Major Description
While searching for a workaround for issue AMQ-5284, I came across this issue.
To work around the serialization issue (AMQ-5284), I deleted the index snapshots from the LevelDB datastore. This will replay the logs to regenerate the index. However, if a log rotation has already occurred, you will get an infinite loop upon restart.
Here are the steps to reproduce what I am seeing:
Configure ActiveMQ 5.10.0 to use a LevelDB data store with the log size of about 1MB.
<persistenceAdapter>
<levelDB directory="${activemq.data}/leveldb" logSize="1000000" />
</persistenceAdapter>
Then I started up the broker and published 10,000 persistent messages to a queue, causing the log files to rotate (twice in my case). I see the following files in the data store folder:
-rw-rw-r--. 1 user users 1000071 Jul 30 11:15 0000000000000000.log -rw-rw-r--. 1 user users 1000009 Jul 30 11:16 00000000000f4287.log drwxrwxr-x. 2 user users 4096 Jul 30 11:16 00000000001e84d0.index -rw-rw-r--. 1 user users 1000000 Jul 30 11:17 00000000001e84d0.log drwxrwxr-x. 2 user users 4096 Jul 30 11:11 dirty.index -rw-rw-r--. 1 user users 0 Jul 30 11:11 lock drwxrwxr-x. 2 user users 4096 Jul 30 11:11 plist.index -rw-rw-r--. 1 user users 24 Jul 30 11:11 store-version.txt
I then consume 5,000 messages, which causes the first log to be deleted since it is no longer being referenced. I see the following log statements:
2014-07-30 11:29:14,960 | DEBUG | Log no longer referenced: 0 | org.apache.activemq.leveldb.LevelDBClient | Thread-2 2014-07-30 11:29:14,967 | DEBUG | Deleting log at 0 | org.apache.activemq.leveldb.LevelDBClient | Thread-2
And I see the remaining files in the data store folder (notice the 0000000000000000.log is gone):
-rw-rw-r--. 1 user users 1000009 Jul 30 11:16 00000000000f4287.log -rw-rw-r--. 1 user users 1000011 Jul 30 11:29 00000000001e84d0.log drwxrwxr-x. 2 user users 4096 Jul 30 11:29 00000000002dc71b.index -rw-rw-r--. 1 user users 1000000 Jul 30 11:29 00000000002dc71b.log drwxrwxr-x. 2 user users 4096 Jul 30 11:11 dirty.index -rw-rw-r--. 1 user users 0 Jul 30 11:11 lock drwxrwxr-x. 2 user users 4096 Jul 30 11:11 plist.index -rw-rw-r--. 1 user users 24 Jul 30 11:11 store-version.txt
At this point, I shut down the broker and here is the listing of what's left in the data store:
-rw-rw-r--. 1 user users 1000009 Jul 30 11:16 00000000000f4287.log -rw-rw-r--. 1 user users 1000011 Jul 30 11:29 00000000001e84d0.log -rw-rw-r--. 1 user users 1000000 Jul 30 11:29 00000000002dc71b.log drwxrwxr-x. 2 user users 4096 Jul 30 11:36 0000000000301737.index drwxrwxr-x. 2 user users 4096 Jul 30 11:11 dirty.index drwxrwxr-x. 2 user users 4096 Jul 30 11:11 plist.index -rw-rw-r--. 1 user users 24 Jul 30 11:11 store-version.txt
I then delete the index folder within the data store (in my case "0000000000301737.index"). I am doing this to force a replay of the logs to regenerate the index (due to the serialization issue I ran into).
And finally, this is the message I am getting once I start the broker back up (infinite loop of this same message, and I have to shut down the broker):
2014-07-30 11:40:27,415 | WARN | No reader available for position: 0, log_infos: {1000071=LogInfo(/home/user/apache-activemq-5.10.0/data/leveldb/00000000000f4287.log,1000071,1000009), 2000080=LogInfo(/home/user/apache-activemq-5.10.0/data/leveldb/00000000001e84d0.log,2000080,1000011), 3000091=LogInfo(/home/user/apache-activemq-5.10.0/data/leveldb/00000000002dc71b.log,3000091,0)} | org.apache.activemq.leveldb.RecordLog | main