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 a38d8eea22cbf2dce1fa653cda6890a5e6e07b56..c80b54a047b28a0883a52f84f4796d0582008c3b 100644 (file)
--- a/docs/admin/Import-and-Update.md
+++ b/docs/admin/Import-and-Update.md
@@ -29,7 +29,7 @@ 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
 


@@ -41,14 +41,15 @@ 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
 This data is available as a binary download:
 
     cd $NOMINATIM_SOURCE_DIR/data

-    wget https://www.nominatim.org/data/wikimedia_importance.sql.gz
+    wget https://www.nominatim.org/data/wikimedia-importance.sql.gz

 
 

-The file is about 1GB and it adds around 10GB 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:* if you forgot to download the wikipedia rankings, you can also add
-them after the import by running `./utils/setup.php --import-wikipedia-articles`
-and then `./utils/update.php --recompute-importance`.
+!!! 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`.

 
 ### Great Britain, USA postcodes
 
 
 ### Great Britain, USA postcodes
 


@@ -63,7 +64,7 @@ involve a GB or US postcode. This data can be optionally downloaded:
 
 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
 
 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 32GB of RAM and around 800GB of SSD hard disks. Depending on your
+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.
 
 use case there are various ways to reduce the amount of data imported. This
 section discusses these methods. They can also be combined.
 


@@ -119,13 +120,16 @@ import styles available which only read selected data:
   Import all data necessary to compute addresses down to house number level.
 * **settings/import-full.style**
   Default style that also includes points of interest.
   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
 
 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 32GB RAM, 4 CPUS and SSDs. Note that
+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.
 
 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.
 


@@ -135,31 +139,68 @@ admin     |    5h        |  190 GB    |   20 GB
 street    |   42h        |  400 GB    |  180 GB
 address   |   59h        |  500 GB    |  260 GB
 full      |   80h        |  575 GB    |  300 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 an description of the
+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
 
 style format see [the development section](../develop/Import.md).
 
 ## Initial import of the data
 

-**Important:** first try the import with a small extract, for example from
-[Geofabrik](https://download.geofabrik.de).
+!!! 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
 
 Download the data to import and load the data with the following command
 from the build directory:
 
 ```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.

 
 

-Computing word frequency for search terms can improve the performance of
-forward geocoding in particular under high load as it helps PostgreSQL's query
-planner to make the right decisions. To recompute word counts run:
+### Notes on memory usage
+
+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


@@ -177,12 +218,13 @@ 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
 
 
 
 ## Installing Tiger housenumber data for the US
 

-Nominatim is able to use the official [TIGER](https://www.census.gov/geo/maps-data/data/tiger.html)
+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.
 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.


@@ -217,6 +259,10 @@ 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`.
 

+!!! 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. Make sure to use python3.
 #### Installing the newest version of Pyosmium
 
 It is recommended to install Pyosmium via pip. Make sure to use python3.


@@ -267,7 +313,9 @@ The following command will keep your database constantly up to date:
 
     ./utils/update.php --import-osmosis-all
 
 
     ./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