A SegmentNotFoundException is observed in the log files. Restarting AEM makes the error go away for one day (or longer).
For example:
29.09.2017 05:40:27.031 *ERROR* [10.40.228.155 [1506663627021] GET /services/createvaultpackage HTTP/1.1] org.apache.jackrabbit.oak.segment.SegmentNotFoundExceptionListener Segment not found: 6c3c7910-6501-4c0a-af5d-6972006c6145. SegmentId age=654602216ms,segment-generation=17 org.apache.jackrabbit.oak.segment.SegmentNotFoundException: Segment 6c3c7910-6501-4c0a-af5d-6972006c6145 not found at org.apache.jackrabbit.oak.segment.file.FileStore$8.call(FileStore.java:602) ... at org.apache.jackrabbit.oak.plugins.nodetype.ReadOnlyNodeTypeManager.internalGetNodeType(ReadOnlyNodeTypeManager.java:409) at org.apache.jackrabbit.oak.plugins.nodetype.ReadOnlyNodeTypeManager.getNodeType(ReadOnlyNodeTypeManager.java:147) at org.apache.jackrabbit.vault.packaging.impl.JcrPackageManagerImpl.initNodeTypes(JcrPackageManagerImpl.java:737) at org.apache.jackrabbit.vault.packaging.impl.JcrPackageManagerImpl.(JcrPackageManagerImpl.java:109) at org.apache.jackrabbit.vault.packaging.PackagingService.getPackageManager(PackagingService.java:49) at customcode.VaultPackageFromSearchServlet.doGet(VaultPackageFromSearchServlet.java:172)
Avoid keeping JCR sessions open for a long time. To resolve the issue:
- Close the session and open a new one when required.
- Or periodically call session.refresh(true).
See this article for more details on the topic of long running sessions being an anti-pattern in AEM 6.x.