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Hi Emmanuel,

>> 1) Is it possible to configure the ports for file-transfers (tansfer
>> dump, restrore log, ...)
>>   
> Yes, you can configure the transfer dump port number. Check
> https://forge.continuent.org/jira/browse/SEQUOIA-830
> Restore log just uses the group communication so you should not have to
> set anything specific.
Thanks, thats what I've looking for. :)

>> 2) We are using Squirell_SQL for manual database queries and checks.
>> When we connect to the sequoia controller with it, no tabes are listed
>> for the database anymore. But we can execute any sql statement
>> sucessfully. Is there a problem with the metadata/schema browsing in
>> sequoia, or does it need configuring?
>>   
> I don't know exactly which JDBC call Squirrel is trying to do to fetch
> the schema. We just forward the call 'as is' to the underlying database.
> Sometimes the underlying driver expects null to fetch the entire schema
> and sometimes it expect '%' for all tables. What happens if you connect
> Squirrel directly to your database backend? Do you notice the same
> problem or is it Sequoia specific?
> 
It is Sequoia specific, but I'm not exactly sure which statement
Squirrel is issuing to the driver, but I get an exception that
getSuperTable(...) is an unsupported operation in the postgres driver.
This statement must fail also when connecting directly to the database.

I think there are two possibilities:

1) Sequoia does not forward the exception/response back 'as is' to the
client

2) Squirrel does look at the jdbc-url/driver metadata and do a special
handling for some databases which it does not for Sequoia.

Since I've also had this for MySQL (not only Postgres) I would opt for
option 2 and guess Squirrel does some db-specific lookup.

Thanks
Markus

> Thanks for your feedback,
> Emmanuel
>> Thanks again for all your help
>> Markus Wolf
>>
>> Linas Virbalas schrieb:
>>  
>>> Hello Markus, Emmanuel,
>>>
>>> I’m sorry if I’m creating a new thread with this message - I have just
>>> subscribed to this list and am replying with a new message.
>>>
>>> Markus, I would recommend you trying the attached JGroups over TCP
>>> protocol stack configuration. As it is built on a reliable TCP protocol
>>> which does fragmentation by itself your problem should be solved. You
>>> will need to replace the current JGroups configuration file (total.xml?)
>>> and restart the controllers for this change to work.
>>>
>>> Best luck!
>>> Linas
>>>
>>> On 9/18/08 7:44 PM, "Robert Hodges" <[EMAIL PROTECTED]>
>>> wrote:
>>>
>>>     ------ Forwarded Message
>>>     *From: *Markus Wolf <[EMAIL PROTECTED]>
>>>     *Reply-To: *Sequoia general mailing list
>>>     <[EMAIL PROTECTED]>
>>>     *Date: *Thu, 18 Sep 2008 09:34:25 -0700
>>>     *To: *Sequoia general mailing list
>>>     <[EMAIL PROTECTED]>
>>>     *Conversation: *[Sequoia] Sequoia Transaction Problem
>>>     *Subject: *Re: [Sequoia] Sequoia Transaction Problem
>>>
>>> Hi Emmanuel,
>>>
>>>    
>>>> You may have a problem in your group communication setup if the
>>>> fragmentation layer is not working in JGroups.
>>>>       
>>> Where could the problem in the fragmentation layer? We just use the
>>> default sequencer jgroups file shipped with sequoia.
>>> Can you point me to a good documentation source, since we are not firm
>>> with jgroups.
>>>
>>>    
>>>> You may also have to check your recovery log configuration to make
>>>> sure that the columns storing the SQL are large enough to contain the
>>>>  whole statement. Otherwise there is no limit on the statement size
>>>> in Sequoia, we do insert Blobs of several MB so few KB should not be
>>>> a problem.
>>>>       
>>> This should be no problem, since if we use only one controller all does
>>> work well. Even larger blobs.
>>>
>>> Thanks for your help
>>> Markus Wolf
>>>
>>>
>>>    
>>>> Keep us posted with your progress, Emmanuel
>>>>      
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>>>>>
>>>>> Hi Robert,
>>>>>
>>>>>
>>>>>        
>>>>>> What group communications are you using?  How were you able to
>>>>>> deduce that the problems were coming from group communications?
>>>>>>
>>>>>>
>>>>>>           
>>>>> we are using JGroups (default with 2.10.10). We asume it is the
>>>>> group communication, because when we have hanging transactions we
>>>>> lookup the transaction ids and then do a "dump transaction <id>" on
>>>>>  both controllers. On one of them (which got the initial statement)
>>>>>  the whole transaction statements are available, but on the second
>>>>> all parts - from the statement including the blob to the end of the
>>>>>  transaction - are missing. Therefore we asume that it was the
>>>>> group communication. Also with only one controller all does work
>>>>> well.
>>>>>
>>>>> Thanks Markus Wolf
>>>>>
>>>>>
>>>>>        
>>>>>> Thanks, Robert
>>>>>>
>>>>>> On 9/18/08 7:07 AM, "Markus Wolf" <[EMAIL PROTECTED]> wrote:
>>>>>>
>>>>>> Hi Emmanuel,
>>>>>>
>>>>>> we have had do reinitalize the whole cluster. To our luck this
>>>>>> was only a test environment and no production system. After
>>>>>> further investigating the problem we tracked it down to an error
>>>>>>  in the controller group communication. We are uploading files in
>>>>>>  our webapp which are afterwards stored as blobs in the database.
>>>>>>  The whole process does work when only one controller is running,
>>>>>>  but if the second controller is active only part of the
>>>>>> transaction is replicated to the second one and the transaction
>>>>>> on both controller hangs. The problem also only occurs if the
>>>>>> file is larger than 2,7k (at least in our tests). We also tested
>>>>>> with a 27k file which result in hanging transactions. No
>>>>>> exception is thrown from the controller or no log entry is done.
>>>>>>
>>>>>> Is there an option to specify the file limits? Or maybe could it
>>>>>> be related to our hsqldb recovery log and blob handling?
>>>>>>
>>>>>> Thanks for any help Markus Wolf
>>>>>>
>>>>>>
>>>>>>          
>>>>>>>>>> we are using Sequoia 2.10.10 and have two controllers on
>>>>>>>>>> dedicated systems each with one backend database.
>>>>>>>>>> Yesterday I started a backup on controller2 and after
>>>>>>>>>> that the database was not enabled again. So I restarted
>>>>>>>>>> the virtual-database but since that the controller hangs.
>>>>>>>>>>  After searching for some info about the problem (no log
>>>>>>>>>> file entries) I dicovered that there are 7 pending
>>>>>>>>>> transactions on controller1 which seem to block the
>>>>>>>>>> controller. They do not seem to timeout and I have found
>>>>>>>>>> no option to rollback/timeout them with the console or
>>>>>>>>>> JMX.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>                   
>>>>>>>>> Yes, it is true that there is no option in the console to
>>>>>>>>> rollback a transaction, this is probably a feature we
>>>>>>>>> should add. If you close the client connections (can
>>>>>>>>> probably easily be done by resetting the app. side
>>>>>>>>> connection pool) that will automatically rollback the
>>>>>>>>> connections. Open transactions usually come from an
>>>>>>>>> application that does not commit/rollback transactions in
>>>>>>>>> all cases (and thus transactions remain uncommitted).
>>>>>>>>> Another caveat of the JDBC API is that a commit/rollback
>>>>>>>>> automatically starts a new transaction. So if you don't
>>>>>>>>> force the connection to setAutoCommit(true) after a
>>>>>>>>> commit/rollback they will be in a new transaction. And
>>>>>>>>> Sequoia can only perform enable.disable/backup/shutdown
>>>>>>>>> operations on transaction boundaries. We never implemented
>>>>>>>>> a kill/abort command because it cannot be implemented
>>>>>>>>> deterministically (what do you do is the transaction has
>>>>>>>>> already committed on a backend and you try to cancel
>>>>>>>>> cluster-wide?). This could however be implemented for open
>>>>>>>>> transaction with no active request. Feel free to add a
>>>>>>>>> feature request in JIRA if you think this could be a useful
>>>>>>>>>  tool to have.
>>>>>>>>>
>>>>>>>>>                
>>>>>>>>>> Am I missing something? Can someone give me a hint on how
>>>>>>>>>>  to stabilize the system again. Or is the only solution
>>>>>>>>>> to kill both controllers, initialize the database again
>>>>>>>>>> (or restore from dump) and synchronize the controllers
>>>>>>>>>> again afterwards?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>                   
>>>>>>>>> In your case, the 2nd backend was still in backup mode
>>>>>>>>> waiting for transactions to complete. If you are not able
>>>>>>>>> to terminate the transactions by closing your application
>>>>>>>>> connections, you can reset the virtual database by using a
>>>>>>>>> force shutdown (this will abort pending transactions). You
>>>>>>>>> will probably have to resynchronize the 2nd controller with
>>>>>>>>>  its backend upon restart to make sure that they are
>>>>>>>>> properly synchronized.
>>>>>>>>>
>>>>>>>>> Hope this helps, Emmanuel
>>>>>>>>>
>>>>>>>>>                 
> 


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