Warning about client-server joins

Hello everybody,

   since I just spent two days investigating frequent freezes in a client/server (MS Access front-end, Oracle server) environment, I feel I should share the result, maybe someone can profit from it.

   Anyway, the freezes were actually severe performance problems, caused by full table scans on very large tables. The table had the right indexes, and looking at the queries in Access it was not immediately apparent why they were not used. As it turns out (and in hindsight, it's pretty logical), if an Oracle table is accidentally joined to a native Access table (i.e. not an attached table), then the Access engine indiscriminately chops the whole WHERE clause before submitting the SELECT statement to the server.

   Anyway, sorry for wasting the bandwidth, just happy about figuring out the problem...

• Janos