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  1. WiredTiger
  2. WT-6513

Update history store configuration to make overflow keys unlikely

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Details

    • Improvement
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • WT10.0.0, 4.9.0, 4.4.5
    • None
    • None
    • 5
    • Storage - Ra 2021-01-25, Storage - Ra 2021-02-08, Storage - Ra 2021-02-22

    Description

      Our current History Store create configuration string is:

      "key_format="IuQQ",value_format="QQQu",block_compressor="WT_HS_COMPRESSOR                                     ",leaf_value_max=64MB,prefix_compression=false"
      

      We should update the configuration to make it very unlikely that we'll ever use overflow keys in the history store. Probably by setting leaf_key_max and internal_key_max to the same value as leaf_value_max.

      The default value is 1/10th of a page split size. The default page size is 4KB meaning that the overflow size is about 400 bytes. MongoDB could definitely be triggering that with indexes at the moment.

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              sulabh.mahajan@mongodb.com Sulabh Mahajan
              alexander.gorrod@mongodb.com Alexander Gorrod
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                Created:
                Updated:
                Resolved: