Re: Thread safe stored procedure

["Fred Kulack" <kulack@xxxxxxxxxx>]

On 07/13/2001 at 10:04:45 AM, owner-java400-l@midrange.com wrote:
The use of connection pools should enable a thread safe use of stored
procedure calls.
I was wondering if there was a way to ensure this safety at the stored
procedure level.
I remember having heard something like that for SQL stored procedure.
Does this exist for RPG LE stored procedures?
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Most of your thread safety concerns when calling stored procedures
via Java/JDBC are taken care of in a fashion unrelated to connection pools.
1) Each JDBC connection creates a seperate backend agent that
serves as the context for your connection, and it runs your stored
procedure.
The backend agent job is single threaded and since its a seperate
job from your multi-threaded application, you shouldn't have
thread safety concerns here.

2) The Java connection and statement objects are thread safe,
and access to the connection is serialized.

So, regardless of how may threads are calling a stored
procedure using N connections in the application job,
Calls will be serialized by the connection object so
two calls against the same connection will occur
serially.

One thing that seems to be a possible problem that isn't
really thread safety as such....
If your stored procedure retains state between one call
and the next, you could (by sharing a connections between
threads), allow the state for one thread to be used by
another. In many cases, this is ok, in some it is not.

Did you have other thread safety concerns?


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Fred A. Kulack  -  AS/400e  Java and Java DB2 access, Jdbc, JTA, etc...
IBM in Rochester, MN  (Phone: 507.253.5982   T/L 553-5982)
mailto:kulack@us.ibm.com   Personal: mailto:kulack@bresnanlink.net
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