[OSM-talk] Live Data - all new Data in OSM

Frederik Ramm frederik at remote.org
Wed May 13 01:27:58 BST 2009


> the least invasive way is to use the minutely diffs, as it doesn't
> touch the API or DB servers at all.

Sure, but they are (a) delayed by 5 minutes and (b) broken ;-)

I was initially opposed to the concept of diffs. I remember a developer 
meeting in Essen in 2007 where I rather violently requested more 
frequent updates and NickB said something like "we could do daily or 
hourly diffs" and I said "I want the f*ing real thing, not canned diffs".

I must say that, especially with the convenience Osmosis brings in 
dealing with them, I have meanwhile changed my mind. The diffs are a 
very crude solution but they work remarkably well, and they are quite 
robust compared to some kind of replication feed that may go out of sync 
at any time.

I still think that there are use cases for almost-realtime feeds but the 
diffs work for most people. - I didn't know the original poster was 
unaware of the diffs; I assumed he must know the diffs and was looking 
for something better!

> given that there are more efficient ways of doing the database
> replication than aggregating these feeds from all the different API
> servers into a coherent whole, 

As I said in another post, I was under the impression that while you can 
easily have any number of servers running API daemons on them, you'd 
rather not stuff too much into the database because at least for write 
requests we'll be stuck with it for a long while to come. But hey, maybe 
I underestimate the Postgres factor ;-)

> unless, of course, you're talking about twittering the updates. that
> would be teh moar ;-)

For once, it would not be TomH who bans an IP range then ;-)


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

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