[OAK-3733] Sometimes hierarchy conflict between concurrent add/delete isn't detected

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0.26, 1.2.10, 1.3.13, 1.4
• Component/s: core, documentmk
• Assignee: Marcel Reutegger
• Reporter: Vikas Saurabh
• Created: 06/Dec/15 16:15
• Updated: 02/Mar/16 15:09
• Resolved: 16/Dec/15 13:38

Description

I'm not sure of exact set of event that led to an incident on one of our test clusters. The cluster is running 3 AEM instances based on oak build at 1.3.10.r1713699 backed by a single mongo 3 instance.

Unfortunately, we found the issue too late and logs had rolled over. Here's the exception that showed over and over as workflow jobs were (trying to) being processed:

....
        at java.lang.Thread.run(Thread.java:745)
Caused by: javax.jcr.InvalidItemStateException: OakMerge0004: OakMerge0004: The node 8:/oak:index/event.job.topic/:index/com%2Fadobe%2Fgranite%2Fworkflow%2Ftransient%2Fjob%2Fetc%2Fworkflow%2Fmodels%2Fdam-xmp-writeback%2Fjcr_content%2Fmodel/var/eventing/jobs/assigned was already added in revision
r151233e54e1-0-4, before
r15166378b6a-0-2 (retries 5, 6830 ms)
        at org.apache.jackrabbit.oak.api.CommitFailedException.asRepositoryException(CommitFailedException.java:239)
        at org.apache.jackrabbit.oak.api.CommitFailedException.asRepositoryException(CommitFailedException.java:212)
        at org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.newRepositoryException(SessionDelegate.java:669)
        at org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.save(SessionDelegate.java:495)
        at org.apache.jackrabbit.oak.jcr.session.SessionImpl$8.performVoid(SessionImpl.java:419)
        at org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.performVoid(SessionDelegate.java:273)
        at org.apache.jackrabbit.oak.jcr.session.SessionImpl.save(SessionImpl.java:416)
        at org.apache.sling.jcr.resource.internal.helper.jcr.JcrResourceProvider.commit(JcrResourceProvider.java:634)
        ... 16 common frames omitted
Caused by: org.apache.jackrabbit.oak.api.CommitFailedException: OakMerge0004: OakMerge0004: The node 8:/oak:index/event.job.topic/:index/com%2Fadobe%2Fgranite%2Fworkflow%2Ftransient%2Fjob%2Fetc%2Fworkflow%2Fmodels%2Fdam-xmp-writeback%2Fjcr_content%2Fmodel/var/eventing/jobs/assigned was already added in revision
r151233e54e1-0-4, before
r15166378b6a-0-2 (retries 5, 6830 ms)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.merge0(DocumentNodeStoreBranch.java:200)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.merge(DocumentNodeStoreBranch.java:123)
        at org.apache.jackrabbit.oak.plugins.document.DocumentRootBuilder.merge(DocumentRootBuilder.java:158)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStore.merge(DocumentNodeStore.java:1497)
        at org.apache.jackrabbit.oak.core.MutableRoot.commit(MutableRoot.java:247)
        at org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.commit(SessionDelegate.java:346)
        at org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.save(SessionDelegate.java:493)
        ... 20 common frames omitted
Caused by: org.apache.jackrabbit.oak.plugins.document.ConflictException: The node 8:/oak:index/event.job.topic/:index/com%2Fadobe%2Fgranite%2Fworkflow%2Ftransient%2Fjob%2Fetc%2Fworkflow%2Fmodels%2Fdam-xmp-writeback%2Fjcr_content%2Fmodel/var/eventing/jobs/assigned was already added in revision
r151233e54e1-0-4, before
r15166378b6a-0-2
        at org.apache.jackrabbit.oak.plugins.document.Commit.checkConflicts(Commit.java:582)
        at org.apache.jackrabbit.oak.plugins.document.Commit.createOrUpdateNode(Commit.java:487)
        at org.apache.jackrabbit.oak.plugins.document.Commit.applyToDocumentStore(Commit.java:371)
        at org.apache.jackrabbit.oak.plugins.document.Commit.applyToDocumentStore(Commit.java:265)
        at org.apache.jackrabbit.oak.plugins.document.Commit.applyInternal(Commit.java:234)
        at org.apache.jackrabbit.oak.plugins.document.Commit.apply(Commit.java:219)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.persist(DocumentNodeStoreBranch.java:290)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.persist(DocumentNodeStoreBranch.java:260)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.access$300(DocumentNodeStoreBranch.java:54)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch$InMemory.merge(DocumentNodeStoreBranch.java:498)
        at org.apache.jackrabbit.oak.plugins.document.DocumentNodeStoreBranch.merge0(DocumentNodeStoreBranch.java:180)
        ... 26 common frames omitted
....

Doing following removed repo corruption and restored w/f processing:

oak.removeDescendantsAndSelf("/oak:index/event.job.topic/:index/com%2Fadobe%2Fgranite%2Fworkflow%2Ftransient%2Fjob%2Fetc%2Fworkflow%2Fmodels%2Fdam-xmp-writeback%2Fjcr_content%2Fmodel/var/eventing/jobs/assigned")

Attaching mongoexport output for /oak:index/event.job.topic/:index/com%2Fadobe%2Fgranite%2Fworkflow%2Ftransient%2Fjob%2Fetc%2Fworkflow%2Fmodels%2Fdam-xmp-writeback%2Fjcr_content%2Fmodel/var/eventing/jobs/assigned/6a389a6a-a8bf-4038-b57b-cb441c6ac557/com.adobe.granite.workflow.transient.job.etc.workflow.models.dam-xmp-writeback.jcr_content.model/2015/11/19/23/54/6a389a6a-a8bf-4038-b57b-cb441c6ac557_10 (the hierarchy created at r151233e54e1-0-4). I've renamed a few path elements to make it more reable though (e.g. :index/com%2Fadobe%2Fgranite%2Fworkflow%2Ftransient%2Fjob%2Fetc%2Fworkflow%2Fmodels%2Fdam-xmp-writeback%2Fjcr_content%2Fmodel -> enc_value).

mreutegg, I'm assigning it to myself for now, but I think this would require your expertise all the way .

Issue Links

• relates to: OAK-3028 Hierarchy conflict detection broken
• relates to: OAK-2929 Parent of unseen children must not be removable