Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-22572

readConcern majority doesn't consider replica-set changes

    • Type: Icon: Bug Bug
    • Resolution: Duplicate
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 3.2.1
    • Component/s: Replication
    • None
    • ALL
    • Repl 11 (03/11/16), Repl 12 (04/01/16)

      It would appear the only reason to throw away the set of snapshots used for readConcern is if the local node enters ROLLBACK:
      https://github.com/mongodb/mongo/blob/f8dadcefeef7e738d7063ae2df57b9c856b402da/src/mongo/db/repl/replication_coordinator_impl.cpp#L2518

      Replica-set reconfigs would seem to be another way to change the conditions needed to fulfill readConcern majority. For example, in a 5-member replica-set where 2 members are non-voting requires only 2 of the voting members to fulfill a majority readConcern. Reconfig to allow the other 2 members to vote means the set should now demand 3 members to achieve readConcern majority. However, the existing 'verified' snapshot on all members would continue to be used for this purpose despite it (not necessarily) fulfilling the current requirements.

            Assignee:
            scotthernandez Scott Hernandez (Inactive)
            Reporter:
            andrew.ryder@mongodb.com Andrew Ryder (Inactive)
            Votes:
            0 Vote for this issue
            Watchers:
            10 Start watching this issue

              Created:
              Updated:
              Resolved: