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  1. WiredTiger
  2. WT-4095

Review log slot switch algorithm to reduce lock contention

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    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major - P3
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: Backlog
    • Component/s: None
    • Labels:
      None
    • Sprint:
      Storage Non-NYC 2018-06-04

      Description

      The current log slot switching algorithm holds the slot lock while writing the content out to filesystem. That's necessary because a forced flush can come in, and it relies on an acquisition of the slot lock to indicate that any data in a slot has been written.

      If we could make a change to the forced flush algorithm so that it no longer relies on the write happening inside the lock, we could remove a point of contention in our logging algorithm that is noticeable when the log is written on a slow filesystem.

      This is related to WT-4058 and WT-4077. Those tickets have more complete description of a first attempt at this optimization, and the race condition it introduced.

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              Assignee:
              backlog-server-storage-engines Backlog - Storage Engines Team
              Reporter:
              alexander.gorrod Alexander Gorrod
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                Created:
                Updated: