[pgpool-committers: 4061] pgpool: Deal with PostgreSQL 10 in streaming replication delay checking

[Tatsuo Ishii]

Deal with PostgreSQL 10 in streaming replication delay checking.

From PostgreSQL 10 or later, some built in function names which are
used in streaming replication delay checking are changed. To deal with
this, get server_version_num from backend to change the calling
functions and cache them. Using 'S' message to extract the server
version string while connecting backend could be an idea, but
unfortunately connecting function used in streaming replication delay
checking does not handle 'S' parameter. Also converting from the
server version string to the server_version_num can be backend
dependent, so to extract the server_version_num would be safer.

Branch
------
V3_6_STABLE

Details
-------
https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=6e6b02203da3425a7fbb8cf6c045efab2fe804b8

Modified Files
--------------
src/streaming_replication/pool_worker_child.c | 118 +++++++++++++++++++-------
1 file changed, 85 insertions(+), 33 deletions(-)