[Geocoding] Increasing requests per second

[Sarah Hoffmann]

Hi,

the server at nominatim.openstreetmap.org currently serves
400 request/s and is expected to max out at 500 req/s. So
in principle it is possible with a single server.

If you are using the latest release, then it still runs with
non-persistent connections to the database. At this line:

https://github.com/openstreetmap/Nominatim/blob/627a487fcfd325f8a340f10298a961d15d2760b6/lib/db.php#L6

change $bPersistent to true per default. That should improve
performance quite a bit.

With latest master you can also reduce the database size
for your use case. The smaller the size the more of the
database you can keep in RAM. For infos on that feature
see http://nominatim.org/release-docs/develop/admin/Import-and-Update/#choosing-the-data-to-import

That said, tuning the servers to get the throughput does
require quite a bit of administration knowledge. Also
consider simply buying a couple of machines and distributing
the load. Nominatim can be run with WAL replication or
by setting up independent servers.

kind regards

Sarah



On Mon, Mar 25, 2019 at 07:57:06PM +0300, Mark Davies wrote:
> Hi All
> 
> I'm currently in the process of trying to improve the amount of geocodes
> per sec
> 
> I have the whole world on nominatim but only currently using a handful of
> countries
> Its running on 48gb ram and SSD's and is topping out around 62 per second
> with max CPU
> I know it needs at least 96gb ram however my question is regarding scaling
> and if its even possible to get near what I want
> 
> My target is 500 per second.
> I'm first wondering if this is a possibility, even with 128+ram
> I know there are many factors like similar cached requests etc, but someone
> might know if there is a limit on what nominatim can handle so I can adjust
> my expectations.
> 
> Also if there is a better solution for reverse geocoding with road speed
> data (extra_tags)
> Thanks!

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