On 15 Apr 2013, at 12:35, "Lebling, David (US SSA)"
<[email protected]> wrote:
> Andy,
>
> I was hoping you might have some guidance as to what you mean by "You need to
> control the JDBC transaction in your code to get isolation between JVMs."
>
> Is there some interface in SDB that will accomplish this, or does this
> require SQL-implementation-specific code, thus tearing down the SDB façade?
> If it does require such implementation-specific code, do you have any
> pointers to examples which do it correctly? Is it necessary to write one's
> own transaction begin/commit/abort methods?
SDB (as you'd expect) handles transactions itself by default. All model
operations happen in a single transaction, with a minor wrinkle around really
big loads (it will start committing every 20,000 triples iirc to avoid huge
transactions).
You can also wrap operations like this to get some of that behaviour across a
number of operations:
model.notifyEvent(GraphEvents.startRead) ;
try {
... do add/remove operations ...
} finally {
model.notifyEvent(GraphEvents.finishRead) ;
}
However it's not especially smart, so you can take control of the transaction
yourself by setting autocommit to false on the JDBC connection. SDB will then
assume the client is responsible for managing the transactions.
Just remember to commit() and reset autocommit when you finish.
Damian
