Alex Ivanov created HDFS-9052:
---------------------------------
Summary: deleteSnapshot runs into AssertionError
Key: HDFS-9052
URL: https://issues.apache.org/jira/browse/HDFS-9052
Project: Hadoop HDFS
Issue Type: Bug
Reporter: Alex Ivanov
CDH 5.0.5 upgraded from CDH 5.0.0 (Hadoop 2.3)
Upon deleting a snapshot, we run into the following assertion error. The
scenario is as follows:
1. We have a program that deletes snapshots in reverse chronological order.
2. The program deletes a couple of hundred snapshots successfully but runs into
the following exception:
java.lang.AssertionError: Element already exists:
element=useraction.log.crypto, DELETED=[useraction.log.crypto]
3. There seems to be an issue with that snapshot, which causes a file, which
normally gets overwritten in every snapshot to be added to the SnapshotDiff
delete queue twice.
4. Once the deleteSnapshot is run on the problematic snapshot, if the Namenode
is restarted, it cannot be started again until the transaction is removed from
the EditLog.
5. Sometimes the bad snapshot can be deleted but the prior snapshot seems to
"inherit" the same issue.
6. The error below is from Namenode starting when the DELETE_SNAPSHOT
transaction is replayed from the EditLog.
2015-09-01 22:59:59,140 INFO [IPC Server handler 0 on 8022] BlockStateChange
(BlockManager.java:logAddStoredBlock(2342)) - BLOCK* addStoredBlock: blockMap
updated: 10.52.209.77:1004 is added to
blk_1080833995_7093259{blockUCState=UNDER_CONSTRUCTION, primaryNodeIndex=-1,
replicas=[ReplicaUnderConstruction[[DISK]DS-16de62e5-f6e2-4ea7-aad9-f8567bded7d7:NORMAL|FINALIZED]]}
size 0
2015-09-01 22:59:59,140 INFO [IPC Server handler 0 on 8022] BlockStateChange
(BlockManager.java:logAddStoredBlock(2342)) - BLOCK* addStoredBlock: blockMap
updated: 10.52.209.77:1004 is added to
blk_1080833996_7093260{blockUCState=UNDER_CONSTRUCTION, primaryNodeIndex=-1,
replicas=[ReplicaUnderConstruction[[DISK]DS-1def2b07-d87f-49dd-b14f-ef230342088d:NORMAL|FINALIZED]]}
size 0
2015-09-01 22:59:59,141 ERROR [IPC Server handler 0 on 8022]
namenode.FSEditLogLoader (FSEditLogLoader.java:loadEditRecords(232)) -
Encountered exception on operation DeleteSnapshotOp
[snapshotRoot=/data/tenants/pdx-svt.baseline84/wddata,
snapshotName=s2015022614_maintainer_soft_del,
RpcClientId=7942c957-a7cf-44c1-880d-6eea690e1b19, RpcCallId=1]
2015-09-01 22:59:59,141 ERROR [IPC Server handler 0 on 8022]
namenode.FSEditLogLoader (FSEditLogLoader.java:loadEditRecords(232)) -
Encountered exception on operation DeleteSnapshotOp
[snapshotRoot=/data/tenants/pdx-svt.baseline84/wddata,
snapshotName=s2015022614_maintainer_soft_del,
RpcClientId=7942c957-a7cf-44c1-880d-6eea690e1b19, RpcCallId=1]
java.lang.AssertionError: Element already exists:
element=useraction.log.crypto, DELETED=[useraction.log.crypto]
at org.apache.hadoop.hdfs.util.Diff.insert(Diff.java:193)
at org.apache.hadoop.hdfs.util.Diff.delete(Diff.java:239)
at org.apache.hadoop.hdfs.util.Diff.combinePosterior(Diff.java:462)
at
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature$DirectoryDiff$2.initChildren(DirectoryWithSnapshotFeature.java:293)
at
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature$DirectoryDiff$2.iterator(DirectoryWithSnapshotFeature.java:303)
at
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.cleanDeletedINode(DirectoryWithSnapshotFeature.java:531)
at
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.cleanDirectory(DirectoryWithSnapshotFeature.java:823)
at
org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtree(INodeDirectory.java:714)
at
org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtreeRecursively(INodeDirectory.java:684)
at
org.apache.hadoop.hdfs.server.namenode.snapshot.DirectoryWithSnapshotFeature.cleanDirectory(DirectoryWithSnapshotFeature.java:830)
at
org.apache.hadoop.hdfs.server.namenode.INodeDirectory.cleanSubtree(INodeDirectory.java:714)
at
org.apache.hadoop.hdfs.server.namenode.snapshot.INodeDirectorySnapshottable.removeSnapshot(INodeDirectorySnapshottable.java:341)
at
org.apache.hadoop.hdfs.server.namenode.snapshot.SnapshotManager.deleteSnapshot(SnapshotManager.java:238)
at
org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.applyEditLogOp(FSEditLogLoader.java:667)
at
org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadEditRecords(FSEditLogLoader.java:224)
at
org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader.loadFSEdits(FSEditLogLoader.java:133)
at
org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:802)
at
org.apache.hadoop.hdfs.server.namenode.FSImage.loadEdits(FSImage.java:783)
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