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  1. HBase
  2. HBASE-12070

Add an option to hbck to fix ZK inconsistencies

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 1.0.1, 1.1.0, 0.98.11
    • Fix Version/s: 1.0.0, 1.1.0, 0.98.11
    • Component/s: hbck
    • Labels:
      None
    • Hadoop Flags:
      Reviewed
    • Release Note:
      Adds a new option to HBCK tool -fixOrphanedTableZnodes, which fixes orphaned table entries in zookeeper which does not have corresponding meta entries. This state can be from a failed create table attempt.

      Description

      If the HMaster bounces in the middle of table creation, we could be left in a state where a znode exists for the table, but that hasn't percolated into META or to HDFS. We've run into this a couple times on our clusters. Once the table is in this state, the only fix is to rm the znode using the zookeeper-client. Doing this manually looks a bit error prone. Could an option be added to hbck to catch and fix such inconsistencies?

      A more general issue I'd like comment on is whether it makes sense for HMaster to be maintaining its own write-ahead log? The idea would be that on a bounce, the master would discover it was in the middle of creating a table and either rollback or complete that operation? An issue that we observed recently was that a table that was in DISABLING state before a bounce was not in that state after. A write-ahead log to persist table state changes seems useful. Now, all of this state could be in ZK instead of the WAL - it doesn't matter where it gets persisted as long as it does.

        Attachments

        1. HBASE-12070.v1-branch-1.patch
          19 kB
          Stephen Yuan Jiang
        2. HBASE-12070.v2-branch-1.patch
          20 kB
          Stephen Yuan Jiang
        3. HBASE-12070.v1-0.98.patch
          16 kB
          Stephen Yuan Jiang

          Activity

            People

            • Assignee:
              syuanjiang Stephen Yuan Jiang
              Reporter:
              skadambi Sudarshan Kadambi
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              Dates

              • Created:
                Updated:
                Resolved: