[OSM-dev] OSM Database Infrastructure

[Robert (Jamie) Munro]

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SteveC wrote:
| On 5 Jan 2008, at 20:51, Ian Dees wrote:
|
|> Hello,
|>
|> Last week I started editing OSM data and found it to be a very
|> interesting and fulfilling experience. Of all the community-driven
|> and open-source projects I've seen, OSM is by far the most
|> interesting and useful.
|>
|> The reason I'm e-mailing you is to ask about the server and database
|> infrastructure. After showing the project to a couple of my computer
|> science professors, they were surprised that there is one database
|> server that handles such a large load.

The database load isn't that high because the database is basically only
used for editing. Most viewing is of pre-rendered maps.

|> Has there been any research
|> into splitting the load up between several region-specific database
|> servers? I would think that since editors usually don't need to
|> cross continental boundaries, the data for continents could be split
|> up between several servers, distributing the load among the machines
|> and making the end user experience faster.

AFAICS, Spain, South Africa, China, India etc. are all the same
landmass, so can't easily be split. You could put the UK on it's own
server as it has quite a lot of data, but there is still the problem of
~ ferry routes etc. that connect the land masses. If you solve this
issue, you may as well divide the servers arbitrarily, say at the z12
tile level, using the lower bits of the z12 tile numbers to select a server.

If you attempt to divide by logical land masses, some will remain
underused in places that don't have much data, while others will be
overloaded. Even if you drew the borders of the areas carefully, they
would still fluctuate in usage with time zones.

Robert (Jamie) Munro
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