pgsql: Disable autovacuum in 031_recovery_conflict.pl

Disable autovacuum in 031_recovery_conflict.pl

Buildfarm members adder and drongo failed to observe the expected relation
lock wait in the startup deadlock test. In adder's failure, autovacuum
pruned dead rows before the test's explicit VACUUM FREEZE, canceling the
standby backend too early and releasing the relation lock wait before the
test could observe it.

Fix this by disabling autovacuum for the test node, leaving the explicit
VACUUM commands in control of when pruning occurs. This also prevents
auto-analyze workers on other relations from holding back xmin and
interfering with the snapshot conflict test.

Backpatch to v17, where this test is enabled.

Reported-by: Alexander Lakhin <exclusion(at)gmail(dot)com>
Author: Ayush Tiwari <ayushtiwari(dot)slg01(at)gmail(dot)com>
Reviewed-by: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Discussion: https://postgr.es/m/421c0aee-84c8-4c07-b4b9-263095479755%40gmail.com
Discussion: https://postgr.es/m/714729ea-f536-0faf-353b-cbd5c8f241ea%40gmail.com
Backpatch-through: 17

Branch
------
REL_19_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/81083d7b4fbf33ceb58b1f8849124b779edf97bc

Modified Files
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src/test/recovery/t/031_recovery_conflict.pl | 3 +++
1 file changed, 3 insertions(+)