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https://issues.apache.org/jira/browse/CASSANDRA-3881?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13283289#comment-13283289
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Sam Overton commented on CASSANDRA-3881:
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The original approach was not quite there. The snitch was tracking the topology
of nodes in NORMAL state for the benefit of NTS.calculateNaturalEndpoints, but
calculateNaturalEndpoints is called with modified TokenMetadata (eg, with
leaving nodes removed, or a bootstrapped node added or some other modification)
to calculate ranges for some future state of the ring, not the current state as
tracked by the snitch.
The correct solution is to have TokenMetadata track the topology of the nodes
which it considers to be part of the ring, so that when a tokenMetadata is
cloned and modified it also updates its view of the topology. This is also much
simpler and cleaner.
Patches above are updated.
> reduce computational complexity of processing topology changes
> --------------------------------------------------------------
>
> Key: CASSANDRA-3881
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3881
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Peter Schuller
> Assignee: Sam Overton
> Labels: vnodes
>
> This constitutes follow-up work from CASSANDRA-3831 where a partial
> improvement was committed, but the fundamental issue was not fixed. The
> maximum "practical" cluster size was significantly improved, but further work
> is expected to be necessary as cluster sizes grow.
> _Edit0: Appended patch information._
> h3. Patches
> ||Compare||Raw diff||Description||
> |[00_snitch_topology|https://github.com/acunu/cassandra/compare/refs/top-bases/p/3881/00_snitch_topology...p/3881/00_snitch_topology]|[00_snitch_topology.patch|https://github.com/acunu/cassandra/compare/refs/top-bases/p/3881/00_snitch_topology...p/3881/00_snitch_topology.diff]|Adds
> some functionality to AbstractEndpointSnitch to track which endpoints and
> racks exist in a DC.|
> |[01_calc_natural_endpoints|https://github.com/acunu/cassandra/compare/refs/top-bases/p/3881/01_calc_natural_endpoints...p/3881/01_calc_natural_endpoints]|[01_calc_natural_endpoints.patch|https://github.com/acunu/cassandra/compare/refs/top-bases/p/3881/01_calc_natural_endpoints...p/3881/01_calc_natural_endpoints.diff]|Rewritten
> O(logN) implementation of calculateNaturalEndpoints using the topology
> information from the snitch.|
> ----
> _Note: These are branches managed with TopGit. If you are applying the patch
> output manually, you will either need to filter the TopGit metadata files
> (i.e. {{wget -O - <url> | filterdiff -x*.topdeps -x*.topmsg | patch -p1}}),
> or remove them afterward ({{rm .topmsg .topdeps}})._
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