Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-35999

A $changeStream can trigger assertion on UUID check when the collection cache is stale

    • Type: Icon: Bug Bug
    • Resolution: Duplicate
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 3.6.5
    • Component/s: Aggregation Framework
    • None
    • ALL
    • Query 2018-07-30

      UUIDs were introduced in v3.6, however after upgrading from 3.4 it's possible that the collection state in-memory cache contains an entry for the collection (meaning it's sharded) but does not contain a UUID.  As such, this assertion will fail when a $changeStream compares the UUID from the oplog entry to the UUID in the collection state cache.

       Edit:

      Since change streams requires readConcern majority, the secondary will perform a shard version check but not necessarily refresh its cache. For change streams, mongos will not attach a shard version which means that the version check will always pass and no refresh is performed.

            Assignee:
            nicholas.zolnierz@mongodb.com Nicholas Zolnierz
            Reporter:
            nicholas.zolnierz@mongodb.com Nicholas Zolnierz
            Votes:
            1 Vote for this issue
            Watchers:
            6 Start watching this issue

              Created:
              Updated:
              Resolved: