns_per_worker TO 0; ALTER SEQUENCE pg_catalog.pg_dist_shardid_seq RESTART 1450000; ALTER SEQUENCE pg_catalog.pg_dist_placement_placementid_seq RESTART 1450000; CREATE TABLE products ( product_no integer, name text, price numeric ); SELECT create_distributed_table('products', 'product_no'); -- Can only add primary key constraint on distribution column (or group of columns -- including distribution column) -- Command below should error out since 'name' is not a distribution column ALTER TABLE products ADD CONSTRAINT p_key PRIMARY KEY(name); -- we will insert a connection delay here as this query was the cause for an investigation -- into connection establishment problems SET citus.node_connection_timeout TO 400; SELECT citus.mitmproxy('conn.delay(500)'); ALTER TABLE products ADD CONSTRAINT p_key PRIMARY KEY(product_no); SELECT citus.mitmproxy('conn.allow()'); CREATE TABLE r1 ( id int PRIMARY KEY, name text ); INSERT INTO r1 (id, name) VALUES (1,'foo'), (2,'bar'), (3,'baz'); SELECT create_reference_table('r1'); SELECT citus.clear_network_traffic(); SELECT citus.mitmproxy('conn.delay(500)'); -- we cannot control which replica of the reference table will be queried and there is -- only one specific client we can control the connection for. -- by using round-robin task_assignment_policy we can force to hit both machines. We will -- use two output files to match both orders to verify there is 1 that times out and falls -- through to read from the other machine SET citus.task_assignment_policy TO 'round-robin'; -- suppress the warning since we can't control which shard is chose first. Failure of this -- test would be if one of the queries does not return the result but an error. SET client_min_messages TO ERROR; SELECT name FROM r1 WHERE id = 2; SELECT name FROM r1 WHERE id = 2; -- verify a connection attempt was made to the intercepted node, this would have cause the -- connection to have been delayed and thus caused a timeout SELECT citus.dump_network_traffic(); RESET client_min_messages; -- verify get_global_active_transactions works when a timeout happens on a connection SELECT get_global_active_transactions(); SELECT citus.mitmproxy('conn.allow()'); DROP SCHEMA fail_connect CASCADE; SET search_path TO default;