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Posted to commits@activemq.apache.org by bu...@apache.org on 2016/09/27 16:43:13 UTC
svn commit: r998396 - in /websites/production/activemq/content:
cache/main.pageCache kahadb.html
Author: buildbot
Date: Tue Sep 27 16:43:13 2016
New Revision: 998396
Log:
Production update by buildbot for activemq
Modified:
websites/production/activemq/content/cache/main.pageCache
websites/production/activemq/content/kahadb.html
Modified: websites/production/activemq/content/cache/main.pageCache
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Binary files - no diff available.
Modified: websites/production/activemq/content/kahadb.html
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--- websites/production/activemq/content/kahadb.html (original)
+++ websites/production/activemq/content/kahadb.html Tue Sep 27 16:43:13 2016
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<link href='http://activemq.apache.org/styles/highlighter/styles/shCore.css' rel='stylesheet' type='text/css' />
<link href='http://activemq.apache.org/styles/highlighter/styles/shThemeEclipse.css' rel='stylesheet' type='text/css' />
<script src='http://activemq.apache.org/styles/highlighter/scripts/shCore.js' type='text/javascript'></script>
- <script src='http://activemq.apache.org/styles/highlighter/scripts/shBrushJava.js' type='text/javascript'></script>
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</broker>
</pre>
-</div></div><h3 id="KahaDB-KahaDBProperties">KahaDB Properties</h3><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>property name</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>default value</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Comments</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>archiveCorruptedIndex</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, corrupted indexes found at startup will be archived (not deleted).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>archiveDataLogs</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, will move a message data log to the archive directory instead of deleting it.</p></t
d></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>checkForCorruptJournalFiles</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, will check for corrupted Journal files on startup and try and recover them.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>checkpointInterval</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>5000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Time (ms) before check-pointing the journal.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>checksumJournalFiles</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Create a checksum for a journal file - to enable checking for corrupted journals.</p><p>Before <strong>ActiveMQ 5.9.0</strong>: the default i
s <strong><code>false</code></strong>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>cleanupInterval</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>30000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Time (ms) before checking for a discarding/moving message data logs that are no longer used.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>compactAcksAfterNoGC</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>10</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.14.0</strong>: when the acknowledgement compaction feature is enabled this value controls how many store GC cycles must be completed with no other files being cleaned up before the compaction logic is triggered to possibly compact older acknowledgements spread across journal files into a new log file.  The lower the value set the faster the compaction may oc
cur which can impact performance if it runs to often.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>compactAcksIgnoresStoreGrowth</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.14.0</strong>: when the acknowledgement compaction feature is enabled this value controls whether compaction is run when the store is still growing or if it should only occur when the store has stopped growing (either due to idle or store limits reached).  If enabled the compaction runs regardless of the store still having room or being active which can decrease overall performance but reclaim space faster. </p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>concurrentStoreAndDispatchQueues</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confl
uenceTd"><p>Enable the dispatching of Queue messages to interested clients to happen concurrently with message storage.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>concurrentStoreAndDispatchTopics</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Enable the dispatching of Topic messages to interested clients to happen concurrently with message storage</p><div class="confluence-information-macro confluence-information-macro-warning"><span class="aui-icon aui-icon-small aui-iconfont-error confluence-information-macro-icon"></span><div class="confluence-information-macro-body">Enabling this property is not recommended.</div></div></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>directory</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>activemq-data</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p
>The path to the directory to use to store the message store data and log files.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>directoryArchive</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Define the directory to move data logs to when they all the messages they contain have been consumed.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>enableAckCompaction</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.14.0</strong>: this setting controls whether the store will perform periodic compaction of older journal log files that contain only Message acknowledgements.  By compacting these older acknowledgements into new journal log files the older files can be removed freeing space and allowing the message store to
continue to operate without hitting store size limits.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>enableIndexWriteAsync</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If set, will asynchronously write indexes.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>enableJournalDiskSyncs</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Ensure every journal write is followed by a disk sync (JMS durability requirement).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>ignoreMissingJournalfiles</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, will ignore a missing message log file.</p></td></tr><tr><td colspan=
"1" rowspan="1" class="confluenceTd"><p><code>indexCacheSize</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>10000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Number of index pages cached in memory.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>indexDirectory</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"> </td><td colspan="1" rowspan="1" class="confluenceTd"><p><span>From <strong>ActiveMQ 5.10.0</strong>: If set, configures where the KahaDB index files (<strong><code>db.data</code></strong> and <strong><code>db.redo</code></strong>) will be stored. If not set, the index files are stored in the directory specified by the <strong><code>directory</code></strong> attribute.</span></p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>indexWriteBatchSize</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="
1" rowspan="1" class="confluenceTd"><p>Number of indexes written in a batch.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>journalMaxFileLength</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>32mb</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A hint to set the maximum size of the message data logs.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>maxAsyncJobs</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>10000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>The maximum number of asynchronous messages that will be queued awaiting storage (should be the same as the number of concurrent MessageProducers).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>preallocationScope</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><code>entire_journal</code></td><td colspan="1" rowspan="1" class="confluenceTd"><
p>From <strong>ActiveMQ 5.14.0</strong>: this setting configures how journal data files are preallocated. The default strategy preallocates the journal file on first use using the appender thread. </p><ul><li><strong><code>entire_journal_async</code></strong> will use preallocate ahead of time in a separate thread.</li><li><strong><code>none</code></strong> disables preallocation.</li></ul><p>On SSD, using <strong><code>entire_journal_async</code></strong> avoids delaying writes pending preallocation on first use.</p><p><strong>Note</strong>: on HDD the additional thread contention for disk has a negative impact. Therefore use the default.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>preallocationStrategy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>sparse_file</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.12.0</strong>: This setting configures how the broker will tr
y to preallocate the journal files when a new journal file is needed.</p><ul><li><strong><code>sparse_file</code></strong> - sets the file length, but does not populate it with any data.</li><li><strong><code>os_kernel_copy</code></strong> - delegates the preallocation to the Operating System.</li><li><strong><code>zeros</code></strong>  - configures ActiveMQ to do the preallocation by writing <strong><code>0x00</code></strong> to all of the positions in the journal file.</li></ul></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>storeOpenWireVersion</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>11</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Determines the version of OpenWire commands that are marshaled to the KahaDB journal. </p><p>Before <strong>ActiveMQ 5.12.0</strong>: the default value is <strong><code>6</code></strong>.</p><p>Some features of the broker depend on information stored in the Op
enWire commands from newer protocol revisions and these may not work correctly if the store version is set to a lower value.  KahaDB stores from broker versions greater than 5.9.0 will in many cases still be readable by the broker but will cause the broker to continue using the older store version meaning newer features may not work as intended. </p><p>For KahaDB stores that were created in versions prior to <strong>ActiveMQ 5.9.0</strong> it will be necessary to manually set <strong><code>storeOpenWireVersion="6"</code></strong> in order to start a broker without error.</p></td></tr></tbody></table></div><p>For tuning locking properties please take a look at <a shape="rect" href="pluggable-storage-lockers.html">Pluggable storage lockers</a></p><h3 id="KahaDB-Slowfilesystemaccessdiagnosticlogging">Slow file system access diagnostic logging</h3><p>You can configure a non zero threshold in milliseconds for database updates. If database operation is slower than that threshold
(for example if you set it to 500), you may see messages like</p><div class="panel" style="border-width: 1px;"><div class="panelContent">
-<p>Slow KahaDB access: cleanup took 1277 | org.apache.activemq.store.kahadb.MessageDatabase | ActiveMQ Journal Checkpoint Worker</p>
+</div></div><h3 id="KahaDB-KahaDBProperties">KahaDB Properties</h3><div class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1" class="confluenceTh"><p>property name</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>default value</p></th><th colspan="1" rowspan="1" class="confluenceTh"><p>Comments</p></th></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>archiveCorruptedIndex</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, corrupted indexes found at startup will be archived (not deleted).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>archiveDataLogs</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, will move a message data log to the archive directory instead of deleting it.</p></t
d></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>checkForCorruptJournalFiles</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, will check for corrupted Journal files on startup and try and recover them.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>checkpointInterval</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>5000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Time (ms) before check-pointing the journal.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>checksumJournalFiles</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Create a checksum for a journal file - to enable checking for corrupted journals.</p><p>Before <strong>ActiveMQ 5.9.0</strong>: the default i
s <strong><code>false</code></strong>.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>cleanupInterval</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>30000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Time (ms) before checking for a discarding/moving message data logs that are no longer used.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>compactAcksAfterNoGC</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>10</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.14.0</strong>: when the acknowledgement compaction feature is enabled this value controls how many store GC cycles must be completed with no other files being cleaned up before the compaction logic is triggered to possibly compact older acknowledgements spread across journal files into a new log file.  The lower the value set the faster the compaction may oc
cur which can impact performance if it runs to often.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>compactAcksIgnoresStoreGrowth</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.14.0</strong>: when the acknowledgement compaction feature is enabled this value controls whether compaction is run when the store is still growing or if it should only occur when the store has stopped growing (either due to idle or store limits reached).  If enabled the compaction runs regardless of the store still having room or being active which can decrease overall performance but reclaim space faster. </p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>concurrentStoreAndDispatchQueues</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confl
uenceTd"><p>Enable the dispatching of Queue messages to interested clients to happen concurrently with message storage.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>concurrentStoreAndDispatchTopics</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Enable the dispatching of Topic messages to interested clients to happen concurrently with message storage</p><div class="confluence-information-macro confluence-information-macro-warning"><span class="aui-icon aui-icon-small aui-iconfont-error confluence-information-macro-icon"></span><div class="confluence-information-macro-body">Enabling this property is not recommended.</div></div></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>directory</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>activemq-data</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p
>The path to the directory to use to store the message store data and log files.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>directoryArchive</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>null</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Define the directory to move data logs to when they all the messages they contain have been consumed.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>enableAckCompaction</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.14.0</strong>: this setting controls whether the store will perform periodic compaction of older journal log files that contain only Message acknowledgements.  By compacting these older acknowledgements into new journal log files the older files can be removed freeing space and allowing the message store to
continue to operate without hitting store size limits.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>enableIndexWriteAsync</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If set, will asynchronously write indexes.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>enableJournalDiskSyncs</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Ensure every journal write is followed by a disk sync (JMS durability requirement).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>ignoreMissingJournalfiles</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>If enabled, will ignore a missing message log file.</p></td></tr><tr><td colspan=
"1" rowspan="1" class="confluenceTd"><p><code>indexCacheSize</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>10000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Number of index pages cached in memory.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>indexDirectory</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"> </td><td colspan="1" rowspan="1" class="confluenceTd"><p><span>From <strong>ActiveMQ 5.10.0</strong>: If set, configures where the KahaDB index files (<strong><code>db.data</code></strong> and <strong><code>db.redo</code></strong>) will be stored. If not set, the index files are stored in the directory specified by the <strong><code>directory</code></strong> attribute.</span></p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>indexWriteBatchSize</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="
1" rowspan="1" class="confluenceTd"><p>Number of indexes written in a batch.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>journalMaxFileLength</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>32mb</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>A hint to set the maximum size of the message data logs.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>maxAsyncJobs</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>10000</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>The maximum number of asynchronous messages that will be queued awaiting storage (should be the same as the number of concurrent MessageProducers).</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>preallocationScope</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><code>entire_journal</code></td><td colspan="1" rowspan="1" class="confluenceTd"><
p>From <strong>ActiveMQ 5.14.0</strong>: this setting configures how journal data files are preallocated. The default strategy preallocates the journal file on first use using the appender thread. </p><ul><li><strong><code>entire_journal_async</code></strong> will use preallocate ahead of time in a separate thread.</li><li><strong><code>none</code></strong> disables preallocation.</li></ul><p>On SSD, using <strong><code>entire_journal_async</code></strong> avoids delaying writes pending preallocation on first use.</p><p><strong>Note</strong>: on HDD the additional thread contention for disk has a negative impact. Therefore use the default.</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>preallocationStrategy</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>sparse_file</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>From <strong>ActiveMQ 5.12.0</strong>: This setting configures how the broker will tr
y to preallocate the journal files when a new journal file is needed.</p><ul><li><strong><code>sparse_file</code></strong> - sets the file length, but does not populate it with any data.</li><li><strong><code>os_kernel_copy</code></strong> - delegates the preallocation to the Operating System.</li><li><strong><code>zeros</code></strong>  - each preallocated journal file contains nothing but <strong><code>0x00</code></strong> throughout.</li></ul></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p><code>storeOpenWireVersion</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p><code>11</code></p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Determines the version of OpenWire commands that are marshaled to the KahaDB journal. </p><p>Before <strong>ActiveMQ 5.12.0</strong>: the default value is <strong><code>6</code></strong>.</p><p>Some features of the broker depend on information stored in the OpenWire commands from newer protocol revis
ions and these may not work correctly if the store version is set to a lower value.  KahaDB stores from broker versions greater than 5.9.0 will in many cases still be readable by the broker but will cause the broker to continue using the older store version meaning newer features may not work as intended. </p><p>For KahaDB stores that were created in versions prior to <strong>ActiveMQ 5.9.0</strong> it will be necessary to manually set <strong><code>storeOpenWireVersion="6"</code></strong> in order to start a broker without error.</p></td></tr></tbody></table></div><p>For tuning locking properties please take a look at <a shape="rect" href="pluggable-storage-lockers.html">Pluggable storage lockers</a></p><h3 id="KahaDB-Slowfilesystemaccessdiagnosticlogging">Slow file system access diagnostic logging</h3><p>You can configure a non zero threshold in milliseconds for database updates. If database operation is slower than that threshold (for example if you set it to 500), you
may see messages like</p><div class="panel" style="border-width: 1px;"><div class="panelContent">
+<p><code>Slow KahaDB access: cleanup took 1277 | org.apache.activemq.store.kahadb.MessageDatabase | ActiveMQ Journal Checkpoint Worker</code></p>
</div></div><p>You can configure a threshold used to log these messages by using a system property and adjust it to your disk speed so that you can easily pick up runtime anomalies.</p><div class="panel" style="border-width: 1px;"><div class="panelContent">
-<p>-Dorg.apache.activemq.store.kahadb.LOG_SLOW_ACCESS_TIME=1500</p>
-</div></div><h1 id="KahaDB-Multi(m)kahaDBpersistenceadapter">Multi(m) kahaDB persistence adapter</h1><p>From 5.6, it is possible to distribute destinations stores across multiple kahdb persistence adapters. When would you do this? If you have one fast producer/consumer destination and another periodic producer destination that has irregular batch consumption, you disk usage can grow out of hand because unconsumed messages get dotted across journal files. Having a separate journal for each ensures minimal journal usage. Also, some destination may be critical and require disk synchronization while others may not. In these cases you can use the mKahaDB persistence adapter and filter destinations using wildcards, just like with destination policy entries.</p><h3 id="KahaDB-Transactions">Transactions</h3><p>Transactions can span multiple journals if the destinations are distributed. This means that two phase completion is necessary, which does impose a performance (additional disk sync)
penalty to record the commit outcome. This penalty is only imposed if more than one journal is involved in a transaction.</p><h2 id="KahaDB-Configuration.1">Configuration</h2><p>Each instance of kahaDB can be configured independently. If no destination is supplied to a <strong><code>filteredKahaDB</code>, the implicit default value will match any destination, queue or topic. This is a handy catch all. If no matching persistence adapter can be found, destination creation will fail with an exception. The </strong><code>filteredKahaDB</code> shares its wildcard matching rules with <a shape="rect" href="per-destination-policies.html">Per Destination Policies</a>.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"><broker brokerName="broker" ... >
+<p><code>-Dorg.apache.activemq.store.kahadb.LOG_SLOW_ACCESS_TIME=1500</code></p>
+</div></div><h1 id="KahaDB-Multi(m)kahaDBpersistenceadapter">Multi(m) kahaDB persistence adapter</h1><p>From 5.6, it is possible to distribute destinations stores across multiple kahdb persistence adapters. When would you do this? If you have one fast producer/consumer destination and another periodic producer destination that has irregular batch consumption, you disk usage can grow out of hand because unconsumed messages get dotted across journal files. Having a separate journal for each ensures minimal journal usage. Also, some destination may be critical and require disk synchronization while others may not. In these cases you can use the mKahaDB persistence adapter and filter destinations using wildcards, just like with destination policy entries.</p><h3 id="KahaDB-Transactions">Transactions</h3><p>Transactions can span multiple journals if the destinations are distributed. This means that two phase completion is necessary, which does impose a performance (additional disk sync)
penalty to record the commit outcome. This penalty is only imposed if more than one journal is involved in a transaction.</p><h2 id="KahaDB-Configuration.1">Configuration</h2><p>Each instance of kahaDB can be configured independently. If no destination is supplied to a <strong><code>filteredKahaDB</code></strong>, the implicit default value will match any destination, queue or topic. This is a handy catch all. If no matching persistence adapter can be found, destination creation will fail with an exception. The <strong><code>filteredKahaDB</code></strong> shares its wildcard matching rules with <a shape="rect" href="per-destination-policies.html">Per Destination Policies</a>.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<pre class="brush: xml; gutter: false; theme: Default" style="font-size:12px;"><broker brokerName="broker" ... >
<persistenceAdapter>
<mKahaDB directory="${activemq.base}/data/kahadb">
<filteredPersistenceAdapters>
@@ -120,8 +119,8 @@
...
</broker>
</pre>
-</div></div><h3 id="KahaDB-Automaticperdestinationpersistenceadapter">Automatic per destination persistence adapter</h3><p>When the <code>perDestination</code> boolean attribute is set to true on the catch all (no explicit destination set), <code>filteredKahaDB</code>. Each matching destination will get its own <code>kahaDB</code> instance.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;"><broker brokerName="broker" ... >
+</div></div><h3 id="KahaDB-Automaticperdestinationpersistenceadapter">Automatic per destination persistence adapter</h3><p>When the <strong><code>perDestination</code></strong> boolean attribute is set to true on the catch all (no explicit destination set), <strong><code>filteredKahaDB</code></strong>. Each matching destination will get its own <strong><code>kahaDB</code></strong> instance.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<pre class="brush: xml; gutter: false; theme: Default" style="font-size:12px;"><broker brokerName="broker" ... >
<persistenceAdapter>
<mKahaDB directory="${activemq.base}/data/kahadb">
<filteredPersistenceAdapters>
@@ -137,7 +136,7 @@
...
</broker>
</pre>
-</div></div><div class="confluence-information-macro confluence-information-macro-information"><p class="title">Note:</p><span class="aui-icon aui-icon-small aui-iconfont-info confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>Specifying</p><pre>perDestination="true" and queue=">"</pre><p>on the same line has not been verified to work and may result in</p><pre>Reason: java.io.IOException: File '/opt/java/apache-activemq-5.9.0/data/mKahaDB/lock' could not be locked as lock is already held for this jvm. </pre></div></div></div>
+</div></div><div class="confluence-information-macro confluence-information-macro-information"><p class="title">Note:</p><span class="aui-icon aui-icon-small aui-iconfont-info confluence-information-macro-icon"></span><div class="confluence-information-macro-body"><p>Specifying: <strong><code>perDestination="true"</code></strong> and <strong><code>queue=">"</code></strong> on the same line has not been verified to work and may result in:</p><p> </p><pre>Reason: java.io.IOException: File '/opt/java/apache-activemq-5.9.0/data/mKahaDB/lock' could not be locked as lock is already held for this jvm. </pre></div></div></div>
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