[OAK-3099] Revision GC fails when split documents with very long paths are present

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.0.13
• Fix Version/s: 1.0.18, 1.2.3, 1.3.3, 1.4
• Component/s: mongomk
• Assignee: Amit Jain
• Reporter: Csaba Varga
• Created: 14/Jul/15 08:58
• Updated: 02/Mar/16 11:55
• Resolved: 16/Jul/15 04:08

Description

My company is using the MongoDB microkernel with Oak, and we've noticed that the daily revision GC is failing with errors like this:

13.07.2015 13:06:16.261 *ERROR* [pool-7-thread-1-Maintenance Queue(com/adobe/granite/maintenance/job/RevisionCleanupTask)] org.apache.jackrabbit.oak.management.ManagementOperation Revision garbage collection failed
java.lang.IllegalArgumentException: 13:h113f9d0fe7ac0f87fa06397c37b9ffd4b372eeb1ec93e0818bb4024a32587820
at org.apache.jackrabbit.oak.plugins.document.Revision.fromString(Revision.java:236)
at org.apache.jackrabbit.oak.plugins.document.SplitDocumentCleanUp.disconnect(SplitDocumentCleanUp.java:84)
at org.apache.jackrabbit.oak.plugins.document.SplitDocumentCleanUp.disconnect(SplitDocumentCleanUp.java:56)
at org.apache.jackrabbit.oak.plugins.document.VersionGCSupport.deleteSplitDocuments(VersionGCSupport.java:53)
at org.apache.jackrabbit.oak.plugins.document.VersionGarbageCollector.collectSplitDocuments(VersionGarbageCollector.java:117)
at org.apache.jackrabbit.oak.plugins.document.VersionGarbageCollector.gc(VersionGarbageCollector.java:105)
at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreService$2.run(DocumentNodeStoreService.java:511)
at org.apache.jackrabbit.oak.spi.state.RevisionGC$1.call(RevisionGC.java:68)
at org.apache.jackrabbit.oak.spi.state.RevisionGC$1.call(RevisionGC.java:64)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

I've narrowed the issue down to the disconnect(NodeDocument) method of the SplitDocumentCleanUp class. The method always tries to extract the path of the node from its ID, but this won't work for documents whose path is very long because those documents will have the hash of their path in the ID.

I believe this code should fix the issue, but I haven't had a chance to actually try it:

    private void disconnect(NodeDocument splitDoc) {
        String mainId = Utils.getIdFromPath(splitDoc.getMainPath());
        NodeDocument doc = store.find(NODES, mainId);
        if (doc == null) {
            LOG.warn("Main document {} already removed. Split document is {}",
                    mainId, splitId);
            return;
        }
        String path = splitDoc.getPath();
        int slashIdx = path.lastIndexOf('/');
        int height = Integer.parseInt(path.substring(slashIdx + 1));
        Revision rev = Revision.fromString(
                path.substring(path.lastIndexOf('/', slashIdx - 1) + 1, slashIdx));
        doc = doc.findPrevReferencingDoc(rev, height);
        if (doc == null) {
            LOG.warn("Split document {} not referenced anymore. Main document is {}",
                    splitId, mainId);
            return;
        }
        // remove reference
        if (doc.getSplitDocType() == INTERMEDIATE) {
            disconnectFromIntermediate(doc, rev);
        } else {
            markStaleOnMain(doc, rev, height);
        }
    }

By using getPath(), the code should automatically use either the ID or the _path property, whichever is right for the document.