[EMAIL PROTECTED] wrote:
various people (not database experts) are pushing to install Oracle
cluster so that they can move all of these to one table with a
customerID column.
They're blowing smoke if they think Oracle can do this. One of my applications
had this exact same problem -- table-per-customer versus
big-table-for-everyone. Oracle fell over dead, even with the best indexing
possible, tuned by the experts, and using partitions keyed to the customerID.
We ended up breaking it up into table-per-customer because Oracle fell over
dead when we had to do a big update on a customer's entire dataset. All other
operations were slowed by the additional index on the customer-ID, especially
complex joins. With a table-for-everyone, you're forced to create tricky
partitioning or clustering, clever indexes, and even with that, big updates are
problematic. And once you do this, then you become heavily tied to one RDBMS
and your applications are no longer portable, because clustering, indexing,
partitioning and other DB tuning tricks are very specific to each RDBMS.
When we moved to Postgres, we never revisited this issue, because both Oracle
and Postgres are able to handle thousands of tables well. As I wrote in a
previous message on a different topic, often the design of your application is
more important than the performance. In our case, the table-per-customer makes
the applications simpler, and security is MUCH easier.
Oracle is simply not better than Postgres in this regard. As far as I know,
there is only one specific situation (discussed frequently here) where Oracle
is faster: the count(), min() and max() functions, and I know significant
progress has been made since I started using Postgres. I have not found any
other query where Oracle is significantly better, and I've found several where
Postgres is the clear winner.
It's telling that Oracle's license contract prohibits you from publishing
comparisons and benchmarks. You have to wonder why.
Craig
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