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  1. Core Server
  2. SERVER-31010

Server Selection localThresholdMS enhancement

    • Type: Icon: New Feature New Feature
    • Resolution: Won't Do
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: None
    • Component/s: Replication
    • None
    • Service Arch

      From the documentation

      _When localThresholdMS is used :
      During monitoring, drivers regularly record the RTT of ismaster commands. The Server Selection specification calls for these to be calculated using an exponentially-weighted moving average function.

      If the prior average is denoted RTTt-1, then the new average (RTTt) is computed from a new RTT measurement (Xt) and a weighting factor (α) using the following formula:

        t = α·Xt + (1-α)·RTTt-1

      The weighting factor is set to 0.2, which was chosen to put about 85% of the weight of the average RTT on the 9 most recent observations. Weighting recent observations more means that the average responds quickly to sudden changes in latency._

      Would it be possible to have another similar configuration option to tell the client to observe query/operation response times over a window of time or over n executions, be able to specify a threshold for response times so that servers with best response times can be picked over slow responding servers?

            backlog-server-servicearch [DO NOT USE] Backlog - Service Architecture
            shakir.sadikali@mongodb.com Shakir Sadikali
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