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  1. Core Server
  2. SERVER-47657

Add 'unique' and 'sparse' parameters to index signature

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Details

    • Improvement
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • None
    • 4.9.0
    • Index Maintenance
    • Fully Compatible
    • Query Execution 2021-02-22, Query Execution 2021-03-08
    • 40

    Description

      At present, an index's signature - that is, the combination of parameters which uniquely identify the index - is defined by its keypattern and collation. No index can be created if its signature is equivalent to an existing index. SERVER-25023 seeks to add the partialFilterExpression parameter to this list, such that multiple partial indexes could be built on the same fields so long as their filters are different.

      We should also add the unique and sparse parameters to the index signature. At present, it is not possible to build a sparse index on a particular key pattern if an existing non-sparse index is already present. Users who wish to move from a full index to a sparse index have little option but to drop the existing index before building the sparse version. A similar situation exists for users who wish to introduce a uniqueness constraint on a field which is already indexed. Workarounds do exist in these situations, but they are ugly and more labour-intensive than should be necessary.

      Attachments

        Issue Links

          is documented by

          Task - A task that needs to be done. DOCS-14277 Investigate changes in SERVER-47657: Add 'unique' and 'sparse' parameters to index signature

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

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-25023 no way to index the same fields with two different partial index filters

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

          Bug - A problem which impairs or prevents the functions of the product. SERVER-62636 setFeatureCompatibilityVersion 4.4 succeeds on 5.0 binVersion that has indexes with conflicting options

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

          Task - A task that needs to be done. SERVER-47766 Remove FCV guard on partialFilterExpression and wildcardProjection index signature comparison

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

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-47659 Add 'wildcardProjection' parameter to index signature

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

          Activity

            People

              yoonsoo.kim@mongodb.com Yoon Soo Kim
              bernard.gorman@mongodb.com Bernard Gorman
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              Dates

                Created:
                Updated:
                Resolved: