Merge pull request #1733 from krahulreddy/whitespaces-considered-as-single-space

[nominatim.git] / docs / admin / Import-and-Update.md

diff --git a/docs/admin/Import-and-Update.md b/docs/admin/Import-and-Update.md
index 26ed9eb94788ee7b776f959b377cede5284b97bf..c80b54a047b28a0883a52f84f4796d0582008c3b 100644 (file)
--- a/docs/admin/Import-and-Update.md
+++ b/docs/admin/Import-and-Update.md
@@ -1,9 +1,11 @@
+# Importing and Updating the Database
+

 The following instructions explain how to create a Nominatim database
 from an OSM planet file and how to keep the database up to date. It
 is assumed that you have already successfully installed the Nominatim
 software itself, if not return to the [installation page](Installation.md).
 
 The following instructions explain how to create a Nominatim database
 from an OSM planet file and how to keep the database up to date. It
 is assumed that you have already successfully installed the Nominatim
 software itself, if not return to the [installation page](Installation.md).
 

-# Configuration setup in settings/local.php
+## Configuration setup in settings/local.php

 
 The Nominatim server can be customized via the file `settings/local.php`
 in the build directory. Note that this is a PHP file, so it must always
 
 The Nominatim server can be customized via the file `settings/local.php`
 in the build directory. Note that this is a PHP file, so it must always


@@ -16,7 +18,7 @@ without any leading spaces.
 There are lots of configuration settings you can tweak. Have a look
 at `settings/default.php` for a full list. Most should have a sensible default.
 
 There are lots of configuration settings you can tweak. Have a look
 at `settings/default.php` for a full list. Most should have a sensible default.
 

-### Flatnode files
+#### Flatnode files

 
 If you plan to import a large dataset (e.g. Europe, North America, planet),
 you should also enable flatnode storage of node locations. With this
 
 If you plan to import a large dataset (e.g. Europe, North America, planet),
 you should also enable flatnode storage of node locations. With this


@@ -27,56 +29,178 @@ Add to your `settings/local.php`:
     @define('CONST_Osm2pgsql_Flatnode_File', '/path/to/flatnode.file');
 
 Replace the second part with a suitable path on your system and make sure
     @define('CONST_Osm2pgsql_Flatnode_File', '/path/to/flatnode.file');
 
 Replace the second part with a suitable path on your system and make sure

-the directory exists. There should be at least 40GB of free space.
+the directory exists. There should be at least 64GB of free space.

 
 

-# Downloading additional data
+## Downloading additional data

 
 

-## Wikipedia rankings
+### Wikipedia/Wikidata rankings

 
 Wikipedia can be used as an optional auxiliary data source to help indicate
 
 Wikipedia can be used as an optional auxiliary data source to help indicate

-the importance of osm features. Nominatim will work without this information
+the importance of OSM features. Nominatim will work without this information

 but it will improve the quality of the results if this is installed.
 This data is available as a binary download:
 
     cd $NOMINATIM_SOURCE_DIR/data
 but it will improve the quality of the results if this is installed.
 This data is available as a binary download:
 
     cd $NOMINATIM_SOURCE_DIR/data

-    wget https://www.nominatim.org/data/wikipedia_article.sql.bin
-    wget https://www.nominatim.org/data/wikipedia_redirect.sql.bin
+    wget https://www.nominatim.org/data/wikimedia-importance.sql.gz

 
 

-Combined the 2 files are around 1.5GB and add around 30GB to the install
-size of nominatim. They also increase the install time by an hour or so.
+The file is about 400MB and adds around 4GB to Nominatim database.

 
 

-*NOTE:* you'll need to download the Wikipedia rankings before performing
-the initial import of the data if you want the rankings applied to the
-loaded data.
+!!! tip
+    If you forgot to download the wikipedia rankings, you can also add
+    importances after the import. Download the files, then run
+    `./utils/setup.php --import-wikipedia-articles`
+    and `./utils/update.php --recompute-importance`.

 
 

-## UK postcodes
+### Great Britain, USA postcodes

 
 

-Nominatim can use postcodes from an external source to improve searches that involve a UK postcode. This data can be optionally downloaded: 
+Nominatim can use postcodes from an external source to improve searches that
+involve a GB or US postcode. This data can be optionally downloaded:

 
     cd $NOMINATIM_SOURCE_DIR/data
     wget https://www.nominatim.org/data/gb_postcode_data.sql.gz
 
     cd $NOMINATIM_SOURCE_DIR/data
     wget https://www.nominatim.org/data/gb_postcode_data.sql.gz

+    wget https://www.nominatim.org/data/us_postcode_data.sql.gz
+
+## Choosing the Data to Import
+
+In its default setup Nominatim is configured to import the full OSM data
+set for the entire planet. Such a setup requires a powerful machine with
+at least 64GB of RAM and around 800GB of SSD hard disks. Depending on your
+use case there are various ways to reduce the amount of data imported. This
+section discusses these methods. They can also be combined.
+
+### Using an extract
+
+If you only need geocoding for a smaller region, then precomputed extracts
+are a good way to reduce the database size and import time.
+[Geofabrik](https://download.geofabrik.de) offers extracts for most countries.
+They even have daily updates which can be used with the update process described
+below. There are also
+[other providers for extracts](https://wiki.openstreetmap.org/wiki/Planet.osm#Downloading).
+
+Please be aware that some extracts are not cut exactly along the country
+boundaries. As a result some parts of the boundary may be missing which means
+that Nominatim cannot compute the areas for some administrative areas.
+
+### Dropping Data Required for Dynamic Updates
+
+About half of the data in Nominatim's database is not really used for serving
+the API. It is only there to allow the data to be updated from the latest
+changes from OSM. For many uses these dynamic updates are not really required.
+If you don't plan to apply updates, the dynamic part of the database can be
+safely dropped using the following command:
+
+```
+./utils/setup.php --drop
+```

 
 

+Note that you still need to provide for sufficient disk space for the initial
+import. So this option is particularly interesting if you plan to transfer the
+database or reuse the space later.

 
 

-# Initial import of the data
+### Reverse-only Imports

 
 

-**Important:** first try the import with a small excerpt, for example from
-[Geofabrik](https://download.geofabrik.de).
+If you only want to use the Nominatim database for reverse lookups or
+if you plan to use the installation only for exports to a
+[photon](https://photon.komoot.de/) database, then you can set up a database
+without search indexes. Add `--reverse-only` to your setup command above.

 
 

-Download the data to import and load the data with the following command:
+This saves about 5% of disk space.
+
+### Filtering Imported Data
+
+Nominatim normally sets up a full search database containing administrative
+boundaries, places, streets, addresses and POI data. There are also other
+import styles available which only read selected data:
+
+* **settings/import-admin.style**
+  Only import administrative boundaries and places.
+* **settings/import-street.style**
+  Like the admin style but also adds streets.
+* **settings/import-address.style**
+  Import all data necessary to compute addresses down to house number level.
+* **settings/import-full.style**
+  Default style that also includes points of interest.
+* **settings/import-extratags.style**
+  Like the full style but also adds most of the OSM tags into the extratags
+  column.
+
+The style can be changed with the configuration `CONST_Import_Style`.
+
+To give you an idea of the impact of using the different styles, the table
+below gives rough estimates of the final database size after import of a
+2018 planet and after using the `--drop` option. It also shows the time
+needed for the import on a machine with 64GB RAM, 4 CPUS and SSDs. Note that
+the given sizes are just an estimate meant for comparison of style requirements.
+Your planet import is likely to be larger as the OSM data grows with time.
+
+style     | Import time  |  DB size   |  after drop
+----------|--------------|------------|------------
+admin     |    5h        |  190 GB    |   20 GB
+street    |   42h        |  400 GB    |  180 GB
+address   |   59h        |  500 GB    |  260 GB
+full      |   80h        |  575 GB    |  300 GB
+extratags |   80h        |  585 GB    |  310 GB
+
+You can also customize the styles further. For a description of the
+style format see [the development section](../develop/Import.md).
+
+## Initial import of the data
+
+!!! danger "Important"
+    First try the import with a small extract, for example from
+    [Geofabrik](https://download.geofabrik.de).
+
+Download the data to import and load the data with the following command
+from the build directory:

 
 ```sh
 
 ```sh

-./utils/setup.php --osm-file <data file> --all [--osm2pgsql-cache 28000] 2>&1 | tee setup.log
+./utils/setup.php --osm-file <data file> --all 2>&1 | tee setup.log

 ```
 
 ```
 

-The `--osm2pgsql-cache` parameter is optional but strongly recommended for
-planet imports. It sets the node cache size for the osm2pgsql import part
-(see `-C` parameter in osm2pgsql help). As a rule of thumb, this should be
-about the same size as the file you are importing but never more than
-2/3 of RAM available. If your machine starts swapping reduce the size.
+***Note for full planet imports:*** Even on a perfectly configured machine
+the import of a full planet takes at least 2 days. Once you see messages
+with `Rank .. ETA` appear, the indexing process has started. This part takes
+the most time. There are 30 ranks to process. Rank 26 and 30 are the most complex.
+They take each about a third of the total import time. If you have not reached
+rank 26 after two days of import, it is worth revisiting your system
+configuration as it may not be optimal for the import.
+
+### Notes on memory usage

 
 

-Computing word frequency for search terms can improve the performance of
-forward geocoding in particular under high load as it helps Postgres' query
-planner to make the right decisions. To recompute word counts run:
+In the first step of the import Nominatim uses osm2pgsql to load the OSM data
+into the PostgreSQL database. This step is very demanding in terms of RAM usage.
+osm2pgsql and PostgreSQL are running in parallel at this point. PostgreSQL
+blocks at least the part of RAM that has been configured with the
+`shared_buffers` parameter during [PostgreSQL tuning](Installation#PostgreSQL_tuning)
+and needs some memory on top of that. osm2pgsql needs at least 2GB of RAM for
+its internal data structures, potentially more when it has to process very large
+relations. In addition it needs to maintain a cache for node locations. The size
+of this cache can be configured with the parameter `--osm2pgsql-cache`.
+
+When importing with a flatnode file, it is best to disable the node cache
+completely and leave the memory for the flatnode file. Nominatim will do this
+by default, so you do not need to configure anything in this case.
+
+For imports without a flatnode file, set `--osm2pgsql-cache` approximately to
+the size of the OSM pbf file (in MB) you are importing. Make sure you leave
+enough RAM for PostgreSQL and osm2pgsql as mentioned above. If the system starts
+swapping or you are getting out-of-memory errors, reduce the cache size or
+even consider using a flatnode file.
+
+### Verify import finished
+
+Run this script to verify all required tables and indices got created successfully.
+
+```sh
+./utils/check_import_finished.php
+```
+
+
+## Tuning the database
+
+Accurate word frequency information for search terms helps PostgreSQL's query
+planner to make the right decisions. Recomputing them can improve the performance
+of forward geocoding in particular under high load. To recompute word counts run:

 
 ```sh
 ./utils/update.php --recompute-word-counts
 
 ```sh
 ./utils/update.php --recompute-word-counts


@@ -94,78 +218,61 @@ you also need to enable these key phrases like this:
     ./utils/specialphrases.php --wiki-import > specialphrases.sql
     psql -d nominatim -f specialphrases.sql
 
     ./utils/specialphrases.php --wiki-import > specialphrases.sql
     psql -d nominatim -f specialphrases.sql
 

-Note that this command downloads the phrases from the wiki link above.
-
+Note that this command downloads the phrases from the wiki link above. You
+need internet access for the step.

 
 

-# Installing Tiger housenumber data for the US

 
 

-Nominatim is able to use the official TIGER address set to complement the
-OSM house number data in the US. You can add TIGER data to your own Nominatim
-instance by following these steps:
+## Installing Tiger housenumber data for the US

 
 

-  1. Install the GDAL library and python bindings and the unzip tool
+Nominatim is able to use the official [TIGER](https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html)
+address set to complement the OSM house number data in the US. You can add
+TIGER data to your own Nominatim instance by following these steps. The
+entire US adds about 10GB to your database.

 
 

-       * Ubuntu: `sudo apt-get install python-gdal unzip`
-       * CentOS: `sudo yum install gdal-python unzip`
-
-  2. Get preprocessed TIGER 2015 data and unpack it into the
+  1. Get preprocessed TIGER 2019 data and unpack it into the

      data directory in your Nominatim sources:
 
         cd Nominatim/data
      data directory in your Nominatim sources:
 
         cd Nominatim/data

-        wget https://nominatim.org/data/tiger2017-nominatim-preprocessed.tar.gz
-        tar xf tiger2017-nominatim-preprocessed.tar.gz
+        wget https://nominatim.org/data/tiger2019-nominatim-preprocessed.tar.gz
+        tar xf tiger2019-nominatim-preprocessed.tar.gz
+
+    `data-source/us-tiger/README.md` explains how the data got preprocessed.

 
 

-  3. Import the data into your Nominatim database: 
+  2. Import the data into your Nominatim database:

 
         ./utils/setup.php --import-tiger-data
 
 
         ./utils/setup.php --import-tiger-data
 

-  4. Enable use of the Tiger data in your `settings/local.php` by adding:
+  3. Enable use of the Tiger data in your `settings/local.php` by adding:

 
          @define('CONST_Use_US_Tiger_Data', true);
 
 
          @define('CONST_Use_US_Tiger_Data', true);
 

-  5. Apply the new settings:
+  4. Apply the new settings:

 
 ```sh
     ./utils/setup.php --create-functions --enable-diff-updates --create-partition-functions
 ```
 
 
 ```sh
     ./utils/setup.php --create-functions --enable-diff-updates --create-partition-functions
 ```
 

-The entire US adds about 10GB to your database.
-
-You can also process the data from the original TIGER data to create the
-SQL files, Nominatim needs for the import:
-
-  1. Get the TIGER 2017 data. You will need the EDGES files
-     (3,234 zip files, 11GB total). Choose one of the two sources:
-
-         wget -r ftp://ftp2.census.gov/geo/tiger/TIGER2017/EDGES/
-         wget -r ftp://mirror1.shellbot.com/census/geo/tiger/TIGER2017/EDGES/

 
 

-     The first one is the original source, the second a considerably faster
-     mirror.
+## Updates

 
 

-  2. Convert the data into SQL statements: 
-
-         ./utils/imports.php --parse-tiger <tiger edge data directory>
-
-Be warned that this can take quite a long time. After this process is finished,
-the same preprocessed files as above are available in `data/tiger`.
-
-# Updates
-
-There are many different possibilities to update your Nominatim database.
+There are many different ways to update your Nominatim database.

 The following section describes how to keep it up-to-date with Pyosmium.
 For a list of other methods see the output of `./utils/update.php --help`.
 
 The following section describes how to keep it up-to-date with Pyosmium.
 For a list of other methods see the output of `./utils/update.php --help`.
 

-### Installing the newest version of Pyosmium
+!!! warning
+    If you have configured a flatnode file for the import, then you
+    need to keep this flatnode file around for updates as well.
+
+#### Installing the newest version of Pyosmium

 
 

-It is recommended to install Pyosmium via pip. Run (as the same user who
-will later run the updates):
+It is recommended to install Pyosmium via pip. Make sure to use python3.
+Run (as the same user who will later run the updates):

 
 ```sh
 
 ```sh

-pip install --user osmium
+pip3 install --user osmium

 ```
 
 ```
 

-Nominatim needs a tool called `pyosmium-get-updates` that comes with
+Nominatim needs a tool called `pyosmium-get-updates` which comes with

 Pyosmium. You need to tell Nominatim where to find it. Add the
 following line to your `settings/local.php`:
 
 Pyosmium. You need to tell Nominatim where to find it. Add the
 following line to your `settings/local.php`:
 


@@ -174,14 +281,14 @@ following line to your `settings/local.php`:
 The path above is fine if you used the `--user` parameter with pip.
 Replace `user` with your user name.
 
 The path above is fine if you used the `--user` parameter with pip.
 Replace `user` with your user name.
 

-### Setting up the update process
+#### Setting up the update process

 
 Next the update needs to be initialised. By default Nominatim is configured
 to update using the global minutely diffs.
 
 If you want a different update source you will need to add some settings
 to `settings/local.php`. For example, to use the daily country extracts
 
 Next the update needs to be initialised. By default Nominatim is configured
 to update using the global minutely diffs.
 
 If you want a different update source you will need to add some settings
 to `settings/local.php`. For example, to use the daily country extracts

-diffs for Ireland from geofabrik add the following:
+diffs for Ireland from Geofabrik add the following:

 
     // base URL of the replication service
     @define('CONST_Replication_Url', 'https://download.geofabrik.de/europe/ireland-and-northern-ireland-updates');
 
     // base URL of the replication service
     @define('CONST_Replication_Url', 'https://download.geofabrik.de/europe/ireland-and-northern-ireland-updates');


@@ -197,16 +304,18 @@ To set up the update process now run the following command:
 It outputs the date where updates will start. Recheck that this date is
 what you expect.
 
 It outputs the date where updates will start. Recheck that this date is
 what you expect.
 

-The --init-updates command needs to be rerun whenever the replication service
+The `--init-updates` command needs to be rerun whenever the replication service

 is changed.
 
 is changed.
 

-### Updating Nominatim
+#### Updating Nominatim

 
 The following command will keep your database constantly up to date:
 
     ./utils/update.php --import-osmosis-all
 
 
 The following command will keep your database constantly up to date:
 
     ./utils/update.php --import-osmosis-all
 

-(Note that even though the old name "import-osmosis-all" has been kept for compatibility reasons, Osmosis is not required to run this - it uses pyosmium behind the scenes.)
+(Note that even though the old name "import-osmosis-all" has been kept for
+compatibility reasons, Osmosis is not required to run this - it uses pyosmium
+behind the scenes.)

 
 If you have imported multiple country extracts and want to keep them
 up-to-date, have a look at the script in
 
 If you have imported multiple country extracts and want to keep them
 up-to-date, have a look at the script in