Hi Don,
I would recommend trying with Sequoia 2.10 (latest build 2.10.9).
The Sequoia 3.0 code base is pretty unstable. There are some modest
changes in VDB definition formats but otherwise the change is not hard.
For other people who may be listening on the list we (Continuent, the
humble supporters of Sequoia) do not intend to port any additional
features or fixes in to Sequoia 3.0. All production work for our
commercial products is going into Sequoia 2.10.
Cheers, Robert
Robert Hodges, CTO, Continuent, Inc.
Email: [EMAIL PROTECTED]
Mobile: +1-510-501-3728 Skype: hodgesrm
On Aug 29, 2007, at 4:32 PM, Don Isenor wrote:
Apologies if this is not the proper channel, if so please direct me
accordingly...
When I test Sequoia with concurrent requests, I (almost always) get
this exception:
java.sql.SQLException: A query with id 0 has already been scheduled
This is occurring in AbstractScheduler.scheduleReadRequest(),
because there is already an id=0 request in activeReadRequests.
My configuration is: a single JBoss (4.05) talking to a single
Sequoia (3.0 Beta 2) controller with two MySQL (5.0.41) backends.
Poking around in the Sequoia source code, and running it under the
debugger, I notice that "AbstractRequest.id" is not set for many
(if not all) queries. Under light or non-concurrent load this is
not a problem, but with concurrent requests, sooner or later the
scheduler is presented with one of these id=0 requests before it
has had time to remove the previous one. Result: the exception I am
seeing.
The problem goes away if I unconditionally set the id in
VirtualDatabaseWorkerThread.setRequestParameters(), i.e., instead
of this:
if (request.isAutoCommit() && transactionStarted)
{
vdb.commit(tid, writeQueryExecutedInThisTransaction,
!queryExecutedInThisTransaction);
return false;
}
else
request.setTransactionId(tid);
request.setId(vdb.getNextRequestId());
return transactionStarted;
do this:
request.setId(vdb.getNextRequestId());
if (request.isAutoCommit() && transactionStarted)
{
vdb.commit(tid, writeQueryExecutedInThisTransaction,
!queryExecutedInThisTransaction);
return false;
}
else
request.setTransactionId(tid);
return transactionStarted;
but this is just a kludge to illustrate my problem and hopefully
point the way to a solution.
Is this a known problem? Or maybe I have configured things
incorrectly?
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