postgrespro.git / summary / log / commit / refs
commit f03a9ca4366d064d89b7cf7ed75d4e43f2ed0667
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue May 21 16:23:16 2019 +0000
Insert temporary debugging output in regression tests.
We're seeing occasional instability in the plans generated for
parallel queries on the "a_star" table hierarchy. This suggests
that something is changing the planner's stats for those tables,
but that should not be happening within a regression test run.
To try to gather some information about what's happening, insert
additional queries to check the basic page/tuple counts for these
tables, as well as whether any vacuums or analyzes have happened
on them. (We expect that only the database-wide VACUUM in
sanity_check.sql will have touched them.)
I added the probes not only in select_parallel.sql itself, but
also in stats.sql, bearing in mind that the stats collector's
lag may prevent the initial query from reporting current truth.
If any extra vacuum/analyze has happened, the recheck in stats.sql
definitely ought to see it.
This commit can be reverted once we figure out what's going on.
Per suggestion from David Rowley, though I changed the queries around.
Discussion: https://postgr.es/m/CA+hUKG+0CxrKRWRMf5ymN3gm+BECHna2B-q1w8onKBep4HasUw@mail.gmail.com
src/test/regress/expected/select_parallel.out | 27 +++++++++++++++++++++++++++
src/test/regress/expected/stats.out | 27 +++++++++++++++++++++++++++
src/test/regress/sql/select_parallel.sql | 8 ++++++++
src/test/regress/sql/stats.sql | 8 ++++++++
4 files changed, 70 insertions(+)
diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index 0eca76cb41..9775cc898c 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -89,6 +89,33 @@ select round(avg(aa)), sum(aa) from a_star a3;
14 | 355
(1 row)
+-- Temporary hack to investigate whether extra vacuum/analyze is happening
+select relname, relpages, reltuples
+from pg_class
+where relname like '__star' order by relname;
+ relname | relpages | reltuples
+---------+----------+-----------
+ a_star | 1 | 3
+ b_star | 1 | 4
+ c_star | 1 | 4
+ d_star | 1 | 16
+ e_star | 1 | 7
+ f_star | 1 | 16
+(6 rows)
+
+select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
+from pg_stat_all_tables
+where relname like '__star' order by relname;
+ relname | vacuum_count | analyze_count | autovacuum_count | autoanalyze_count
+---------+--------------+---------------+------------------+-------------------
+ a_star | 1 | 0 | 0 | 0
+ b_star | 1 | 0 | 0 | 0
+ c_star | 1 | 0 | 0 | 0
+ d_star | 1 | 0 | 0 | 0
+ e_star | 1 | 0 | 0 | 0
+ f_star | 1 | 0 | 0 | 0
+(6 rows)
+
-- Disable Parallel Append
alter table a_star reset (parallel_workers);
alter table b_star reset (parallel_workers);
diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index b01e58b98c..61fbf7e41e 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -199,6 +199,33 @@ FROM prevstats AS pr;
t
(1 row)
+-- Temporary hack to investigate whether extra vacuum/analyze is happening
+select relname, relpages, reltuples
+from pg_class
+where relname like '__star' order by relname;
+ relname | relpages | reltuples
+---------+----------+-----------
+ a_star | 1 | 3
+ b_star | 1 | 4
+ c_star | 1 | 4
+ d_star | 1 | 16
+ e_star | 1 | 7
+ f_star | 1 | 16
+(6 rows)
+
+select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
+from pg_stat_all_tables
+where relname like '__star' order by relname;
+ relname | vacuum_count | analyze_count | autovacuum_count | autoanalyze_count
+---------+--------------+---------------+------------------+-------------------
+ a_star | 1 | 0 | 0 | 0
+ b_star | 1 | 0 | 0 | 0
+ c_star | 1 | 0 | 0 | 0
+ d_star | 1 | 0 | 0 | 0
+ e_star | 1 | 0 | 0 | 0
+ f_star | 1 | 0 | 0 | 0
+(6 rows)
+
DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
DROP TABLE prevstats;
-- End of Stats Test
diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql
index 03c056b8b7..f96812b550 100644
--- a/src/test/regress/sql/select_parallel.sql
+++ b/src/test/regress/sql/select_parallel.sql
@@ -36,6 +36,14 @@ explain (costs off)
select round(avg(aa)), sum(aa) from a_star;
select round(avg(aa)), sum(aa) from a_star a3;
+-- Temporary hack to investigate whether extra vacuum/analyze is happening
+select relname, relpages, reltuples
+from pg_class
+where relname like '__star' order by relname;
+select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
+from pg_stat_all_tables
+where relname like '__star' order by relname;
+
-- Disable Parallel Append
alter table a_star reset (parallel_workers);
alter table b_star reset (parallel_workers);
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index feaaee6326..9defd4b7a9 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -174,6 +174,14 @@ SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages,
SELECT pr.snap_ts < pg_stat_get_snapshot_timestamp() as snapshot_newer
FROM prevstats AS pr;
+-- Temporary hack to investigate whether extra vacuum/analyze is happening
+select relname, relpages, reltuples
+from pg_class
+where relname like '__star' order by relname;
+select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
+from pg_stat_all_tables
+where relname like '__star' order by relname;
+
DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
DROP TABLE prevstats;
-- End of Stats Test
[parent: 1171d7d58545]