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  1. Core Server
  2. SERVER-54874

Ensure reading of consistent config.collections and config.chunks when refreshing the CatalogCache

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    • Fully Compatible
    • Sharding 2021-03-22
    • 126

    Description

      Currently, when the ConfigServerCatalogCache refreshes, it first issues a majority read on config.collections and after that it issues a second majority read on config.chunks Because of this, the collection metadata we read from config.collections may not be consistent with the chunks (and thus collection version) we read from config.chunks.

      To address this we need to ensure that we read config.collections and config.chunks 'as a package'. To do so, we can use an aggregation pipeline on config.collections that has a $lookUp stage from config.chunks, and attach a snapshot read concern.

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          causes

          Bug - A problem which impairs or prevents the functions of the product. SERVER-56190 Fix wrong nss in ExpressionContext for CatalogCache refresh aggregation

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

          Task - A task that needs to be done. SERVER-59803 Set maxTimeMs for catalog cache refresh aggregation

          • Major - P3 - Major loss of function.
          • Closed
          is depended on by

          Bug - A problem which impairs or prevents the functions of the product. SERVER-53539 TypeCollectionReshardingFields are incorrect following a shard version refresh

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

          Bug - A problem which impairs or prevents the functions of the product. SERVER-56302 Catalog cache refresh can fail with SnapshotTooOld after query yields

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

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              jordi.serra-torrens@mongodb.com Jordi Serra Torrens
              jordi.serra-torrens@mongodb.com Jordi Serra Torrens
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                Updated:
                Resolved: