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https://issues.apache.org/jira/browse/CASSANDRA-11529?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15231202#comment-15231202
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Russell Bradberry commented on CASSANDRA-11529:
-----------------------------------------------
This is a critical issue for us as our cluster is in a mixed-version state
where we have coordinator-only nodes running an older version to compensate for
this issue. The impact on a 50 node (8 cores, 256 vnodes) cluster with a few
thousand batch inserts per second sends the average load to above 120.
> Checking if an unlogged batch is local is inefficient
> -----------------------------------------------------
>
> Key: CASSANDRA-11529
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11529
> Project: Cassandra
> Issue Type: Bug
> Components: Coordination
> Reporter: Paulo Motta
>
> Based on CASSANDRA-11363 report I noticed that on CASSANDRA-9303 we
> introduced the following check to avoid printing a {{WARN}} in case an
> unlogged batch statement is local:
> {noformat}
> for (IMutation im : mutations)
> {
> keySet.add(im.key());
> for (ColumnFamily cf : im.getColumnFamilies())
> ksCfPairs.add(String.format("%s.%s",
> cf.metadata().ksName, cf.metadata().cfName));
> +
> + if (localMutationsOnly)
> + localMutationsOnly &= isMutationLocal(localTokensByKs,
> im);
> }
>
> + // CASSANDRA-9303: If we only have local mutations we do not warn
> + if (localMutationsOnly)
> + return;
> +
> NoSpamLogger.log(logger, NoSpamLogger.Level.WARN, 1,
> TimeUnit.MINUTES, unloggedBatchWarning,
> keySet.size(), keySet.size() == 1 ? "" : "s",
> ksCfPairs.size() == 1 ? "" : "s", ksCfPairs);
> {noformat}
> The {{isMutationLocal}} check uses
> {{StorageService.instance.getLocalRanges(mutation.getKeyspaceName())}}, which
> underneaths uses {{AbstractReplication.getAddressRanges}} to calculate local
> ranges.
> Recalculating this at every unlogged batch can be pretty inefficient, so we
> should at the very least cache it every time the ring changes.
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