Re: Net80 Connection re-use???

Yes, different vendors ODBC drivers will behave differently. What I meant by being blind to the RDBMS is that I would think the APPLICATION would probably not alter its behavior based on the RDBMS or the ODBC driver -- if it issues 3 connect requests for an operation, it would do so without regard to the RDBMS. In a sense, the ODBC driver makes the DBMS an abstract, generic entity FROM THE APPLICATION'S VIEWPOINT. Actually, we finally got a good lead late yesterday afternoon. I went back to the ODBC Administrator utility to see if there might be a DSN property I had overlooked. At the main panel was a tab -- "Connection Pooling." DOH! How had I overlooked that before? Turns out that it controls connection pooling properties at the driver level, while I had been focusing on the DSN level. Sure enough, pooling was turned on for the Oracle driver and turned off for the DB2 driver. We turned it on and re-ran our tests. This time the network trace showed connection requests that were consistent with what we saw in LISTENER.LOG when running against Oracle. We didn't see the performance improvement we were looking for, but at least now we have a firm enough grip on things to start narrowing our focus.

On Fri, 18 May 2001 01:42:11 +0200, "Mario" <mtechera_at_wpmc.com> wrote:

>Ed,
>
>just a short remark. Just because the app uses ODBC
>does not mean it is "RDBMS-blind".
>
>Even between different vendor ODBC driver implementation for the
>the same RDBMS there are huge differences (for Oracle I can
>name at least three drivers: Microsoft, Oracle and Neon).
>Each handles connectivity, multi-threading etc etc very differently.
>
>Talk to the software vendor and get as much info from them.
>Ask them why it is not certified with DB2 and if they
>have any "unsupported" recommendations you could try.
>
>Good luck,
>Mario
>
>
>"Ed Stevens" <Ed_Stevens_at_nospam.us.ibm.com> wrote in message
>news:3b03f24d.14198316_at_ausnews.austin.ibm.com...
>> Subject: Net80 Connection re-use???
>>
>> Even though much of this will be talking about DB2, it is setting up
>> my question about Oracle, so please bear with me.
>>
>> We are trying to install a packaged application and are having trouble
>> understanding some performance issues. The vendor says the application
>> is only certified to run against Oracle and Sybase, but I have a
>> management mandate to use DB2. The app connects via ODBC, so - in
>> theory - it should be blind to which RDBMS is used.
>>
>> The performance of the application was abyssimal beyond belief against
>> DB2, so we tried it against Oracle 8.1.6 to try to find any
>> differences and hopefully pin down exactly what was wrong.
>> Performance against Oracle was quite acceptable. The application and
>> both databases are loaded on the same NT server.
>>
>> Working with DB2, we determined that at least part of the problem was
>> that every connect request generated a series of requests to the
>> server's PDC (DB2 uses the OS to authenticate users). Once this was
>> determined I was able to do a network trace against a single command
>> line connection request. I then analyzed the trace to determine the
>> pattern of network traffic associated with a simple connection
>> request. Next we captured a network trace while exercising the
>> application and found that simply logging on to the application (which
>> does its own authentication based on a user table it maintains in the
>> database) generated 18 distinct connection requests.
>>
>> Next, we pointed the application to use the Oracle database, and
>> inspected the listener log file. I would have expected to see 18
>> (more or less) entries associated with logging on to the application,
>> but instead there were "only" 3.
>>
>> I know we're comparing apples and oranges (a network packet trace vs.
>> a listener log) but I would have expected to see some correlation for
>> a given operation. Could it be that Oracle is holding connections
>> open and so a repeated request in a short time frame would not require
>> the listener to get involved again?
>>
>> Does anyone have any observations on where I might go from here? We
>> have a mandate to use DB2 and that's not negotiable, so getting into
>> that discussion is pointless.
>>
>> --
>> Ed Stevens
>> (Opinions expressed do not necessarily represent those of my employer.)
>
>

--
Ed Stevens
(Opinions expressed do not necessarily represent those of my employer.)