[OSM-dev] Minute Diffs Broken

Tom Hughes tom at compton.nu
Tue May 5 08:39:59 BST 2009

Brett Henderson wrote:

> That does look interesting.  I'd hope to use that outside the main 
> database though.  My thoughts were to use triggers to populate short 
> term flag tables which a single threaded process would read, use as keys 
> to select modified data into an offline database, then clear.  This 
> offline database could then use a queueing system such as PgQ (I haven't 
> seen it before, will have to check it out) to send events to the various 
> consumers of the data.  I'd like to minimise access to the central 
> database if possible because 1. it will scale better, and 2. it adds 
> less burden to existing DBAs.

It is highly unlikely that anything which requires modifications to the 
database schema and/or adding triggers or anything like that to the 
database will be possible, at least in the short to medium term.

We're only just getting things stable again and I have no desire to 
start fiddling with things just yet - we need time to let what we have 
bed in properly.

On top of that if we're going to start talking about replication style 
solutions then we will need to look carefully at all the available 
systems and consider what will best lend itself to what will doubtless 
be our need to scale to multiple database servers in the future. That 
isn't something we can do quickly.


Tom Hughes (tom at compton.nu)

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