X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/1d7e4a4c467c0efde921955bb7e1337ea48df622..ced8ac86abac9c9efad7b74a0efe2e252ddc59af:/INSTALL.md

diff --git a/INSTALL.md b/INSTALL.md
index 2b1b4b5de..641d1160a 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -31,8 +31,8 @@ sudo apt-get update
 sudo apt-get install ruby2.5 libruby2.5 ruby2.5-dev bundler \
                      libmagickwand-dev libxml2-dev libxslt1-dev nodejs \
                      apache2 apache2-dev build-essential git-core phantomjs \
-                     postgresql postgresql-contrib libpq-dev postgresql-server-dev-all \
-                     libsasl2-dev imagemagick libffi-dev libgd-dev libarchive-dev libbz2-dev
+                     postgresql postgresql-contrib libpq-dev libsasl2-dev \
+                     imagemagick libffi-dev libgd-dev libarchive-dev libbz2-dev
 sudo gem2.5 install bundler
 ```
 
@@ -46,7 +46,7 @@ For Fedora, you can install the minimum requirements with:
 sudo dnf install ruby ruby-devel rubygem-rdoc rubygem-bundler rubygems \
                  libxml2-devel js \
                  gcc gcc-c++ git \
-                 postgresql postgresql-server postgresql-contrib postgresql-devel \
+                 postgresql postgresql-server postgresql-contrib \
                  perl-podlators ImageMagick libffi-devel gd-devel libarchive-devel \
                  bzip2-devel nodejs-yarn
 ```
@@ -174,20 +174,12 @@ psql -d openstreetmap -c "CREATE EXTENSION btree_gist"
 
 ### PostgreSQL Functions
 
-We need to install special functions into the PostgreSQL databases, and these are provided by a library that needs compiling first.
+There are special database functions required by a (little-used) API call, the migrations and diff replication. The former two are provided as *either* pure SQL functions or a compiled shared library. It is recommended that you start with the pure SQL versions, as described below, and only install the compiled shared library if you are running a production server making a lot of `/changes` API calls or need the diff replication functionality.
 
-```
-cd db/functions
-make libpgosm.so
-cd ../..
-```
-
-Then we create the functions within each database. We're using `pwd` to substitute in the current working directory, since PostgreSQL needs the full path.
+If you aren't sure which you need, install the SQL version below.
 
 ```
-psql -d openstreetmap -c "CREATE FUNCTION maptile_for_point(int8, int8, int4) RETURNS int4 AS '`pwd`/db/functions/libpgosm', 'maptile_for_point' LANGUAGE C STRICT"
-psql -d openstreetmap -c "CREATE FUNCTION tile_for_point(int4, int4) RETURNS int8 AS '`pwd`/db/functions/libpgosm', 'tile_for_point' LANGUAGE C STRICT"
-psql -d openstreetmap -c "CREATE FUNCTION xid_to_int4(xid) RETURNS int4 AS '`pwd`/db/functions/libpgosm', 'xid_to_int4' LANGUAGE C STRICT"
+psql -d openstreetmap -f db/functions/functions.sql
 ```
 
 ### Database structure
@@ -225,3 +217,42 @@ Note that the OSM map tiles you see aren't created from your local database - th
 # Configuration
 
 After installing this software, you may need to carry out some [configuration steps](CONFIGURE.md), depending on your tasks.
+
+# Installing compiled shared library database functions
+
+You probably only need to do this if you are running a large, production instance of openstreetmap-website.
+
+Before installing the functions, it's necessary to install the PostgreSQL server development packages. On Ubuntu this means:
+
+```
+sudo apt-get install postgresql-server-dev-all
+```
+
+On Fedora:
+
+```
+sudo dnf install postgresql-devel
+```
+
+The library then needs compiling.
+
+```
+cd db/functions
+make libpgosm.so
+cd ../..
+```
+
+If you previously installed the SQL versions of these functions, we'll need to delete those before adding the new ones:
+
+```
+psql -d openstreetmap -c "DROP FUNCTION IF EXISTS maptile_for_point"
+psql -d openstreetmap -c "DROP FUNCTION IF EXISTS tile_for_point"
+```
+
+Then we create the functions within each database. We're using `pwd` to substitute in the current working directory, since PostgreSQL needs the full path.
+
+```
+psql -d openstreetmap -c "CREATE FUNCTION maptile_for_point(int8, int8, int4) RETURNS int4 AS '`pwd`/db/functions/libpgosm', 'maptile_for_point' LANGUAGE C STRICT"
+psql -d openstreetmap -c "CREATE FUNCTION tile_for_point(int4, int4) RETURNS int8 AS '`pwd`/db/functions/libpgosm', 'tile_for_point' LANGUAGE C STRICT"
+psql -d openstreetmap -c "CREATE FUNCTION xid_to_int4(xid) RETURNS int4 AS '`pwd`/db/functions/libpgosm', 'xid_to_int4' LANGUAGE C STRICT"
+```