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  1. Documentation
  2. DOCS-4484

Document that mongoS no longer pins connections to secondaries

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Details

    • Improvement
    • Status: Closed
    • Major - P3
    • Resolution: Done
    • None
    • v1.3.16, mongodb-2.6, mongodb-3.0
    • manual
    • None
    • 8

    Description

      As of server 2.8 and server 2.6.4, mongoS no longer pins secondary connections to allow changes in read preferences between queries.

      Special attention, from ticket: "As these changes could not be backported to 2.6, a different fix was implemented specifically for 2.6: a new mongos server parameter, internalDBClientRSReselectNodePercentage was introduced. This can be set to any value from 0 to 100 (defaults to 0) and represents the probability (expressed in percentage) of a replica set connection in mongos to reevaluate replica set node selection from scratch, regardless of the compatibility of the current read preference to the last-used secondary node. Extra care should be taken since reselecting a replica set node will destroy the old connection and create a new connection. This means in extreme cases (for example, 100%), mongos can be creating and destroying connections for every read request."

      Text re: pinning at http://docs.mongodb.org/manual/core/read-preference-mechanics/ should be changed.

      See linked.

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              sam.kleinman Sam Kleinman (Inactive)
              michael.paik Michael Paik
              Jess Mokrzecki Jess Mokrzecki
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              Dates

                Created:
                Updated:
                Resolved:
                8 years, 42 weeks ago