[ 
https://issues.apache.org/jira/browse/AMQ-6099?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Tim Bain updated AMQ-6099:
--------------------------
    Description: 
The current KahaDB implementation only allows a single OpenWire version to be 
read from the store.  This works fine during normal operations, but when a user 
upgrades to a version of ActiveMQ that uses a different OpenWire version, the 
new broker is unable to read any persisted messages from the store because of 
the version mismatch, as described in AMQ-5995.

Broker upgrades are going to happen, and the requirement that they be done with 
an empty message store, or that the user apply temporary workarounds like 
running the old broker in a networked configuration that's not the standard 
config for the cluster, leads to a less-than-satisfactory experience during the 
upgrade. As much as possible, broker upgrades should be seamless; sometimes 
that's not possible, but in this case it seems like code that would be able to 
read any version of OpenWire but only write the current one (and that could be 
less-efficient with older versions if necessary) wouldn't be all that hard and 
would eliminate this problem.

  was:
The current KahaDB implementation only allows a single OpenWire version to be 
read from the store.  This works fine during normal operations, but when a user 
upgrades to a version of ActiveMQ that uses a different OpenWire version, the 
new broker is unable to read any persisted messages from the store because of 
the version mismatch, as described in AMQ-5995.

Broker upgrades are going to happen, and the requirement that they be done with 
an empty message store, or that the user apply temporary workarounds like 
running the old broker in a networked configuration that's not the standard 
config for the cluster, leads to a less-than-satisfactory experience during the 
upgrade. As much as possible, broker upgrades should be seamless; sometimes 
that's not possible, but in this case it seems like code that would be able to 
read any version of OpenWire but only write the current one (and that could be 
less-efficient with older versions if necessary) wouldn't be all that hard and 
would eliminate this problem.

Alternatively, we could create a command-line utility to transform a set of 
KahaDB data files from an (offline) broker from one version to another. That's 
a little clunkier for the user, but reasonable if it's substantially easier to 
implement.


I split out the suggestion for a utility to migrate KahaDB data files to a 
different OpenWire version into a stand-alone issue (AMQ-6103), to allow each 
JIRA entry be focused on only one feature and evaluated on its own merits.

> Allow broker to read any OpenWire version from KahaDB
> -----------------------------------------------------
>
>                 Key: AMQ-6099
>                 URL: https://issues.apache.org/jira/browse/AMQ-6099
>             Project: ActiveMQ
>          Issue Type: New Feature
>          Components: KahaDB
>    Affects Versions: 5.x
>            Reporter: Tim Bain
>
> The current KahaDB implementation only allows a single OpenWire version to be 
> read from the store.  This works fine during normal operations, but when a 
> user upgrades to a version of ActiveMQ that uses a different OpenWire 
> version, the new broker is unable to read any persisted messages from the 
> store because of the version mismatch, as described in AMQ-5995.
> Broker upgrades are going to happen, and the requirement that they be done 
> with an empty message store, or that the user apply temporary workarounds 
> like running the old broker in a networked configuration that's not the 
> standard config for the cluster, leads to a less-than-satisfactory experience 
> during the upgrade. As much as possible, broker upgrades should be seamless; 
> sometimes that's not possible, but in this case it seems like code that would 
> be able to read any version of OpenWire but only write the current one (and 
> that could be less-efficient with older versions if necessary) wouldn't be 
> all that hard and would eliminate this problem.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to