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  1. Cassandra
  2. CASSANDRA-16552

Anticompaction appears to race with Compaction, preventing forward compaction progress after an incremental repair

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    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: High
    • Resolution: Fixed
    • Fix Version/s: 4.0-rc1, 4.0
    • Component/s: Local/Compaction
    • Labels:
      None

      Description

      While testing 4.0-rc1 on a 12 i3en.2xlarge x 2 region (AWS us-east-1 and eu-west-1) cluster I attempted to run nodetool repair while the cluster was taking moderate read/write load.

      The first time it worked as expected, but when I ran an incremental run the second time multiple nodes got stuck trying to compact the unrepaired sstables. They are now spinning with:

      $ nt compactionstats
      pending tasks: 827
      - acceptance_josephl.acceptance_josephl_cass4: 827
      
      $ nt tpstats            
      Pool Name                    Active Pending Completed Blocked All time blocked
      RequestResponseStage         0      0       422359133 0       0               
      MutationStage                0      0       164540628 0       0               
      ReadStage                    0      0       198857844 0       0               
      CompactionExecutor           0      0       60782     0       0    
      
      
      $ tail system.log
      DEBUG [CompactionExecutor:684] 2021-03-31 15:13:59,902 LeveledManifest.java:292 - L0 is too far behind, performing size-tiering there first
      DEBUG [CompactionExecutor:684] 2021-03-31 15:13:59,908 LeveledManifest.java:292 - L0 is too far behind, performing size-tiering there first
      WARN  [CompactionExecutor:684] 2021-03-31 15:13:59,912 LeveledCompactionStrategy.java:154 - Could not acquire references for compacting SSTables [BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11eba
      fb40b81cbd6fb3d/na-4826-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4872-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acc
      eptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4849-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4874-big-Data.db'), BigTableReader(path='/mnt/dat
      a/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4841-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4897-big-D
      ata.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4924-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e79
      0917c11ebafb40b81cbd6fb3d/na-4837-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4926-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_j
      osephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4729-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4723-big-Data.db'), BigTableReader(path
      ='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4875-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-
      4922-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4920-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cas
      s4-6144e790917c11ebafb40b81cbd6fb3d/na-4869-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4823-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/ac
      ceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4846-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4873-big-Data.db'), BigTableR
      eader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4840-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cb
      d6fb3d/na-4833-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4829-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_j
      osephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4726-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4923-big-Data.db'), BigTableReader(path='/mnt/data/cassand
      ra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4925-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4905-big-Data.db'),
      BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4876-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11eb
      afb40b81cbd6fb3d/na-4901-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4732-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/ac
      ceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4909-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4915-big-Data.db'), BigTableReader(path='/mnt/da
      ta/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4921-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4860-big-
      Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4693-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e7
      90917c11ebafb40b81cbd6fb3d/na-4694-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4692-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_
      josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4691-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4696-big-Data.db'), BigTableReader(pat
      h='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4697-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na
      -4700-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4698-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_ca
      ss4-6144e790917c11ebafb40b81cbd6fb3d/na-4688-big-Data.db'), BigTableReader(path='/mnt/data/cassandra/data/acceptance_josephl/acceptance_josephl_cass4-6144e790917c11ebafb40b81cbd6fb3d/na-4689-big-Data.db')] which is not a problem per se,unless it happens
      frequently, in which case it must be reported. Will retry later.
      

      I've attached some starting breadcrumbs. I believe the issue is a potential race in marking sstables for compaction getting null back from tryModify which I think can only happen under a small number of circumstances. From the initial investigation it does appear that only the unrepaired products get into this state.

      I have a heap dump containing the View state but it contains potentially sensitive infrastructure details so if you're debugging just message me in slack and I can send it to you directly.

      The following mitigation appears to unstick the nodes via a forced full compaction:

      nodetool stop COMPACTION; nodetool compact <ks> <table>
      

      I'm not confident in this mitigation though.

        Attachments

        1. anticompaction_before_issue.txt
          12 kB
          Joey Lynch
        2. CompactionStuck.png
          57 kB
          Joey Lynch
        3. CurrentView.png
          282 kB
          Joey Lynch
        4. debug.log.gz
          703 kB
          Joey Lynch
        5. NeighborsFallingBehind.png
          137 kB
          Joey Lynch
        6. system.log.gz
          363 kB
          Joey Lynch

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              • Assignee:
                marcuse Marcus Eriksson
                Reporter:
                jolynch Joey Lynch
                Authors:
                Marcus Eriksson
                Reviewers:
                Benedict Elliott Smith
              • Votes:
                1 Vote for this issue
                Watchers:
                10 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: