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From "Jesse Fugitt (JIRA)" <>
Subject [jira] [Commented] (AMQ-5394) Incorrect handling of duplicate update message commands in KahaDB can lead to broker startup errors
Date Thu, 16 Oct 2014 17:24:34 GMT


Jesse Fugitt commented on AMQ-5394:

After further testing, it looks like the metadata.lastUpdate location in KahaDB is being set
incorrectly in more places than just the function that handles update message (the add message
and remove message functions also appear to have branches where this can happen).  A more
complete patch will be needed to catch all the cases where this could occur.

> Incorrect handling of duplicate update message commands in KahaDB can lead to broker
startup errors
> ---------------------------------------------------------------------------------------------------
>                 Key: AMQ-5394
>                 URL:
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: Message Store
>    Affects Versions: 5.10.0
>            Reporter: Jesse Fugitt
>         Attachments: AMQ5394.patch
> When using the new (in 5.10) persistJMSRedelivered option to make sure all duplicates
are marked as redelivered (the activemq.xml config file used <policyEntry queue=">"
persistJMSRedelivered="true"></policyEntry>), we occasionally had a broker fail to
start up with the following error:
> 2014-10-07 17:31:15,117 | ERROR | Looking for key 7 but not found in fileMap: {8=db-8.log
number = 8 , length = 9132256} | | main
> 2014-10-07 17:31:15,117 | ERROR | Failed to start Apache ActiveMQ ([broker0, null],
Could not locate data file /local/temp/apache-activemq-5.10.0/data/kahadb/db-7.log) |
| main
> The root cause seems to be when KahaDB processes a "duplicate" update message command
or if it processes an update message command after the message has been removed from kahadb.
 The code in KahaDB logs a warning when this occurs from the following else statement and
then updates the metadata location and then exits the function as shown below:
> ...
> } else {
>             LOG.warn("Non existent message update attempt rejected. Destination: {}://{},
Message id: {}", command.getDestination().getType(), command.getDestination().getName(), command.getMessageId());
>         }
> metadata.lastUpdate = location;
> ...
> It turns out that the metadata.lastUpdate = location; line should not run if we took
the else branch above so the simple fix is to move that line up into the if block so that
it will not run after the log warning.  Once we did that, we no longer see the broker startup
errors.  Note that this log warning does not always lead to a broker startup error as it is
also related to writing at the end of a transaction log file or the checkpoint timer interval
so it is not simple to reproduce but we have not see the startup error once the metadata.lastUpdate
line was moved to the correct location.
> A patch will be provided to show the change.

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