180 lines
6.3 KiB
PL/PgSQL
180 lines
6.3 KiB
PL/PgSQL
--
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-- Test Statistics Collector
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--
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-- Must be run after tenk2 has been created (by create_table),
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-- populated (by create_misc) and indexed (by create_index).
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--
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-- conditio sine qua non
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SHOW track_counts; -- must be on
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-- ensure that both seqscan and indexscan plans are allowed
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SET enable_seqscan TO on;
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SET enable_indexscan TO on;
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-- for the moment, we don't want index-only scans here
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SET enable_indexonlyscan TO off;
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-- save counters
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CREATE TABLE prevstats AS
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SELECT t.seq_scan, t.seq_tup_read, t.idx_scan, t.idx_tup_fetch,
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(b.heap_blks_read + b.heap_blks_hit) AS heap_blks,
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(b.idx_blks_read + b.idx_blks_hit) AS idx_blks,
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pg_stat_get_snapshot_timestamp() as snap_ts
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FROM pg_catalog.pg_stat_user_tables AS t,
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pg_catalog.pg_statio_user_tables AS b
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WHERE t.relname='tenk2' AND b.relname='tenk2';
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-- function to wait for counters to advance
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create function wait_for_stats() returns void as $$
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declare
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start_time timestamptz := clock_timestamp();
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updated1 bool;
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updated2 bool;
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updated3 bool;
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updated4 bool;
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begin
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-- we don't want to wait forever; loop will exit after 30 seconds
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for i in 1 .. 300 loop
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-- With parallel query, the seqscan and indexscan on tenk2 might be done
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-- in parallel worker processes, which will send their stats counters
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-- asynchronously to what our own session does. So we must check for
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-- those counts to be registered separately from the update counts.
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-- check to see if seqscan has been sensed
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SELECT (st.seq_scan >= pr.seq_scan + 1) INTO updated1
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FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
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WHERE st.relname='tenk2' AND cl.relname='tenk2';
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-- check to see if indexscan has been sensed
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SELECT (st.idx_scan >= pr.idx_scan + 1) INTO updated2
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FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
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WHERE st.relname='tenk2' AND cl.relname='tenk2';
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-- check to see if all updates have been sensed
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SELECT (n_tup_ins > 0) INTO updated3
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FROM pg_stat_user_tables WHERE relname='trunc_stats_test4';
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-- We must also check explicitly that pg_stat_get_snapshot_timestamp has
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-- advanced, because that comes from the global stats file which might
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-- be older than the per-DB stats file we got the other values from.
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SELECT (pr.snap_ts < pg_stat_get_snapshot_timestamp()) INTO updated4
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FROM prevstats AS pr;
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exit when updated1 and updated2 and updated3 and updated4;
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-- wait a little
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perform pg_sleep_for('100 milliseconds');
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-- reset stats snapshot so we can test again
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perform pg_stat_clear_snapshot();
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end loop;
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-- report time waited in postmaster log (where it won't change test output)
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raise log 'wait_for_stats delayed % seconds',
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extract(epoch from clock_timestamp() - start_time);
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end
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$$ language plpgsql;
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-- test effects of TRUNCATE on n_live_tup/n_dead_tup counters
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CREATE TABLE trunc_stats_test(id serial);
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CREATE TABLE trunc_stats_test1(id serial, stuff text);
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CREATE TABLE trunc_stats_test2(id serial);
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CREATE TABLE trunc_stats_test3(id serial, stuff text);
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CREATE TABLE trunc_stats_test4(id serial);
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-- check that n_live_tup is reset to 0 after truncate
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INSERT INTO trunc_stats_test DEFAULT VALUES;
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INSERT INTO trunc_stats_test DEFAULT VALUES;
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INSERT INTO trunc_stats_test DEFAULT VALUES;
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TRUNCATE trunc_stats_test;
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-- test involving a truncate in a transaction; 4 ins but only 1 live
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INSERT INTO trunc_stats_test1 DEFAULT VALUES;
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INSERT INTO trunc_stats_test1 DEFAULT VALUES;
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INSERT INTO trunc_stats_test1 DEFAULT VALUES;
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UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
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DELETE FROM trunc_stats_test1 WHERE id = 3;
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BEGIN;
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UPDATE trunc_stats_test1 SET id = id + 100;
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TRUNCATE trunc_stats_test1;
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INSERT INTO trunc_stats_test1 DEFAULT VALUES;
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COMMIT;
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-- use a savepoint: 1 insert, 1 live
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BEGIN;
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INSERT INTO trunc_stats_test2 DEFAULT VALUES;
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INSERT INTO trunc_stats_test2 DEFAULT VALUES;
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SAVEPOINT p1;
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INSERT INTO trunc_stats_test2 DEFAULT VALUES;
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TRUNCATE trunc_stats_test2;
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INSERT INTO trunc_stats_test2 DEFAULT VALUES;
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RELEASE SAVEPOINT p1;
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COMMIT;
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-- rollback a savepoint: this should count 4 inserts and have 2
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-- live tuples after commit (and 2 dead ones due to aborted subxact)
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BEGIN;
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INSERT INTO trunc_stats_test3 DEFAULT VALUES;
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INSERT INTO trunc_stats_test3 DEFAULT VALUES;
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SAVEPOINT p1;
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INSERT INTO trunc_stats_test3 DEFAULT VALUES;
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INSERT INTO trunc_stats_test3 DEFAULT VALUES;
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TRUNCATE trunc_stats_test3;
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INSERT INTO trunc_stats_test3 DEFAULT VALUES;
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ROLLBACK TO SAVEPOINT p1;
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COMMIT;
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-- rollback a truncate: this should count 2 inserts and produce 2 dead tuples
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BEGIN;
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INSERT INTO trunc_stats_test4 DEFAULT VALUES;
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INSERT INTO trunc_stats_test4 DEFAULT VALUES;
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TRUNCATE trunc_stats_test4;
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INSERT INTO trunc_stats_test4 DEFAULT VALUES;
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ROLLBACK;
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-- do a seqscan
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SELECT count(*) FROM tenk2;
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-- do an indexscan
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-- make sure it is not a bitmap scan, which might skip fetching heap tuples
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SET enable_bitmapscan TO off;
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SELECT count(*) FROM tenk2 WHERE unique1 = 1;
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RESET enable_bitmapscan;
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-- We can't just call wait_for_stats() at this point, because we only
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-- transmit stats when the session goes idle, and we probably didn't
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-- transmit the last couple of counts yet thanks to the rate-limiting logic
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-- in pgstat_report_stat(). But instead of waiting for the rate limiter's
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-- timeout to elapse, let's just start a new session. The old one will
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-- then send its stats before dying.
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\c -
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-- wait for stats collector to update
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SELECT wait_for_stats();
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-- check effects
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SELECT relname, n_tup_ins, n_tup_upd, n_tup_del, n_live_tup, n_dead_tup
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FROM pg_stat_user_tables
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WHERE relname like 'trunc_stats_test%' order by relname;
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SELECT st.seq_scan >= pr.seq_scan + 1,
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st.seq_tup_read >= pr.seq_tup_read + cl.reltuples,
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st.idx_scan >= pr.idx_scan + 1,
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st.idx_tup_fetch >= pr.idx_tup_fetch + 1
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FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
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WHERE st.relname='tenk2' AND cl.relname='tenk2';
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SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages,
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st.idx_blks_read + st.idx_blks_hit >= pr.idx_blks + 1
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FROM pg_statio_user_tables AS st, pg_class AS cl, prevstats AS pr
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WHERE st.relname='tenk2' AND cl.relname='tenk2';
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SELECT pr.snap_ts < pg_stat_get_snapshot_timestamp() as snapshot_newer
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FROM prevstats AS pr;
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DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
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DROP TABLE prevstats;
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-- End of Stats Test
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