@ -556,6 +556,208 @@ SELECT pg_stat_get_live_tuples(:drop_stats_test_subxact_oid);
DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
DROP TABLE prevstats;
-----
-- Test that last_seq_scan, last_idx_scan are correctly maintained
--
-- Perform test using a temporary table. That way autovacuum etc won't
-- interfere. To be able to check that timestamps increase, we sleep for 100ms
-- between tests, assuming that there aren't systems with a coarser timestamp
-- granularity.
-----
BEGIN;
CREATE TEMPORARY TABLE test_last_scan(idx_col int primary key, noidx_col int);
INSERT INTO test_last_scan(idx_col, noidx_col) VALUES(1, 1);
SELECT pg_stat_force_next_flush();
pg_stat_force_next_flush
--------------------------
(1 row)
COMMIT;
SELECT pg_stat_reset_single_table_counters('test_last_scan'::regclass);
pg_stat_reset_single_table_counters
-------------------------------------
(1 row)
SELECT seq_scan, idx_scan FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass;
seq_scan | idx_scan
----------+----------
0 | 0
(1 row)
-- ensure we start out with exactly one index and sequential scan
BEGIN;
SET LOCAL enable_seqscan TO on;
SET LOCAL enable_indexscan TO on;
SET LOCAL enable_bitmapscan TO off;
EXPLAIN (COSTS off) SELECT count(*) FROM test_last_scan WHERE noidx_col = 1;
QUERY PLAN
----------------------------------
Aggregate
-> Seq Scan on test_last_scan
Filter: (noidx_col = 1)
(3 rows)
SELECT count(*) FROM test_last_scan WHERE noidx_col = 1;
count
-------
1
(1 row)
SET LOCAL enable_seqscan TO off;
EXPLAIN (COSTS off) SELECT count(*) FROM test_last_scan WHERE idx_col = 1;
QUERY PLAN
--------------------------------------------------------------
Aggregate
-> Index Scan using test_last_scan_pkey on test_last_scan
Index Cond: (idx_col = 1)
(3 rows)
SELECT count(*) FROM test_last_scan WHERE idx_col = 1;
count
-------
1
(1 row)
SELECT pg_stat_force_next_flush();
pg_stat_force_next_flush
--------------------------
(1 row)
COMMIT;
-- fetch timestamps from before the next test
SELECT last_seq_scan AS test_last_seq, last_idx_scan AS test_last_idx
FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass \gset
SELECT pg_sleep(0.1); -- assume a minimum timestamp granularity of 100ms
pg_sleep
----------
(1 row)
-- cause one sequential scan
BEGIN;
SET LOCAL enable_seqscan TO on;
SET LOCAL enable_indexscan TO off;
SET LOCAL enable_bitmapscan TO off;
EXPLAIN (COSTS off) SELECT count(*) FROM test_last_scan WHERE noidx_col = 1;
QUERY PLAN
----------------------------------
Aggregate
-> Seq Scan on test_last_scan
Filter: (noidx_col = 1)
(3 rows)
SELECT count(*) FROM test_last_scan WHERE noidx_col = 1;
count
-------
1
(1 row)
SELECT pg_stat_force_next_flush();
pg_stat_force_next_flush
--------------------------
(1 row)
COMMIT;
-- check that just sequential scan stats were incremented
SELECT seq_scan, :'test_last_seq' < last_seq_scan AS seq_ok, idx_scan, :'test_last_idx' = last_idx_scan AS idx_ok
FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass;
seq_scan | seq_ok | idx_scan | idx_ok
----------+--------+----------+--------
2 | t | 1 | t
(1 row)
-- fetch timestamps from before the next test
SELECT last_seq_scan AS test_last_seq, last_idx_scan AS test_last_idx
FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass \gset
SELECT pg_sleep(0.1);
pg_sleep
----------
(1 row)
-- cause one index scan
BEGIN;
SET LOCAL enable_seqscan TO off;
SET LOCAL enable_indexscan TO on;
SET LOCAL enable_bitmapscan TO off;
EXPLAIN (COSTS off) SELECT count(*) FROM test_last_scan WHERE idx_col = 1;
QUERY PLAN
--------------------------------------------------------------
Aggregate
-> Index Scan using test_last_scan_pkey on test_last_scan
Index Cond: (idx_col = 1)
(3 rows)
SELECT count(*) FROM test_last_scan WHERE idx_col = 1;
count
-------
1
(1 row)
SELECT pg_stat_force_next_flush();
pg_stat_force_next_flush
--------------------------
(1 row)
COMMIT;
-- check that just index scan stats were incremented
SELECT seq_scan, :'test_last_seq' = last_seq_scan AS seq_ok, idx_scan, :'test_last_idx' < last_idx_scan AS idx_ok
FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass;
seq_scan | seq_ok | idx_scan | idx_ok
----------+--------+----------+--------
2 | t | 2 | t
(1 row)
-- fetch timestamps from before the next test
SELECT last_seq_scan AS test_last_seq, last_idx_scan AS test_last_idx
FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass \gset
SELECT pg_sleep(0.1);
pg_sleep
----------
(1 row)
-- cause one bitmap index scan
BEGIN;
SET LOCAL enable_seqscan TO off;
SET LOCAL enable_indexscan TO off;
SET LOCAL enable_bitmapscan TO on;
EXPLAIN (COSTS off) SELECT count(*) FROM test_last_scan WHERE idx_col = 1;
QUERY PLAN
------------------------------------------------------
Aggregate
-> Bitmap Heap Scan on test_last_scan
Recheck Cond: (idx_col = 1)
-> Bitmap Index Scan on test_last_scan_pkey
Index Cond: (idx_col = 1)
(5 rows)
SELECT count(*) FROM test_last_scan WHERE idx_col = 1;
count
-------
1
(1 row)
SELECT pg_stat_force_next_flush();
pg_stat_force_next_flush
--------------------------
(1 row)
COMMIT;
-- check that just index scan stats were incremented
SELECT seq_scan, :'test_last_seq' = last_seq_scan AS seq_ok, idx_scan, :'test_last_idx' < last_idx_scan AS idx_ok
FROM pg_stat_all_tables WHERE relid = 'test_last_scan'::regclass;
seq_scan | seq_ok | idx_scan | idx_ok
----------+--------+----------+--------
2 | t | 3 | t
(1 row)
-----
-- Test that various stats views are being properly populated
-----
Andres Freund
3 years ago