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https://issues.apache.org/jira/browse/KARAF-1572?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Claudio Corsi updated KARAF-1572:
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Attachment: GenericJDBCLock.patch
Jamie and Christain,
Here is the work that I completed that uses a different mechanism to associate
a master instance given 2 or more karaf instances. The new jdbc lock feature
does not replace the original version but was designed to offer another option
to the users. The main difference between this version and the current one is
that it does not open a long running transaction and it only uses simple
select, update and insert sql commands to manipulate the lock tables. The
other change is that it does not use the FOR UPDATE syntax that is not
available for all dbms.
I have not included any tests for this new feature but have tested this
successfully using the following dbms.
- SQL Server
- MySQL
- Postgresql
- Derby
I have not tried to test it against other dbms but all of the above
successfully dealt with a soft and hard failure of karaf. The soft failure is
the master karaf instance releasing the lock while the hard failure is the
master karaf instance crashing. In both cases, a single karaf instance of the
remaining slaves acquired the lock and became the master.
Note that those tests did not involve starting a karaf instance but instead I
created a simple java application that followed the same sequences of calls
that the karaf Main class does. I basically extracted those calls in a new
class and used that one. This allowed me to stop and start multiple instances
of the instances.
Feel free to look at the code and let me know if this seems to a be viable
solution as an addition to the current JDBC lock mechanism.
Note that the two classes include javadoc explaining how this works and what is
expected from the user. Also note that the only difference between the current
required properties and this new version is that the new version requires the
master instance lock_delay and does not require a timeout value since we are
not using a long running transaction.
> Add SQL Server Support for JDBC Lock
> -------------------------------------
>
> Key: KARAF-1572
> URL: https://issues.apache.org/jira/browse/KARAF-1572
> Project: Karaf
> Issue Type: Improvement
> Components: karaf-instance
> Affects Versions: 2.2.7
> Reporter: Claudio Corsi
> Fix For: 2.2.9, 2.3.1, 3.1.0
>
> Attachments: GenericJDBCLock.patch
>
>
> The current JDBCLock implementations do not work when using Microsoft SQL
> Server since this requires that you use a CURSOR with the SELECT statement.
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