RE: JT400 / JTOpen Statement Pooling -- JAVA400-L

Joe,

1. Statements Pool (Caching)
When creating a prepared statement (with default settings) the JT400 jdbc
driver communicates with the AS/400. When I then execute the prepared
statement the jdbc driver will again communicate with the AS/400. If I were
to prepare the same statement on the same connection I see the jdbc driver
communicating for the prepared and for the execute (The statement has
already been prepared on the connection and there is no need to communicate
with the AS/400 when preparing the same statement on the same connection).
http://www-106.ibm.com/developerworks/java/library/j-jdbcnew/  (Prepared
statement pooling)

When I have extended dynamic enabled I do not see the jdbc driver
communicating with the AS/400 if I were to prepare a statement for a second
time (if it was already prepared on the connection). For this to be work
properly you must use parameter markers in the sql statement.

2. JT400 Settings
The specific JT400 properties that I was referring to are "extended
dynamic", "package", "package cache" and "package library".

The troubling aspect of the conversation was that they indicated that JT400
does not do statement pooling. In WebSphere when you define a connection
pool you can set the statement cache size, but the Java code is not running
on WebSphere. They suggested that we write our own statement pooling code
(They indicated that JT400 does do caching of access paths when you use
extended dynamic).

The web application is performing in excess of 240,000 queries per hour.
Reducing overhead of the jdbc driver is very important for us at this time.
If each prepare is communicating with the AS/400 you have at least 240,000
interactions with the AS/400 that could have been avoided.

Is there a difference between "extended dynamic" and prepared statement
pooling (lets use the prepared statement pooling description as explained in
the article on developer works)?

Etienne

-----Original Message-----
From: java400-l-bounces@xxxxxxxxxxxx
[mailto:java400-l-bounces@xxxxxxxxxxxx]On Behalf Of Joe Pluta
Sent: Tuesday, March 18, 2003 10:14 PM
To: Java Programming on and around the iSeries / AS400
Subject: RE: JT400 / JTOpen Statement Pooling


Etienne, why are you troubled?  IBM owns JT400 (and JTOpen), so I would have
thought you would have asked them these questions.

Let me try to address a few things, though:

1. What do you think prepared statement pooling is?  Remember, JDBC 3.0
doesn't say anything about the implementation of PSP, simply that there is
an interface for it.  Now, do you expect PSP to work across sessions, across
connections, or only within a single connection?

2. Which settings?

3. I don't know that they relate at all.

4. I recommend connection pooling for any application that has an unknown
but potentially very large number of connections.  This is typically the
case in an Internet application.  For a smaller number of users, I still
prefer persistent connections held at the session level.


> -----Original Message-----
> From: java400-l-bounces@xxxxxxxxxxxx
> [mailto:java400-l-bounces@xxxxxxxxxxxx]On Behalf Of Etienne Richards
> Sent: Tuesday, March 18, 2003 8:30 PM
> To: java400-l@xxxxxxxxxxxx
> Subject: JT400 / JTOpen Statement Pooling
>
>
> All (and Joe Pluta),
>
> Today I had a nice long conference call with IBM regarding JDBC and
> Connection Pooling, Prepared Statement Pooling and Extended Dynamic
> settings.
>
> I am troubled...
>
> 1. Does the latest JT400 jdbc driver do prepared statement pooling?
>       1.1. If it does, how do I enable it?
>       1.2. If it does not, when will it?
>
> 2. Is it worth using the extended dynamic settings that are available in
> JT400 if the client is not running on an AS/400?
>
> 3. How does caching of Access Paths (Extended Dynamic) and Prepared
> Statement pooling relate to each other. How are the caching of
> Access Paths
> and ODP's different (as viewed from a jdbc client)?
>
> 4. Would you recommend using the JT400 connection pool for
> applications that
> are not running in WebSphere?
>
> Any comments or answers would be appreciated.
>
> Thanks,
> Etienne

_______________________________________________
This is the Java Programming on and around the iSeries / AS400 (JAVA400-L)
mailing list
To post a message email: JAVA400-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/java400-l
or email: JAVA400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/java400-l.