postgres_fdw: Fix handling of abort-cleanup-failed connections. As connections that failed abort cleanup can't safely be further used, if a remote query tries to get such a connection, we reject it. Previously, this rejection involved dropping the connection if it was open, without accounting for the possibility of open cursors using it, causing a server crash when such an open cursor tried to use an already-dropped connection, as a cursor-handling function (create_cursor, fetch_more_data, or close_cursor) was called on a freed PGconn. To fix, delay dropping failed connections until abort cleanup of the main transaction, to ensure open cursors using such a connection can safely refer to the PGconn for it.
Oversight in commit 8bf58c0d9. Reported-by: Zhibai Song <[email protected]> Diagnosed-by: Zhibai Song <[email protected]> Author: Etsuro Fujita <[email protected]> Reviewed-by: Michael Paquier <[email protected]> Reviewed-by: Chao Li <[email protected]> Reviewed-by: Matheus Alcantara <[email protected]> Discussion: https://postgr.es/m/CAPmGK176y6JP017-Cn%2BhS9CEJx_6iVhRoYbAqzuLU4d8-XPPNg%40mail.gmail.com Backpatch-through: 14 Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/af8f9248fbe72f8c19f4f20daf38495afdd0a26b Modified Files -------------- contrib/postgres_fdw/connection.c | 10 ++-- contrib/postgres_fdw/expected/postgres_fdw.out | 76 ++++++++++++++++++++++++++ contrib/postgres_fdw/sql/postgres_fdw.sql | 51 +++++++++++++++++ 3 files changed, 133 insertions(+), 4 deletions(-)
