On Wed, May 12, 2021 at 9:08 AM Amit Kapila <amit.kapil...@gmail.com> wrote:
>
> On Wed, May 12, 2021 at 7:53 AM Amit Kapila <amit.kapil...@gmail.com> wrote:
> >
> > On Wed, May 12, 2021 at 4:00 AM Masahiko Sawada <sawada.m...@gmail.com>
> > wrote:
> > >
> > > Ugh, since by commit 592f00f8de we send slot stats every after
> > > spil/stream it’s possible that we report slot stats that have non-zero
> > > counters for spill_bytes/txns and zeroes for total_bytes/txns. It
> > > seems to me it’s legitimate that the slot stats view shows non-zero
> > > values for spill_bytes/txns and zero values for total_bytes/txns
> > > during decoding a large transaction. So I think we can fix the test
> > > script so that it checks only spill_bytes/txns when checking spilled
> > > transactions.
> > >
> >
> > Your analysis and fix look correct to me.
> >
>
> I think the part of the test that tests the stats after resetting it
> might give different results. This can happen because in the previous
> test we spill multiple times (spill_count is 12 in my testing) and it
> is possible that some of the spill stats messages is received by stats
> collector after the reset message. If this theory is correct then it
> better that we remove the test for reset stats and the test after it
> "decode and check stats again.". This is not directly related to your
> patch or buildfarm failure but I guess this can happen and we might
> see such a failure in future.
I agree with your analysis to remove that test. Attached patch has the
changes for the same.
Regards,
Vignesh
diff --git a/contrib/test_decoding/expected/stats.out b/contrib/test_decoding/expected/stats.out
index 7d174ee8d2..206c0a126e 100644
--- a/contrib/test_decoding/expected/stats.out
+++ b/contrib/test_decoding/expected/stats.out
@@ -111,48 +111,10 @@ SELECT wait_for_decode_stats(false, true);
(1 row)
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
- slot_name | spill_txns | spill_count | total_txns | total_bytes
------------------------+------------+-------------+------------+-------------
- regression_slot_stats | t | t | t | t
-(1 row)
-
--- reset the slot stats, and wait for stats collector to reset
-SELECT pg_stat_reset_replication_slot('regression_slot_stats');
- pg_stat_reset_replication_slot
---------------------------------
-
-(1 row)
-
-SELECT wait_for_decode_stats(true, true);
- wait_for_decode_stats
------------------------
-
-(1 row)
-
-SELECT slot_name, spill_txns, spill_count, total_txns, total_bytes FROM pg_stat_replication_slots;
- slot_name | spill_txns | spill_count | total_txns | total_bytes
------------------------+------------+-------------+------------+-------------
- regression_slot_stats | 0 | 0 | 0 | 0
-(1 row)
-
--- decode and check stats again.
-SELECT count(*) FROM pg_logical_slot_peek_changes('regression_slot_stats', NULL, NULL, 'skip-empty-xacts', '1');
- count
--------
- 5002
-(1 row)
-
-SELECT wait_for_decode_stats(false, true);
- wait_for_decode_stats
------------------------
-
-(1 row)
-
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
- slot_name | spill_txns | spill_count | total_txns | total_bytes
------------------------+------------+-------------+------------+-------------
- regression_slot_stats | t | t | t | t
+SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count FROM pg_stat_replication_slots;
+ slot_name | spill_txns | spill_count
+-----------------------+------------+-------------
+ regression_slot_stats | t | t
(1 row)
-- Ensure stats can be repeatedly accessed using the same stats snapshot. See
diff --git a/contrib/test_decoding/sql/stats.sql b/contrib/test_decoding/sql/stats.sql
index 263568b00c..67462ca27f 100644
--- a/contrib/test_decoding/sql/stats.sql
+++ b/contrib/test_decoding/sql/stats.sql
@@ -73,17 +73,7 @@ SELECT count(*) FROM pg_logical_slot_peek_changes('regression_slot_stats', NULL,
-- exact stats count as that can vary if any background transaction (say by
-- autovacuum) happens in parallel to the main transaction.
SELECT wait_for_decode_stats(false, true);
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
-
--- reset the slot stats, and wait for stats collector to reset
-SELECT pg_stat_reset_replication_slot('regression_slot_stats');
-SELECT wait_for_decode_stats(true, true);
-SELECT slot_name, spill_txns, spill_count, total_txns, total_bytes FROM pg_stat_replication_slots;
-
--- decode and check stats again.
-SELECT count(*) FROM pg_logical_slot_peek_changes('regression_slot_stats', NULL, NULL, 'skip-empty-xacts', '1');
-SELECT wait_for_decode_stats(false, true);
-SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
+SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count FROM pg_stat_replication_slots;
-- Ensure stats can be repeatedly accessed using the same stats snapshot. See
-- https://postgr.es/m/20210317230447.c7uc4g3vbs4wi32i%40alap3.anarazel.de
