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  1. Core Server
  2. SERVER-2130

Ability to use Limit() with Distinct()

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Details

    • New Feature
    • Status: Backlog
    • Major - P3
    • Resolution: Unresolved
    • None
    • None
    • Querying
    • all
    • Query Optimization

    Description

      Ability to use Limit() with Distinct()... or any of the cursor methods for the matter (sort, count, skip, etc. although limit has the biggest impact).

      Apparently there is no simple way to currently perform the following SQL query:

      SELECT DISTINCT(myField) FROM myTable WHERE x = y LIMIT(20)

      The current Distinct() implementation only allows for bringing back ALL distinct values in the collection or matching a query, but there is no way to limit these results. This would be very convenient and there are many use cases.

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          related to

          New Feature - A new feature of the product, which has yet to be developed. SERVER-25184 Add a $distinct aggregation stage

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

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-4507 aggregation: optimize $group to take advantage of sorted sequences

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

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-27915 Make $group with $addToSet accumulator use DISTINCT_SCAN when applicable

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

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-9507 Optimize $sort+$group+$first pipeline to avoid full index scan

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

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              Dates

                Created:
                Updated: