pgsql: Zero padding in replication origin's checkpointed on disk-state.

Zero padding in replication origin's checkpointed on disk-state.

This seems to be largely cosmetic, avoiding valgrind bleats and the
like. The uninitialized padding influences the CRC of the on-disk
entry, but because it's also used when verifying the CRC, that doesn't
cause spurious failures. Backpatch nonetheless.

It's a bit unfortunate that contrib/test_decoding/sql/replorigin.sql
doesn't exercise the checkpoint path, but checkpoints are fairly
expensive on weaker machines, and we'd have to stop/start for that to
be meaningful.

Author: Andres Freund
Discussion: https://postgr.es/m/20170422183123.w2jgiuxtts7qrqaq@alap3.anarazel.de
Backpatch: 9.5, where replication origins were introduced

Branch
------
REL9_5_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/81ff04deda21e016e0e1d4ea1755ccb14c47c871

Modified Files
--------------
src/backend/replication/logical/origin.c | 3 +++
1 file changed, 3 insertions(+)