@ -28,63 +28,6 @@ SELECT t.seq_scan, t.seq_tup_read, t.idx_scan, t.idx_tup_fetch,
pg_catalog.pg_statio_user_tables AS b
WHERE t.relname='tenk2' AND b.relname='tenk2';
COMMIT;
-- function to wait for counters to advance
create function wait_for_stats() returns void as $$
declare
start_time timestamptz := clock_timestamp();
updated1 bool;
updated2 bool;
updated3 bool;
updated4 bool;
begin
SET LOCAL stats_fetch_consistency = snapshot;
-- We don't want to wait forever. No timeout suffices if the OS drops our
-- stats traffic because an earlier test file left a full UDP buffer.
-- Hence, don't use PG_TEST_TIMEOUT_DEFAULT, which may be large for
-- can't-happen timeouts. Exit after 30 seconds.
for i in 1 .. 300 loop
-- With parallel query, the seqscan and indexscan on tenk2 might be done
-- in parallel worker processes, which will send their stats counters
-- asynchronously to what our own session does. So we must check for
-- those counts to be registered separately from the update counts.
-- check to see if seqscan has been sensed
SELECT (st.seq_scan >= pr.seq_scan + 1) INTO updated1
FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
WHERE st.relname='tenk2' AND cl.relname='tenk2';
-- check to see if indexscan has been sensed
SELECT (st.idx_scan >= pr.idx_scan + 1) INTO updated2
FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
WHERE st.relname='tenk2' AND cl.relname='tenk2';
-- check to see if all updates have been sensed
SELECT (n_tup_ins > 0) INTO updated3
FROM pg_stat_user_tables WHERE relname='trunc_stats_test4';
-- We must also check explicitly that pg_stat_get_snapshot_timestamp has
-- advanced, because that comes from the global stats file which might
-- be older than the per-DB stats file we got the other values from.
SELECT (pr.snap_ts < pg_stat_get_snapshot_timestamp()) INTO updated4
FROM prevstats AS pr;
exit when updated1 and updated2 and updated3 and updated4;
-- wait a little
perform pg_sleep_for('100 milliseconds');
-- reset stats snapshot so we can test again
perform pg_stat_clear_snapshot();
end loop;
-- report time waited in postmaster log (where it won't change test output)
raise log 'wait_for_stats delayed % seconds',
extract(epoch from clock_timestamp() - start_time);
end
$$ language plpgsql;
-- test effects of TRUNCATE on n_live_tup/n_dead_tup counters
CREATE TABLE trunc_stats_test(id serial);
CREATE TABLE trunc_stats_test1(id serial, stuff text);
@ -153,17 +96,10 @@ SELECT count(*) FROM tenk2 WHERE unique1 = 1;
(1 row)
RESET enable_bitmapscan;
-- We can't just call wait_for_stats() at this point, because we only
-- transmit stats when the session goes idle, and we probably didn't
-- transmit the last couple of counts yet thanks to the rate-limiting logic
-- in pgstat_report_stat(). But instead of waiting for the rate limiter's
-- timeout to elapse, let's just start a new session. The old one will
-- then send its stats before dying.
\c -
-- wait for stats collector to update
SELECT wait_for_stats();
wait_for_stats
----------------
-- ensure pending stats are flushed
SELECT pg_stat_force_next_flush();
pg_stat_force_next_flush
--------------------------
(1 row)
@ -212,57 +148,6 @@ FROM prevstats AS pr;
COMMIT;
DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
DROP TABLE prevstats;
-- test BRIN index doesn't block HOT update - we include this test here, as it
-- relies on statistics collector and so it may occasionally fail, especially
-- on slower systems
CREATE TABLE brin_hot (
id integer PRIMARY KEY,
val integer NOT NULL
) WITH (autovacuum_enabled = off, fillfactor = 70);
INSERT INTO brin_hot SELECT *, 0 FROM generate_series(1, 235);
CREATE INDEX val_brin ON brin_hot using brin(val);
CREATE FUNCTION wait_for_hot_stats() RETURNS void AS $$
DECLARE
start_time timestamptz := clock_timestamp();
updated bool;
BEGIN
-- we don't want to wait forever; loop will exit after 30 seconds
FOR i IN 1 .. 300 LOOP
SELECT (pg_stat_get_tuples_hot_updated('brin_hot'::regclass::oid) > 0) INTO updated;
EXIT WHEN updated;
-- wait a little
PERFORM pg_sleep_for('100 milliseconds');
-- reset stats snapshot so we can test again
PERFORM pg_stat_clear_snapshot();
END LOOP;
-- report time waited in postmaster log (where it won't change test output)
RAISE log 'wait_for_hot_stats delayed % seconds',
EXTRACT(epoch FROM clock_timestamp() - start_time);
END
$$ LANGUAGE plpgsql;
UPDATE brin_hot SET val = -3 WHERE id = 42;
-- We can't just call wait_for_hot_stats() at this point, because we only
-- transmit stats when the session goes idle, and we probably didn't
-- transmit the last couple of counts yet thanks to the rate-limiting logic
-- in pgstat_report_stat(). But instead of waiting for the rate limiter's
-- timeout to elapse, let's just start a new session. The old one will
-- then send its stats before dying.
\c -
SELECT wait_for_hot_stats();
wait_for_hot_stats
--------------------
(1 row)
SELECT pg_stat_get_tuples_hot_updated('brin_hot'::regclass::oid);
pg_stat_get_tuples_hot_updated
--------------------------------
1
(1 row)
DROP TABLE brin_hot;
DROP FUNCTION wait_for_hot_stats();
-- ensure that stats accessors handle NULL input correctly
SELECT pg_stat_get_replication_slot(NULL);
pg_stat_get_replication_slot
Andres Freund
3 years ago