Re: enlistment of native connections for optimistic txs

[Craig L Russell]

Hi Guido,

On Apr 16, 2007, at 4:39 AM, Guido Anzuoni wrote:

Hi to all,

be very misleading.

I agree that using datastore transaction term on the subject topic could

There's always been a bit of confusion when talking about datastore transaction. In the proposed text, I've tried to use the term "native datastore transaction" when referring to the underlying transaction in the datastore.

What we are discussing here is the retain policy of the "connection" to

the native datastore the PM is applying.
According to Matthew proposal the result should be:

Connection getDataStoreConnection()

This method is equivalent to getDataStoreConnection
(pm.currentTransaction().isActive()). That is, it defaults to
getDataStoreConnection(true) if a JDO transaction is active, and
getDataStoreConnection(false) if not.

JDOConnection getDataStoreConnection(boolean enlist)

Regardless the type of transaction (optimistic or datastore),
if this method is called outside an active transaction, with the

underlying datastore engine.

enlist parameter false, the object returned will be a brand new connection obtained from the

Not exactly true if the jdo provider uses connection pooling.

If this method is called outside an active



following:
Case l enlist=false
the object returned will be a brand new connection obtained by the

the returned connection.

transaction, with the enlist parameter true, JDOUserException is thrown. If this method is called inside an active transaction the behavior is the underlying datastore engine. The PersistenceManager will never deliberately use

There's no difference between the connection returned here and any other connection that might be used for optimistic transactions. The main point is that the connections are auto-commit true and don't affect running transactions.

Case 2 enlist=true

for the rest of the transaction anyway, this connection is returned.

for the rest of the transaction, a new connection is obtained by the

management; this connection is then returned.

If the PersistenceManager has already acquired a connection that it would use If the PersistenceManager has not acquired yet a connection that it would use underlying datastore engine and permanently assigned for the current transaction

All this is true.



Thanks,

Craig

You present the information in a slightly different format. I'll review this when I write the text for the specification.

Guido.

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!

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