X-Git-Url: https://git.openstreetmap.org./rails.git/blobdiff_plain/afe679349fb7139f5cff5830f45e4b8214732812..4b2d6436cee11c0b3d751ef15cace053e26fbf3d:/CONFIGURE.md

diff --git a/CONFIGURE.md b/CONFIGURE.md
index a78162b67..278d1c398 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 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 want to use diff replication then you might want to consider installing the shared library special SQL functions for the `xid_to_int4` function. A pure SQL version is available, but may become a performance issue on large databases with a high rate of changes. Note that you will need a version of PostgreSQL < 9.6 (yes, _less than_) to use `xid` indexing, whether pure SQL or shared library.
 * 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.