[OSM-dev] all things to all people

80n 80n80n at gmail.com
Tue Apr 22 20:16:09 BST 2008

On Tue, Apr 22, 2008 at 3:39 PM, Frederik Ramm <frederik at remote.org> wrote:

> Hi,
> >> I think I'd trust Tom more than anyone else in OSM to understand the
> >> load which a given feature is going to place on the servers,
> >
> > Thats not the point, its not about x number of CPU seconds per request
> > - its that the statistics are fundamentally different for, say,
> > running a WMS and running a tile server. One scales, one doesn't.
> ALL problems regarding read-access scalability can be solved by
> implementing a proper "feed" mechanism (or DB slaves or whatever you
> want to call it). We have made steps in that direction with the
> weekly dumps, daily diffs, hourly diffs, and OsmXAPI is doing its
> best to keep a current data set with these services. Tiles at Home read
> requests have already moved off the main API to OsmXAPI, and OsmXAPI
> scales perfectly. The only thing that isn't perfect about OsmXAPI is
> that its data may still be two hours old which is good enough for
> many cases, but still not "the real thing" (not good enough to base
> an export tab on).

Since the minute-diff was introduced OSMXAPI has been running, on average,
about 6 minutes behind the main database.

IMHO this is good enough for all purposes, except editing, which obviously
needs to act on the live data.


> I think if we invest a bit more work in that direction, then we'll
> end up with a central database that will only serve live editor read/
> writes, and everything else can be run from the slaves. It's not
> exactly a low-hanging fruit but not that difficult either, and the
> reward is not having to worry about numbers of read requests.
> Bye
> Frederik
> --
> Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"
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