2013/3/3 Kevin Grittner <kgrittn@ymail.com>:
> Rewriting queries using
> expressions which match the MV's query to pull from the MV instead
> of the underlying tables is the exception. While that is a "sexy"
> feature, and I'm sure one can construct examples where it helps
> performance, it seems to me unlikely to be very generally useful.
> I suspect that it exists mostly so that people who want to write an
> RFP to pick a particular product can include that as a requirement.
> In other words, I think the main benefit of automatic rewrite
> using an MV is marketing, not technical or performance.
I think that automatically using materialized views even when the
query doesn’t mention them directly, is akin to automatically using
indexes without having to mention them in the query. That way, queries
can be written the natural way, and “creating materialized views” is
an optimization that can be applied by a DBA without having to update
the application queries to use them.
Nicolas
--
A. Because it breaks the logical sequence of discussion.
Q. Why is top posting bad?