[ https://forge.continuent.org/jira/browse/SEQUOIA-955?page=all ]
Emmanuel Cecchet resolved SEQUOIA-955:
--------------------------------------
Resolution: Fixed
Last fix successfully tested by Nick Smith
> Raidb1 load balancer and WaitForCompletionPolicy=first does not work
> --------------------------------------------------------------------
>
> Key: SEQUOIA-955
> URL: https://forge.continuent.org/jira/browse/SEQUOIA-955
> Project: Sequoia
> Type: Bug
> Components: Core
> Versions: Sequoia 2.10.9, Sequoia 2.10.8
> Environment: Windows XP, single controller, RAIDb-1,
> WaitForCompletionPolicy=first
> Reporter: xavier roques
> Assignee: Emmanuel Cecchet
> Priority: Critical
> Fix For: Sequoia 4.0, sequoia 2.10.10
>
>
> If have a VirtualDatabase with two backends db1 and db2, the load balancer is
> the Raiddb1 and the waitForCompletionPolicy is First.
> DB1 and DB2 are up. My application makes a lot of updates and after some time
> one of the Database is disabled.
> I don't undertstand why, because the database is up.
> After some searches I find out that database was disabled because of a
> timeout while trying to get a new connection.
> My pool of connection 50 was full ? But I released all my connections ...
> So now, I will explain why it does not work.
> There is a load balancer with two backends: Db1 and DB2. Each backend has its
> own queue and the queue of each backend is managed by different a thread.
> A lot of updates are sent to the virtualdatabase.
> The load balancer dispatches the requests on each backend. Now let's us
> suppose that the two following requests arrive.
> Request 1 (update)
> Request 2 (commit)
> The load balancer sends the request 1 on each backend and wait for the first
> completion.
> If the thread managing the DB1 executes the request 1 and send the result to
> the load balancer. It is possible that the load balancer dispatch the request
> 2 even if the Request 1 has not been started on the DB2.
> The code of the loadBalancer RAIDDB1.commit is:
> {code}
> for (int i = 0; i < nbOfThreads; i++)
> {
> DatabaseBackend backend = (DatabaseBackend) enabledBackends.get(i);
> if (backend.isStartedTransaction(lTid))
> commitList.add(backend);
> }
> {code}
> Unfortunately when this code is executed the backend DB2 may not have started
> to execute the request 1 so the commit will only be pushed on the backend 1.
> So when the request 1 will be executed on DB2, a new connection will be open
> and it will never be released because the commit will never be executed on
> the backend DB2.
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