Hi,
On 20 Dec 2008, at 15:01, Andrea Schiavini wrote:
Hallo!
I've been recently thinking about the possible different design
choices
offered by CouchDB, and - more generally - by Document Oriented
Databases.
Specifically, I considered the case of web applications like
Amazon.com,
where they need to have full consistency in some specific "fields",
like
item availability;
They actually don't. Enforcing consistency at their size is a lot more
expensive
than saying: "Sorry, we know we told you you can buy this, but we were
wrong,
here's a $20 cupon for your next purchase."
still, in the biggest part of their database (the one
about item descriptions, user details etc.), they can get huge
benefits from
a document oriented database.
How do they solve the problem of consistency? I think a good
solution could
be to use a two-database design, with a standard SQL database to
store only
item availability and critical data, and another document oriented
database
for everything else. Of course, a cross database relation has to be
built.
I've read that SimpleDB by amazon also offers eventual consistency,
like
CouchDB; and they also state that they're using SimpleDB for the
amazon.comwebsite. So, how do they solve this problem?
Amazon's CEO Werner Vogels describes their system in detail:
http://www.allthingsdistributed.com/2007/10/amazons_dynamo.html
Cheers
Jan
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