NoQueryOptimize/10gR2

[bdirks]

I read in some past posts about setting Oracle.NoQueryOptimize to True when running against an Oracle 10gRelease 2 server and that this would "fix" these mysterious DB errors we've been getting in our Delphi apps.

This property sounds pretty important to just change from False to True. From the sound of the name I would think it would have an impact on query performance.

So, Marco, could you give us a an explanation of what this property does and what it can affect when True and when it's set to False?

I have a client that is seeing all kinds of DB errors when our app is under a heavy user load and 10GR2 is the only variable between this client and others running the same version of my app.

Thanks very much.

-Barry in Florida

 

[Marco Kalter]

When Oracle.NoQueryOptimize = True, queries that are repeatedly executed with the same SQL text will only be parsed once. After the first parse, the same parsed representation will be used, possibly with different bind variable values.

When Oracle.NoQueryOptimize = False, the SQL text will always be parsed. This can affect performance if you execute the same SQL text often, and when query execution & fetching does not take a lot of time.

In most applications (such as PL/SQL Developer), you will not notice a difference.