X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/2423d869146fa513caf1eb5c6c0a452235f70e05..7fb5bcaf3f9775ee1de185efb3164a100ecccdc3:/CONFIGURE.md

diff --git a/CONFIGURE.md b/CONFIGURE.md
index 42f65b5c1..a78162b67 100644
--- a/CONFIGURE.md
+++ b/CONFIGURE.md
@@ -131,5 +131,5 @@ If you want to deploy The Rails Port for production use, you'll need to make a f
 * The included version of the GPX importer is slow and/or completely inoperable. You should consider using [the high-speed GPX importer](https://git.openstreetmap.org/gpx-import.git/).
 * Make sure you generate the i18n files and precompile the production assets: `RAILS_ENV=production rake i18n:js:export assets:precompile`
 * Make sure the web server user as well as the rails user can read, write and create directories in `tmp/`.
-* If you want to use diff replication then you will need to install the shared library versions of the special SQL functions (see the bottom of [INSTALL.md](INSTALL.md)).
+* If you want to use diff replication then you will need to install the shared library special SQL functions for the `xid_to_int4` function, for which there is no pure SQL alternative. (See the bottom of [INSTALL.md](INSTALL.md))
 * If you expect to serve a lot of `/changes` API calls, then you might also want to install the shared library versions of the SQL functions.