OrientDB OByteBufferPool Error
<p>I have just upgraded OrientDB from <strong>2.1.19</strong> to <strong>2.2-rc1</strong> as a result of <a href="https://stackoverflow.com/questions/37077040/stable-jvm-but-system-memory-increase">this issue</a>. </p>

<p>As a recap, I'm running OrientDB in embedded <code>plocal</code> and the application is being launched with the following settings (only included relevant ones):</p>

<pre><code>java -d64 -Xmx2G -Dstorage.diskCache.bufferSize=10000 -server -XX:+AggressiveOpts -XX:CompileThreshold=200 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=${LOG_PATH}/heapdump.hprof -jar app start
</code></pre>

<p>The application launches and initially everything works great. However after a little while I get the following error:</p>

<pre><code>Caused by: java.lang.NullPointerException: null
        at com.orientechnologies.common.directmemory.OByteBufferPool.acquireDirect(OByteBufferPool.java:269)
        at com.orientechnologies.orient.core.storage.cache.local.OWOWCache.cacheFileContent(OWOWCache.java:1206)
        at com.orientechnologies.orient.core.storage.cache.local.OWOWCache.load(OWOWCache.java:617)
        at com.orientechnologies.orient.core.storage.cache.local.twoq.O2QCache.updateCache(O2QCache.java:1224)
        at com.orientechnologies.orient.core.storage.cache.local.twoq.O2QCache.doLoad(O2QCache.java:447)
        at com.orientechnologies.orient.core.storage.cache.local.twoq.O2QCache.load(O2QCache.java:392)
        at com.orientechnologies.orient.core.storage.impl.local.paginated.base.ODurableComponent.loadPage(ODurableComponent.java:150)
        at com.orientechnologies.orient.core.storage.impl.local.paginated.OPaginatedCluster.readRecordNoLock(OPaginatedCluster.java:649) 
        at com.orientechnologies.orient.core.storage.impl.local.paginated.OPaginatedCluster.readRecord(OPaginatedCluster.java:622)
        at com.orientechnologies.orient.core.storage.impl.local.OAbstractPaginatedStorage.doReadRecord(OAbstractPaginatedStorage.java:3163)
        at com.orientechnologies.orient.core.storage.impl.local.OAbstractPaginatedStorage.readRecord(OAbstractPaginatedStorage.java:2805)
        at com.orientechnologies.orient.core.storage.impl.local.OAbstractPaginatedStorage.readRecord(OAbstractPaginatedStorage.java:1023)
        at com.orientechnologies.orient.core.db.document.ODatabaseDocumentTx$SimpleRecordReader.readRecord(ODatabaseDocumentTx.java:3168)
        at com.orientechnologies.orient.core.db.document.ODatabaseDocumentTx.executeReadRecord(ODatabaseDocumentTx.java:1824)
</code></pre>

<p>Once the error has occurred <strong>some queries</strong> stop working. I'm guessing the error is originating from a lack of native memory. Does anybody have any insight as to what specifically is causing this and how to prevent it. I can allocate more memory if needed. I'm just not sure the <em>type</em> of memory to allocate.</p>