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  1. WiredTiger
  2. WT-3012

Test format hanging on LSM configurations

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Details

    • Bug
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • WT2.9.0, 3.2.12, 3.4.0-rc4
    • None
    • None
    • Storage 2016-11-21

    Description

      After the changes in WT-3009, there have been a number of stuck cache aborts on test format runs that use LSM.

      These are reproducible fairly quickly (under 50 runs) on Linux with configs such as below

      ############################################
      #  RUN PARAMETERS
      ############################################
      abort=0
      auto_throttle=1
      backups=0
      bitcnt=6
      bloom=1
      bloom_bit_count=45
      bloom_hash_count=31
      bloom_oldest=0
      cache=30
      checkpoints=1
      checksum=uncompressed
      chunk_size=1
      compaction=0
      compression=zlib
      data_extend=0
      data_source=lsm
      delete_pct=14
      dictionary=0
      direct_io=0
      encryption=none
      evict_max=4
      file_type=row-store
      firstfit=0
      huffman_key=0
      huffman_value=0
      in_memory=0
      insert_pct=73
      internal_key_truncation=0
      internal_page_max=10
      isolation=random
      key_gap=12
      key_max=64
      key_min=26
      leaf_page_max=17
      leak_memory=0
      logging=1
      logging_archive=0
      logging_compression=none
      logging_prealloc=0
      long_running_txn=0
      lsm_worker_threads=4
      merge_max=17
      mmap=1
      ops=100000
      prefix_compression=1
      prefix_compression_min=6
      quiet=1
      repeat_data_pct=29
      reverse=0
      rows=100000
      runs=1
      rebalance=1
      salvage=1
      split_pct=85
      statistics=1
      statistics_server=0
      threads=11
      timer=20
      transaction-frequency=36
      value_max=1638
      value_min=15
      verify=1
      wiredtiger_config=
      write_pct=42
      ############################################
      

      One solution is to modify the changes to the evict trigger setting changed in WT-3009. The more correct option is likely to change how dirty page accounting works in LSM. Currently dirty pages on the primary LSM chunk are counted towards the dirty page total. As these dirty pages are fully expected, capped in size and dealt with by LSM merges they can potentially be removed from the count.

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              michael.cahill@mongodb.com Michael Cahill
              david.hows David Hows
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                Created:
                Updated:
                Resolved: