[Geotools-devel] Oracle and listing type names

[Andrea A. <and...@ge...>]

Hi,
as an aside to the discussion about how slow ContentDataStore is to check
type names,
we've found that the Oracle JDBC driver is giving that inefficient code a
good help
to slow everything down to a cringe.

JDBCDataStore.createTypeNames() uses the JDBC metadata to list the available
tables.
Now, I believe most jdbc drivers will only list the tables available to the
user connecting,
but the Oracle driver does not, it lists _everything_, regardless of
whether you can list
it or not.
In a large installation, and in cases where one does not specify the schema
in order
to allow the user to access multiple schemas, we get the list of every
single table
avalable in the database.
This is very slow, but also stupid (think of a app showing the list of
tables to the
users, when adding a new layer).

So, here is the idea, what if we move the jdbc metadata scan down in the
dialects,
as the default implementation, thus allowing specific db implementations to
optimize out the driver in case there are better ways to list only the
tables
we're interested into?

For the Oracle case it seems we could leverage USER_TAB_PRIVS function:
the http://docs.oracle.com/cd/B14117_01/server.101/b10755/statviews_2661.htm
http://oracle.su/docs/11g/timesten.112/e13070/ttsql388.htm

Cheers
Andrea

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