Обсуждение: pgsql: Fix race in test of pg_switch_wal().

Fix race in test of pg_switch_wal().

The test failed when something added WAL between pg_switch_wal() and
pg_current_wal_lsn(), seen on buildfarm members hornet and sungazer.
Fix v10, v9.6 and v9.5 by making this code mirror its v13+ counterpart.
v12 and v11 lack a counterpart.

Branch
------
REL9_6_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/e09391a0a042a631de05faa195aea86acc66ba43

Modified Files
--------------
src/test/recovery/t/020_archive_status.pl | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)