Ensure that num_sync is greater than zero in synchronous_standby_names.
Previously num_sync could be set to zero and this setting caused
an assertion failure. This means that multiple synchronous standbys
code should assume that num_sync is greater than zero.
Also setting num_sync to zero is nonsense because it's basically
the configuration for synchronous replication. If users want not to
make transaction commits wait for any standbys,
synchronous_standby_names should be emptied to disable synchronous
replication instead of setting num_sync to zero.
This patch forbids users from setting num_sync to zero in
synchronous_standby_names. If zero is specified, an error will
happen during processing the parameter settings.
Back-patch to 9.6 where multiple synchronous standbys feature was added.
Patch by me. Reviewed by Tom Lane.
Discussion: <CAHGQGwHWB3izc6cXuFLh5kOcAbFXaRhhgwd-X5PeN9TEjxqXwg@mail.gmail.com>
Branch
------
REL9_6_STABLE
Details
-------
http://git.postgresql.org/pg/commitdiff/6c75fb6b3dbeda4dac19cee8f2d5cc7f38f362ee
Modified Files
--------------
src/backend/replication/syncrep.c | 7 +++++++
1 file changed, 7 insertions(+)
