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Sylvain Lebresne commented on CASSANDRA-4843:
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bq. why are we changing the default?
The reason is that md5 is a bit cpu intensive and in some 2ndary index requests
(that does a token computation for each key on disk it scans for internal
reason that can't be changed easily) this was a bottleneck. The new default is
the Murmur3Partitioner that is much cheaper to compute. Besides, for every
query we do compute a bunch of token and vnodes will probably not reduce that,
so it's a generic improvement.
That being said, I fully agree that the current upgrade experience is pretty
harsh (even the NEWS file don't clearly explain the action to take to avoid
this error). And since we save the partitonner and don't start if the user
change it in the yaml, maybe it's time to change the behavior so that if a
partitioner is saved in the system table, we use that (and log a warning if it
differs from the yaml configured one).
> When upgrading from 1.1.6 to 1.20 change in partitioner causes nodes not to
> start
> ---------------------------------------------------------------------------------
>
> Key: CASSANDRA-4843
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4843
> Project: Cassandra
> Issue Type: Bug
> Reporter: Edward Capriolo
> Fix For: 1.2.0 beta 2
>
>
> ERROR 10:17:20,341 Cannot open
> /home/edward/cassandra/data/system/schema_keyspaces/system-schema_keyspaces-hf-1
> because partitioner does not match
> org.apache.cassandra.dht.RandomPartitioner !=
> org.apache.cassandra.dht.Murmur3Partitioner
> This is because 1.2 has a new default partitioner, why are we changing the
> default? Is this wise? The current partitioner has been rock solid for years.
> Should the previously known partition be stored in the schema like the
> previously know seed nodes, and schema?
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