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  1. Cassandra
  2. CASSANDRA-13441

Schema version changes for each upgraded node in a rolling upgrade, causing migration storms

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    • Severity:
      Normal

      Description

      In versions < 3.0, during a rolling upgrade (say 2.0 -> 2.1), the first node to upgrade to 2.1 would add the new tables, setting the new 2.1 version ID, and subsequently upgraded hosts would settle on that version.

      When a 3.0 node upgrades and writes its own new-in-3.0 system tables, it'll write the same tables that exist in the schema with brand new timestamps. As written, this will cause all nodes in the cluster to change schema (to the version with the newest timestamp). On a sufficiently large cluster with a non-trivial schema, this could cause (literally) millions of migration tasks to needlessly bounce across the cluster.

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              • Assignee:
                jjirsa Jeff Jirsa
                Reporter:
                jjirsa Jeff Jirsa
                Authors:
                Jeff Jirsa
                Reviewers:
                Aleksey Yeschenko
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                  Updated:
                  Resolved: