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https://issues.apache.org/jira/browse/CASSANDRA-15385?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16964009#comment-16964009
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Aleksey Yeschenko commented on CASSANDRA-15385:
-----------------------------------------------
CASSANDRA-7544 allowed storage port to be configurable per node, and among its
changes introduced several new columns to some of the distributed system tables:
1. {{coordinator_port}} and {{participants_v2}} to
{{system_distributed.repair_history}}
2. {{coordinator_port}} to {{system_traces.sessions}}
3. {{source_port}} to {{system_traces.events}}
(1) is not a huge deal, since we don't support repair in mixed mode clusters;
(2) and (3), however, are. And while CASSANDRA-14841 modifies tracing logic to
not write those new added columns while still in mixed mode, this is still a
problem for reads - which in case of tracing will be issued automatically by
the drivers.
CASSANDRA-14897 gives advice to add some of these columns manually (though not
tracing) while still on 3.x, but there is a reason why such alters are
explicitly forbidden and require a workaround: distributed pseudo-system tables
are evolved programmatically, by bumping internal generation timestamp. Mixing
manual alters and real-world timestamps and those surrogate timestamps simply
prevents us from deterministically evolving those schemas in future versions.
The patches to be linked pre-add the columns on 3.0/3.11 side automatically,
preserving the correct timestamps, so that tracing can go on uninhibited,
without crashing the internode connections and losing the enqueued messages in
the process.
> Ensure that tracing doesn't break connections in 3.x/4.0 mixed mode by default
> ------------------------------------------------------------------------------
>
> Key: CASSANDRA-15385
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15385
> Project: Cassandra
> Issue Type: Bug
> Components: Observability/Tracing
> Reporter: Aleksey Yeschenko
> Assignee: Aleksey Yeschenko
> Priority: Normal
> Fix For: 3.0.x, 3.11.x
>
>
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