Geo: Allow configuration of sslcompression option
We've seen on GitLab.com enabling SSL compression (https://www.postgresql.org/docs/9.6/static/libpq-connect.html), which is the default behavior, may be causing replication lag in https://gitlab.com/gitlab-com/infrastructure/issues/4125.
This is particularly important in Geo because we mandate SSL connections between the primary and the secondary.
Note that you can have SSL on but disable SSL compression, as other open source software has done (https://github.com/requests/requests/issues/1857).
We should probably:
- Set
sslcompression=0
inrecovery.conf
by default - Allow users to enable this if they really want