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Fix flakyness in isolation_insert_vs_vacuum (#6589) 

Sometimes our `isolation_insert_vs_vacuum` test would fail like this.

```diff
 step s2-vacuum-analyze:
     VACUUM ANALYZE test_insert_vacuum;
-
+ <waiting ...>
 step s1-commit:
     COMMIT;

+step s2-vacuum-analyze: <... completed>

```

The reason seems to be that VACUUM ANALYZE tries to take some locks that
conflict with the other transaction, but these locks somehow get
released or VACUUM ANALYZE stops waiting for them. This is somewhat
expected since VACUUM has some special locking logic.

To solve the flakyness we now trigger VACUUM ANALYZE to always report as
blocking and after that we wait explicitly wait for it to complete. This
is done
like is suggested by the flaky test tips from postgres: 

c68a183990/src/test/isolation/README (L152)

I've confirmed that this fixes the issue suing our flaky-test-debugging
CI workflow.
fix-issue-wit-6412-v2
Jelte Fennema 2023-01-02 16:51:58 +01:00 committed by GitHub
parent 0c74e4cc0f
commit f56904fe04
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2 changed files with 11 additions and 3 deletions
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6
src/test/regress/expected/isolation_insert_vs_vacuum.out
View File

@ -1,6 +1,6 @@
Parsed test spec with 2 sessions
starting permutation: s1-begin s1-insert s2-vacuum-analyze s1-commit
starting permutation: s1-begin s1-insert s2-vacuum-analyze s2-wait s1-commit
create_distributed_table
---------------------------------------------------------------------
@ -14,7 +14,9 @@ step s1-insert:
step s2-vacuum-analyze:
VACUUM ANALYZE test_insert_vacuum;
<waiting ...>
step s2-vacuum-analyze: <... completed>
step s2-wait:
step s1-commit:
COMMIT;

8
src/test/regress/spec/isolation_insert_vs_vacuum.spec
View File

@ -39,8 +39,14 @@ step "s2-vacuum-full"
VACUUM FULL test_insert_vacuum;
}
step "s2-wait" {}
// INSERT and VACUUM ANALYZE should not block each other.
permutation "s1-begin" "s1-insert" "s2-vacuum-analyze" "s1-commit"
// vacuum analyze sometimes gets randomly blocked temporarily, but this is
// resolved automatically. To avoid flaky output, we always trigger a
// <waiting...> message using (*) and then we wait until vacuum analyze
// actually completes.
permutation "s1-begin" "s1-insert" "s2-vacuum-analyze"(*) "s2-wait" "s1-commit"
// INSERT and VACUUM FULL should block each other.
permutation "s1-begin" "s1-insert" "s2-vacuum-full" "s1-commit"