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  1. Core Server
  2. SERVER-42343

WiredTigerLAS.wt grows when lagged node is in maintenance mode

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Details

    • Bug
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • 3.4.20
    • 3.4.23
    • None
    • None
    • Fully Compatible
    • ALL
    • Execution Team 2019-07-29, Execution Team 2019-08-12, Execution Team 2019-08-26

    Description

      As part of rolling index builds and similar operations, we'll often take nodes offline for O(hours). When the node comes back online, we'll put it into maintenance mode (using replSetMaintenance) until the node catches back up. We've observed that such nodes often end up with a huge WiredTigerLAS.wt file. We've done some investigation and it seems to be the case that this only happens when we put the node into maintenance mode; if we simply let a lagged node stay in secondary mode, we don't see WiredTigerLAS.wt grow.

      We suspect this is related to cache pressure of majority read concern since we only started seeing these issues when we enabled that.

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          is related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-30638 Change setReadFromMajorityCommittedSnapshot to use the current majority timestamp

          • Major - P3 - Major loss of function.
          • Closed

          Task - A task that needs to be done. SERVER-19209 Need to drop all storage snapshots on rs resync

          • Major - P3 - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-18022 Support "read committed" isolation level where "committed" means confirmed by the voting majority of a replica set

          • Major - P3 - Major loss of function.
          • Closed

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            People

              benety.goh@mongodb.com Benety Goh
              bartle David Bartley
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                Updated:
                Resolved: