postgres_fdw: stabilize terminated-connection regression tests The regression test for postgres_fdw_get_connections(true) assumed that a terminated remote connection would still remain visible in the FDW connection cache long enough to be reported as closed with a nonzero remote_backend_pid.
That assumption is not always valid. postgres_fdw_get_connections() reports only entries that are still present in ConnectionHash, while pgfdw_inval_callback() may immediately discard an idle cached connection (xact_depth == 0) when a relevant invalidation arrives. In CI, that can happen between terminating the remote backend and querying postgres_fdw_get_connections(true), causing the function to return no rows. Adjust the idle-connection test to accept either outcome: if the cache entry is still present, verify that it reports the expected server name, closed status, and nonzero remote backend PID; otherwise treat zero rows as a legitimate result. To preserve coverage of the terminated-backend reporting path, add a separate check inside an explicit transaction. In that case, concurrent invalidation may mark the connection invalid but cannot discard it before transaction end, so postgres_fdw_get_connections(true) should still report the terminated connection as in-use, closed, and associated with a nonzero remote backend PID. Backpatch to v18, where the affected postgres_fdw_get_connections(true) test was introduced. Reported-by: Robert Haas <[email protected]> Author: Fujii Masao <[email protected]> Reviewed-by: Robert Haas <[email protected]> Reviewed-by: Daniel Gustafsson <[email protected]> Discussion: https://postgr.es/m/ca+tgmoax3chxhsm9oidn4f-xiu16y8q2w8t5dtnfic1zoo2...@mail.gmail.com Backpatch-through: 18 Branch ------ REL_19_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/ee8f123da72d9e23e35848bfe3c2f49c02d7756c Modified Files -------------- contrib/postgres_fdw/expected/postgres_fdw.out | 60 ++++++++++++++++++++++---- contrib/postgres_fdw/sql/postgres_fdw.sql | 40 ++++++++++++++--- 2 files changed, 87 insertions(+), 13 deletions(-)
