pgsql: Prevent non-streaming replication connections from being selecte

Prevent non-streaming replication connections from being selected sync slave

This prevents a pg_basebackup backup session that just does a base
backup (no xlog involved at all) from becoming the synchronous slave
and thus blocking all access while it runs.

Also fixes the problem when a higher priority slave shows up it would
become the sync standby before it has reached the STREAMING state, by
making sure we can only switch to a walsender that's actually STREAMING.

Fujii Masao

Branch
------
REL9_1_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/580b94168e2218a2a32d6792139d51c63104b2c2

Modified Files
--------------
src/backend/replication/syncrep.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)