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diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
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+--
+-- Test Statistics Collector
+--
+-- Must be run after tenk2 has been created (by create_table),
+-- populated (by create_misc) and indexed (by create_index).
+--
+-- conditio sine qua non
+SHOW track_counts;  -- must be on
+ track_counts 
+--------------
+ on
+(1 row)
+
+-- ensure that both seqscan and indexscan plans are allowed
+SET enable_seqscan TO on;
+SET enable_indexscan TO on;
+-- for the moment, we don't want index-only scans here
+SET enable_indexonlyscan TO off;
+-- save counters
+CREATE TABLE prevstats AS
+SELECT t.seq_scan, t.seq_tup_read, t.idx_scan, t.idx_tup_fetch,
+       (b.heap_blks_read + b.heap_blks_hit) AS heap_blks,
+       (b.idx_blks_read + b.idx_blks_hit) AS idx_blks,
+       pg_stat_get_snapshot_timestamp() as snap_ts
+  FROM pg_catalog.pg_stat_user_tables AS t,
+       pg_catalog.pg_statio_user_tables AS b
+ WHERE t.relname='tenk2' AND b.relname='tenk2';
+-- function to wait for counters to advance
+create function wait_for_stats() returns void as $$
+declare
+  start_time timestamptz := clock_timestamp();
+  updated1 bool;
+  updated2 bool;
+  updated3 bool;
+  updated4 bool;
+begin
+  -- we don't want to wait forever; loop will exit after 30 seconds
+  for i in 1 .. 300 loop
+
+    -- With parallel query, the seqscan and indexscan on tenk2 might be done
+    -- in parallel worker processes, which will send their stats counters
+    -- asynchronously to what our own session does.  So we must check for
+    -- those counts to be registered separately from the update counts.
+
+    -- check to see if seqscan has been sensed
+    SELECT (st.seq_scan >= pr.seq_scan + 1) INTO updated1
+      FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
+     WHERE st.relname='tenk2' AND cl.relname='tenk2';
+
+    -- check to see if indexscan has been sensed
+    SELECT (st.idx_scan >= pr.idx_scan + 1) INTO updated2
+      FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
+     WHERE st.relname='tenk2' AND cl.relname='tenk2';
+
+    -- check to see if all updates have been sensed
+    SELECT (n_tup_ins > 0) INTO updated3
+      FROM pg_stat_user_tables WHERE relname='trunc_stats_test4';
+
+    -- We must also check explicitly that pg_stat_get_snapshot_timestamp has
+    -- advanced, because that comes from the global stats file which might
+    -- be older than the per-DB stats file we got the other values from.
+    SELECT (pr.snap_ts < pg_stat_get_snapshot_timestamp()) INTO updated4
+      FROM prevstats AS pr;
+
+    exit when updated1 and updated2 and updated3 and updated4;
+
+    -- wait a little
+    perform pg_sleep_for('100 milliseconds');
+
+    -- reset stats snapshot so we can test again
+    perform pg_stat_clear_snapshot();
+
+  end loop;
+
+  -- report time waited in postmaster log (where it won't change test output)
+  raise log 'wait_for_stats delayed % seconds',
+    extract(epoch from clock_timestamp() - start_time);
+end
+$$ 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);
+CREATE TABLE trunc_stats_test2(id serial);
+CREATE TABLE trunc_stats_test3(id serial, stuff text);
+CREATE TABLE trunc_stats_test4(id serial);
+-- check that n_live_tup is reset to 0 after truncate
+INSERT INTO trunc_stats_test DEFAULT VALUES;
+INSERT INTO trunc_stats_test DEFAULT VALUES;
+INSERT INTO trunc_stats_test DEFAULT VALUES;
+TRUNCATE trunc_stats_test;
+-- test involving a truncate in a transaction; 4 ins but only 1 live
+INSERT INTO trunc_stats_test1 DEFAULT VALUES;
+INSERT INTO trunc_stats_test1 DEFAULT VALUES;
+INSERT INTO trunc_stats_test1 DEFAULT VALUES;
+UPDATE trunc_stats_test1 SET id = id + 10 WHERE id IN (1, 2);
+DELETE FROM trunc_stats_test1 WHERE id = 3;
+BEGIN;
+UPDATE trunc_stats_test1 SET id = id + 100;
+TRUNCATE trunc_stats_test1;
+INSERT INTO trunc_stats_test1 DEFAULT VALUES;
+COMMIT;
+-- use a savepoint: 1 insert, 1 live
+BEGIN;
+INSERT INTO trunc_stats_test2 DEFAULT VALUES;
+INSERT INTO trunc_stats_test2 DEFAULT VALUES;
+SAVEPOINT p1;
+INSERT INTO trunc_stats_test2 DEFAULT VALUES;
+TRUNCATE trunc_stats_test2;
+INSERT INTO trunc_stats_test2 DEFAULT VALUES;
+RELEASE SAVEPOINT p1;
+COMMIT;
+-- rollback a savepoint: this should count 4 inserts and have 2
+-- live tuples after commit (and 2 dead ones due to aborted subxact)
+BEGIN;
+INSERT INTO trunc_stats_test3 DEFAULT VALUES;
+INSERT INTO trunc_stats_test3 DEFAULT VALUES;
+SAVEPOINT p1;
+INSERT INTO trunc_stats_test3 DEFAULT VALUES;
+INSERT INTO trunc_stats_test3 DEFAULT VALUES;
+TRUNCATE trunc_stats_test3;
+INSERT INTO trunc_stats_test3 DEFAULT VALUES;
+ROLLBACK TO SAVEPOINT p1;
+COMMIT;
+-- rollback a truncate: this should count 2 inserts and produce 2 dead tuples
+BEGIN;
+INSERT INTO trunc_stats_test4 DEFAULT VALUES;
+INSERT INTO trunc_stats_test4 DEFAULT VALUES;
+TRUNCATE trunc_stats_test4;
+INSERT INTO trunc_stats_test4 DEFAULT VALUES;
+ROLLBACK;
+-- do a seqscan
+SELECT count(*) FROM tenk2;
+ count 
+-------
+ 10000
+(1 row)
+
+-- do an indexscan
+-- make sure it is not a bitmap scan, which might skip fetching heap tuples
+SET enable_bitmapscan TO off;
+SELECT count(*) FROM tenk2 WHERE unique1 = 1;
+ count 
+-------
+     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 
+----------------
+ 
+(1 row)
+
+-- check effects
+SELECT relname, n_tup_ins, n_tup_upd, n_tup_del, n_live_tup, n_dead_tup
+  FROM pg_stat_user_tables
+ WHERE relname like 'trunc_stats_test%' order by relname;
+      relname      | n_tup_ins | n_tup_upd | n_tup_del | n_live_tup | n_dead_tup 
+-------------------+-----------+-----------+-----------+------------+------------
+ trunc_stats_test  |         3 |         0 |         0 |          0 |          0
+ trunc_stats_test1 |         4 |         2 |         1 |          1 |          0
+ trunc_stats_test2 |         1 |         0 |         0 |          1 |          0
+ trunc_stats_test3 |         4 |         0 |         0 |          2 |          2
+ trunc_stats_test4 |         2 |         0 |         0 |          0 |          2
+(5 rows)
+
+SELECT st.seq_scan >= pr.seq_scan + 1,
+       st.seq_tup_read >= pr.seq_tup_read + cl.reltuples,
+       st.idx_scan >= pr.idx_scan + 1,
+       st.idx_tup_fetch >= pr.idx_tup_fetch + 1
+  FROM pg_stat_user_tables AS st, pg_class AS cl, prevstats AS pr
+ WHERE st.relname='tenk2' AND cl.relname='tenk2';
+ ?column? | ?column? | ?column? | ?column? 
+----------+----------+----------+----------
+ t        | t        | t        | t
+(1 row)
+
+SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages,
+       st.idx_blks_read + st.idx_blks_hit >= pr.idx_blks + 1
+  FROM pg_statio_user_tables AS st, pg_class AS cl, prevstats AS pr
+ WHERE st.relname='tenk2' AND cl.relname='tenk2';
+ ?column? | ?column? 
+----------+----------
+ t        | t
+(1 row)
+
+SELECT pr.snap_ts < pg_stat_get_snapshot_timestamp() as snapshot_newer
+FROM prevstats AS pr;
+ snapshot_newer 
+----------------
+ t
+(1 row)
+
+DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
+DROP TABLE prevstats;
+-- ensure that stats accessors handle NULL input correctly
+SELECT pg_stat_get_replication_slot(NULL);
+ pg_stat_get_replication_slot 
+------------------------------
+ 
+(1 row)
+
+-- End of Stats Test