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  1. Core Server
  2. SERVER-45953

Exempt oplog readers from acquiring read tickets

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Details

    • Bug
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • 4.7.0, 4.4.11, 4.2.18, 4.0.28
    • Storage
    • None
    • Fully Compatible
    • v4.4, v4.2, v4.0
    • Execution Team 2020-05-18, Execution Team 2020-06-01, Execution Team 2020-06-15

    Description

      There are certain operations on the system that depend on the ability to replicate oplog entries in order to make progress. Today, secondaries reading the oplog on their sync sources can be blocked by read ticket exhaustion, potentially creating deadlocks. In order to break this deadlock situation, we can exempt oplog read queries from needing to acquire read tickets.
      One good way to determine if a reader is an oplog reader from a downstream node is to use the isReplOplogFetching flag.

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              dianna.hohensee@mongodb.com Dianna Hohensee
              milkie@mongodb.com Eric Milkie
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                Created:
                Updated:
                Resolved: