mirror of
https://github.com/timescale/timescaledb.git
synced 2025-06-02 19:26:43 +08:00
b2a15b8b81
Previously, accounting for BGWs assigned to DB schedulers was incorrect, because NULL scheduler handlers were translating to BGW_STOPPED. This caused the accounter to decrement BGW_counter despite the counter never being incremented. We fix this by imposing the invariant that entries for schedulers should be not be created in the hash table until they have grabbed a slot via the bgw_counter. Also did some cleanup with respect to the message-handling functions. In particular, message_restart_action is now a true-restart rather than a force-restart.
357 lines
11 KiB
Plaintext
357 lines
11 KiB
Plaintext
\c single_2 :ROLE_SUPERUSER
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\ir include/bgw_launcher_utils.sql
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/*
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* Note on testing: need a couple wrappers that pg_sleep in a loop to wait for changes
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* to appear in pg_stat_activity.
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* Further Note: PG 9.6 changed what appeared in pg_stat_activity, so the launcher doesn't actually show up.
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* we can still test its interactions with its children, but can't test some of the things specific to the launcher.
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* So we've added some bits about the version number as needed.
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*/
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CREATE VIEW worker_counts as SELECT count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Launcher') as launcher,
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count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Scheduler' AND datname = 'single') as single_scheduler,
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count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Scheduler' AND datname = 'single_2') as single_2_scheduler,
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count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Scheduler' AND datname = 'template1') as template1_scheduler
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FROM pg_stat_activity;
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CREATE FUNCTION wait_worker_counts(launcher_ct INTEGER, scheduler1_ct INTEGER, scheduler2_ct INTEGER, template1_ct INTEGER) RETURNS BOOLEAN LANGUAGE PLPGSQL AS
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$BODY$
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DECLARE
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r INTEGER;
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BEGIN
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FOR i in 1..10
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LOOP
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SELECT COUNT(*) from worker_counts where (launcher = launcher_ct OR current_setting('server_version_num')::int < 100000)
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AND single_scheduler = scheduler1_ct AND single_2_scheduler = scheduler2_ct and template1_scheduler = template1_ct into r;
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if(r < 1) THEN
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PERFORM pg_sleep(0.1);
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PERFORM pg_stat_clear_snapshot();
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ELSE
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--We have the correct counts!
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RETURN TRUE;
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END IF;
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END LOOP;
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RETURN FALSE;
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END
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$BODY$;
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/*
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* When we've connected to single_2, we should be able to see the cluster launcher
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* and the scheduler for single in pg_stat_activity
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* but single_2 shouldn't have a scheduler because ext not created yet
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*/
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SELECT wait_worker_counts(1,1,0,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/*Now create the extension in single_2*/
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SET client_min_messages = ERROR;
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CREATE EXTENSION timescaledb CASCADE;
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RESET client_min_messages;
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SELECT wait_worker_counts(1,1,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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DROP DATABASE single;
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/* Now the db_scheduler for single should have disappeared*/
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SELECT wait_worker_counts(1,0,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/*Now let's restart the scheduler and make sure our backend_start changed */
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SELECT backend_start as orig_backend_start
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2' \gset
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/* We'll do this in a txn so that we can see that the worker locks on our txn before continuing*/
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BEGIN;
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SELECT _timescaledb_internal.restart_background_workers();
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restart_background_workers
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----------------------------
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t
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(1 row)
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SELECT wait_worker_counts(1,0,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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SELECT (backend_start > :'orig_backend_start'::timestamptz) backend_start_changed,
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(wait_event = 'virtualxid') wait_event_changed
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2';
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backend_start_changed | wait_event_changed
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-----------------------+--------------------
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t | t
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(1 row)
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COMMIT;
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SELECT wait_worker_counts(1,0,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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SELECT (wait_event IS DISTINCT FROM 'virtualxid') wait_event_changed
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2';
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wait_event_changed
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--------------------
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t
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(1 row)
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/*Test stop*/
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SELECT _timescaledb_internal.stop_background_workers();
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stop_background_workers
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-------------------------
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t
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(1 row)
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SELECT wait_worker_counts(1,0,0,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/*Make sure it doesn't break if we stop twice in a row*/
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SELECT _timescaledb_internal.stop_background_workers();
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stop_background_workers
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-------------------------
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t
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(1 row)
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SELECT wait_worker_counts(1,0,0,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/*test start*/
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SELECT _timescaledb_internal.start_background_workers();
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start_background_workers
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--------------------------
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t
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(1 row)
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SELECT wait_worker_counts(1,0,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/*make sure start is idempotent*/
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SELECT backend_start as orig_backend_start
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2' \gset
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/* Since we're doing idempotency tests, we're also going to exercise our queue and start 20 times*/
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SELECT _timescaledb_internal.start_background_workers() as start_background_workers, * FROM generate_series(1,20);
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start_background_workers | generate_series
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--------------------------+-----------------
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t | 1
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t | 2
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t | 3
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t | 4
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t | 5
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t | 6
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t | 7
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t | 8
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t | 9
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t | 10
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t | 11
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t | 12
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t | 13
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t | 14
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t | 15
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t | 16
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t | 17
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t | 18
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t | 19
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t | 20
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(20 rows)
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/*Here we're waiting to see if something shows up in pg_stat_activity,
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* so we have to condition our loop in the opposite way. We'll only wait
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* half a second in total as well so that tests don't take too long. */
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CREATE FUNCTION wait_equals(TIMESTAMPTZ) RETURNS BOOLEAN LANGUAGE PLPGSQL AS
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$BODY$
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DECLARE
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r BOOLEAN;
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BEGIN
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FOR i in 1..5
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LOOP
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SELECT (backend_start = $1::timestamptz) backend_start_unchanged
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2' into r;
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if(r) THEN
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PERFORM pg_sleep(0.1);
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PERFORM pg_stat_clear_snapshot();
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ELSE
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RETURN FALSE;
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END IF;
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END LOOP;
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RETURN TRUE;
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END
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$BODY$;
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select wait_equals(:'orig_backend_start');
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wait_equals
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-------------
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t
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(1 row)
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SELECT _timescaledb_internal.restart_background_workers();
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restart_background_workers
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----------------------------
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t
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(1 row)
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SELECT wait_worker_counts(1,0,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/*Make sure drop extension statement restarts the worker and on rollback it keeps running*/
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/*Now let's restart the scheduler and make sure our backend_start changed */
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SELECT backend_start as orig_backend_start
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2' \gset
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BEGIN;
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DROP EXTENSION timescaledb;
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SELECT wait_worker_counts(1,0,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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ROLLBACK;
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CREATE FUNCTION wait_greater(TIMESTAMPTZ) RETURNS BOOLEAN LANGUAGE PLPGSQL AS
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$BODY$
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DECLARE
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r BOOLEAN;
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BEGIN
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FOR i in 1..10
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LOOP
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SELECT (backend_start > $1::timestamptz) backend_start_changed
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2' into r;
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if(NOT r) THEN
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PERFORM pg_sleep(0.1);
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PERFORM pg_stat_clear_snapshot();
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ELSE
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RETURN TRUE;
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END IF;
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END LOOP;
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RETURN FALSE;
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END
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$BODY$;
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SELECT wait_greater(:'orig_backend_start');
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wait_greater
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--------------
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t
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(1 row)
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/* Make sure canceling the launcher backend causes a restart of schedulers */
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SELECT backend_start as orig_backend_start
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FROM pg_stat_activity
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WHERE application_name = 'TimescaleDB Background Worker Scheduler'
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AND datname = 'single_2' \gset
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SELECT coalesce(
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(SELECT pg_cancel_backend(pid) FROM pg_stat_activity WHERE application_name = 'TimescaleDB Background Worker Launcher'),
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(SELECT current_setting('server_version_num')::int < 100000));
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coalesce
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----------
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t
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(1 row)
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SELECT wait_worker_counts(1,0,1,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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SELECT ((current_setting('server_version_num')::int < 100000) OR wait_greater(:'orig_backend_start')) as wait_greater;
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wait_greater
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--------------
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t
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(1 row)
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/* Make sure dropping the extension means that the scheduler is stopped*/
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BEGIN;
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DROP EXTENSION timescaledb;
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COMMIT;
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SELECT wait_worker_counts(1,0,0,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/* Connect to the template1 database */
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\c template1
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\ir include/bgw_launcher_utils.sql
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/*
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* Note on testing: need a couple wrappers that pg_sleep in a loop to wait for changes
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* to appear in pg_stat_activity.
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* Further Note: PG 9.6 changed what appeared in pg_stat_activity, so the launcher doesn't actually show up.
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* we can still test its interactions with its children, but can't test some of the things specific to the launcher.
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* So we've added some bits about the version number as needed.
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*/
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CREATE VIEW worker_counts as SELECT count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Launcher') as launcher,
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count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Scheduler' AND datname = 'single') as single_scheduler,
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count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Scheduler' AND datname = 'single_2') as single_2_scheduler,
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count(*) filter (WHERE application_name = 'TimescaleDB Background Worker Scheduler' AND datname = 'template1') as template1_scheduler
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FROM pg_stat_activity;
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CREATE FUNCTION wait_worker_counts(launcher_ct INTEGER, scheduler1_ct INTEGER, scheduler2_ct INTEGER, template1_ct INTEGER) RETURNS BOOLEAN LANGUAGE PLPGSQL AS
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$BODY$
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DECLARE
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r INTEGER;
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BEGIN
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FOR i in 1..10
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LOOP
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SELECT COUNT(*) from worker_counts where (launcher = launcher_ct OR current_setting('server_version_num')::int < 100000)
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AND single_scheduler = scheduler1_ct AND single_2_scheduler = scheduler2_ct and template1_scheduler = template1_ct into r;
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if(r < 1) THEN
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PERFORM pg_sleep(0.1);
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PERFORM pg_stat_clear_snapshot();
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ELSE
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--We have the correct counts!
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RETURN TRUE;
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END IF;
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END LOOP;
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RETURN FALSE;
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END
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$BODY$;
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BEGIN;
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/* Then create extension there in a txn and make sure we see a scheduler start */
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SET client_min_messages = ERROR;
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CREATE EXTENSION timescaledb CASCADE;
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RESET client_min_messages;
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SELECT wait_worker_counts(1,0,0,1);
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wait_worker_counts
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--------------------
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t
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(1 row)
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COMMIT;
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/* End our transaction and it should immediately exit because it's a template database.*/
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SELECT wait_worker_counts(1,0,0,0);
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wait_worker_counts
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--------------------
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t
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(1 row)
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/* Clean up after ourselves */
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\ir include/bgw_launcher_utils_cleanup.sql
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DROP FUNCTION wait_worker_counts(integer, integer, integer, integer);
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DROP VIEW worker_counts;
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DROP EXTENSION timescaledb;
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