Re: OpenBase & WebObjects for scaling
Re: OpenBase & WebObjects for scaling
- Subject: Re: OpenBase & WebObjects for scaling
- From: Chuck Hill <email@hidden>
- Date: Wed, 14 Jan 2009 11:24:51 -0800
On Jan 14, 2009, at 11:08 AM, Andrew Lindesay wrote:
Hello Chuck;
Another thing that's impressed me with OpenBase is the clustering
failover. I doubt many people have used this feature.
Any SQL written to any database in the cluster is automatically
propagated to other OpenBase databases in that cluster within five
seconds without any primary key collisions.
Do you know how OpenBase handles that? This is usually quite the
problem with clustering and replication. Does it need to have a
GUID as the primary key, or does it work with integers?
As far as I can remember (Scott, you can correct me if I am wrong)
it uses a ticker-tape style transaction log -- effectively "log
shipping". In this manner, transactions are written to a log and
then re-played on the other members of the cluster. To avoid
primary key conflicts, one employs the OB primary key generation
plugin. By using this, one member of the cluster issues primary
keys 10,20,30 and the next 11,21,31,41 etc...
That is an interesting way of handling it. It would limit you to 10
copies, but that would be more than enough.
Off the top of my head, I can't remember how conflicts between logs
get resolved -- again, perhaps somebody from Openbase can remind us.
Thanks
Chuck
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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