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Simplify tests of postgres_fdw terminating connections 

The tests introduced in 32a9c0b for connections broken and
re-established rely on pg_terminate_backend() for their logic.  When
these were introduced, this function simply sent a signal to a backend
without waiting for the operation to complete, and the tests repeatedly
looked at pg_stat_activity to check if the operation was completed or
not.  Since aaf0432, it is possible to define a timeout to make
pg_terminate_backend() wait for a certain duration, so make use of it,
with a timeout reasonably large enough (3min) to give enough room for
the tests to pass even on slow machines.

Some measurements show that the tests of postgres_fdw are much faster
with this change.  For example, on my laptop, they now take 4s instead
of 6s.

Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACXGY_EfGrMTjKjHy2zi-u1u9rdeioU_fro0T6Jo8t56KQ@mail.gmail.com
This commit is contained in:
Michael Paquier 2021-04-14 14:23:53 +09:00
parent cca57c1d9b
commit 93f4146144
2 changed files with 22 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
contrib/postgres_fdw/expected/postgres_fdw.out
View File

@ -9195,19 +9195,6 @@ WARNING: there is no transaction in progress
-- ===================================================================
-- reestablish new connection
-- ===================================================================
-- Terminate the backend having the specified application_name and wait for
-- the termination to complete.
CREATE OR REPLACE PROCEDURE terminate_backend_and_wait(appname text) AS $$
BEGIN
PERFORM pg_terminate_backend(pid) FROM pg_stat_activity
WHERE application_name = appname;
LOOP
PERFORM * FROM pg_stat_activity WHERE application_name = appname;
EXIT WHEN NOT FOUND;
PERFORM pg_sleep(1), pg_stat_clear_snapshot();
END LOOP;
END;
$$ LANGUAGE plpgsql;
-- Change application_name of remote connection to special one
-- so that we can easily terminate the connection later.
ALTER SERVER loopback OPTIONS (application_name 'fdw_retry_check');
@ -9217,8 +9204,14 @@ SELECT 1 FROM ft1 LIMIT 1;
1
(1 row)
-- Terminate the remote connection.
CALL terminate_backend_and_wait('fdw_retry_check');
-- Terminate the remote connection and wait for the termination to complete.
SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
WHERE application_name = 'fdw_retry_check';
pg_terminate_backend
----------------------
t
(1 row)
-- This query should detect the broken connection when starting new remote
-- transaction, reestablish new connection, and then succeed.
BEGIN;
@ -9231,15 +9224,20 @@ SELECT 1 FROM ft1 LIMIT 1;
-- If the query detects the broken connection when starting new remote
-- subtransaction, it doesn't reestablish new connection and should fail.
-- The text of the error might vary across platforms, so don't show it.
CALL terminate_backend_and_wait('fdw_retry_check');
-- Terminate the remote connection and wait for the termination to complete.
SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
WHERE application_name = 'fdw_retry_check';
pg_terminate_backend
----------------------
t
(1 row)
SAVEPOINT s;
\set VERBOSITY sqlstate
SELECT 1 FROM ft1 LIMIT 1; -- should fail
ERROR: 08006
\set VERBOSITY default
COMMIT;
-- Clean up
DROP PROCEDURE terminate_backend_and_wait(text);
-- =============================================================================
-- test connection invalidation cases and postgres_fdw_get_connections function
-- =============================================================================

26
contrib/postgres_fdw/sql/postgres_fdw.sql
View File

@ -2786,27 +2786,14 @@ ROLLBACK;
-- reestablish new connection
-- ===================================================================
-- Terminate the backend having the specified application_name and wait for
-- the termination to complete.
CREATE OR REPLACE PROCEDURE terminate_backend_and_wait(appname text) AS $$
BEGIN
PERFORM pg_terminate_backend(pid) FROM pg_stat_activity
WHERE application_name = appname;
LOOP
PERFORM * FROM pg_stat_activity WHERE application_name = appname;
EXIT WHEN NOT FOUND;
PERFORM pg_sleep(1), pg_stat_clear_snapshot();
END LOOP;
END;
$$ LANGUAGE plpgsql;
-- Change application_name of remote connection to special one
-- so that we can easily terminate the connection later.
ALTER SERVER loopback OPTIONS (application_name 'fdw_retry_check');
SELECT 1 FROM ft1 LIMIT 1;
-- Terminate the remote connection.
CALL terminate_backend_and_wait('fdw_retry_check');
-- Terminate the remote connection and wait for the termination to complete.
SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
WHERE application_name = 'fdw_retry_check';
-- This query should detect the broken connection when starting new remote
-- transaction, reestablish new connection, and then succeed.
@ -2816,16 +2803,15 @@ SELECT 1 FROM ft1 LIMIT 1;
-- If the query detects the broken connection when starting new remote
-- subtransaction, it doesn't reestablish new connection and should fail.
-- The text of the error might vary across platforms, so don't show it.
CALL terminate_backend_and_wait('fdw_retry_check');
-- Terminate the remote connection and wait for the termination to complete.
SELECT pg_terminate_backend(pid, 180000) FROM pg_stat_activity
WHERE application_name = 'fdw_retry_check';
SAVEPOINT s;
\set VERBOSITY sqlstate
SELECT 1 FROM ft1 LIMIT 1; -- should fail
\set VERBOSITY default
COMMIT;
-- Clean up
DROP PROCEDURE terminate_backend_and_wait(text);
-- =============================================================================
-- test connection invalidation cases and postgres_fdw_get_connections function
-- =============================================================================