Обсуждение: pgsql: Harden pg_filenode_relation test against concurrent DROP TABLE.

Harden pg_filenode_relation test against concurrent DROP TABLE.

Per buildfarm member prairiedog.  Back-patch to 9.4, where the test was
introduced.

Reviewed by Tom Lane.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/f3fdd257a430ff581090740570af9f266bb893e3

Modified Files
--------------
src/test/regress/expected/alter_table.out |   11 ++++++++---
src/test/regress/sql/alter_table.sql      |   12 +++++++++---
2 files changed, 17 insertions(+), 6 deletions(-)