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  1. Documentation
  2. DOCS-13363

Investigate changes in SERVER-45439: Add support for per operation hedging via an explicit read preference

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    Description

      Description

      Downstream Change Summary

      This ticket introduced a new $readPreference key "hedge" with two subkeys: "enabled" (default true) and "delay" (default true) . (Removed delay in DOCS-13429)

      Description of Linked Ticket

      Add support for operation hedging, as in SERVER-45432, with an explicit readPreference.

      The form of that readpreference should be:

      // some existing command
      		 
      {
      		 
        ...,
      		 
        $readPreference: {
      		 
          mode: "nearest",
      		 
          hedge: {
      		 
            enabled: true,   // default value is true
      		 
            delay: true,        // default value is true
      		 
          }
      		 
      }

      which should map to RemoteCommandRequestOnAny::HedgeOptions of

      • count = 1
      • as in implicit readPreference nearest

      Scope of changes

      Impact to Other Docs

      MVP (Work and Date)

      Resources (Scope or Design Docs, Invision, etc.)

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          documents

          New Feature - A new feature of the product, which has yet to be developed. SERVER-45439 Add support for per operation hedging via an explicit read preference

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

          Task - A task that needs to be done. DOCS-13506 Investigate changes in SERVER-46567: Update shell methods Mongo.setReadPref and cursor.readPref to support hedging

          • Major - P3 - Major loss of function.
          • Closed
          is related to

          Task - A task that needs to be done. DOCS-13429 Investigate changes in SERVER-46234: Remove the code for computing hedging delay and add maxTimeMSForHedgedReads serverParameter

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

          Task - A task that needs to be done. DOCS-13506 Investigate changes in SERVER-46567: Update shell methods Mongo.setReadPref and cursor.readPref to support hedging

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

          Activity

            People

              Unassigned Unassigned
              backlog-server-pm Backlog - Core Eng Program Management Team
              Jess Mokrzecki Jess Mokrzecki
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              Dates

                Created:
                Updated:
                Resolved:
                3 years, 11 weeks, 3 days ago