Installcheck in a loop eventually fails

[a-masterov]

Hello!

If we run the installcheck in a loop, e.g.

CNT=0
while make installcheck
do
    let CNT++
done
echo Test failed on run $CNT

it eventually failed.

Errors can look like

diff -U3 /wal2json-wal2json_2_6/expected/include_timestamp.out /wal2json-wal2json_2_6/results/include_timestamp.out
--- /wal2json-wal2json_2_6/expected/include_timestamp.out       2024-04-25 01:02:38.000000000 +0000
+++ /wal2json-wal2json_2_6/results/include_timestamp.out        2024-05-20 10:44:22.432449005 +0000
@@ -15,7 +15,7 @@
 SELECT count(*) = 1, count(distinct ((data::json)->'timestamp')::text) = 1 FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'format-version', '1', 'include-timestamp', '1');
  ?column? | ?column? 
 ----------+----------
- t        | t
+ f        | f
 (1 row)
 
 -- Two rows should have two records and two timestamps
@@ -24,7 +24,7 @@
 SELECT count(*) = 2, count(distinct ((data::json)->'timestamp')::text) = 2 FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'format-version', '1', 'include-timestamp', '1');
  ?column? | ?column? 
 ----------+----------
- t        | t
+ f        | f
 (1 row)
 
 -- Two rows in one transaction should have one record and one timestamp
@@ -32,7 +32,7 @@
 SELECT count(*) = 1, count(distinct ((data::json)->'timestamp')::text) = 1 FROM pg_logical_slot_get_changes('regression_slot', NULL, NULL, 'format-version', '1', 'include-timestamp', '1');
  ?column? | ?column? 
 ----------+----------
- t        | t
+ f        | f
 (1 row)
 
 SELECT 'stop' FROM pg_drop_replication_slot('regression_slot');

They occur randomly in different SQL files.
Maybe it happens due to background maintenance processes like autovacuum