package tiger_geocoder as a PostgreSQL extension

[robe]

Right now this is the only part that can't be installed as an extension. Part of the reason for that is that the upgrade script actually changes user data though the raw install script would be fairly trivial to have as an extension. There isn't much point though if it can't be upgraded easily.

[robe]

Started work on this at r10383

[robe]

This is functioning as of r10934. So now it is possible to

CREATE EXTENSION postgis_tiger_geocoder;

And if you have latest 2.1.0 installed without using an extension convert to extension model with

CREATE EXTENSION postgis_tiger_geocoder FROM unpackaged;

I still need to stress test, update the docs, and also implement the

UPDATE EXTENSION logic before I can consider this closed.

[robe]

I've updated the docs.  http://postgis.net/docs/manual-dev/postgis_installation.html#install_tiger_geocoder_extension

Nice thing about extensions is that if you forget the dependencies it won't let you install and will warn you with a "extension requires fuzzystrmatch" etc.

I'm going to close this out and create a separate ticket to create an upgrade path. That will take me more time to write up and test.