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USe of multiple DBs in a Single message Flow/Single unit of

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onceadam

Posted: Tue Jul 27, 2010 2:09 pm Post subject: USe of multiple DBs in a Single message Flow/Single unit of

Newbie

Joined: 03 Dec 2009
Posts: 2

Hi ,

We have a peculiar situation : I need to know what is the best Practice :
can we use multiple Dbs in a single message Flow/Single unit of work ; if yes can there be any possibility that a simple lookup on one DB can cause table Lock on the other DB which is being updated once the First one has been looked ?

If yes what can be done to replicate this scenario as i m convinced that the Lookup which i m doing on one DB cant lock the table on the 2nd DB but i am un able to prove my point.

Pl Guide

smdavies99

Posted: Tue Jul 27, 2010 11:18 pm Post subject:

Jedi Council

Joined: 10 Feb 2003
Posts: 6076
Location: Somewhere over the Rainbow this side of Never-never land.

firstly, yes you can use Multiple DB's in a message flow. I've used DB2 & SQL-Server.
There are well documented limitations on using only DB's of the same type within a compute (or similar) node.

For performance (especially in cases where there are multiple uses of a table or additional instances of a flow) you should make sure that your DB Reads are wherever possible, READ ONLY ones.
This may well involve having to use the PASSTHRU command. I know of some sites where this is verboten. But IMHO being able to ensure that your read on a table is read only and does not implicitly lock the rows or pages then I'd do it using the PASSTHRU command.
Beware the fact that the things you have to specify to avoid locking does differ between DB Types.

Now, onto your other problem.
I don't see how a lookup on one DB can cause a table lock on a different one. Their connection paths are different right from the start as the have different DSN's.
Perhaps you could be a bit more specific.
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Every time you reinvent the wheel the more square it gets (anon). If in doubt think and investigate before you ask silly questions.

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