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https://issues.apache.org/jira/browse/CASSANDRA-6477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14497174#comment-14497174
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Jonathan Ellis edited comment on CASSANDRA-6477 at 4/16/15 2:54 AM:
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bq. we would need to have a single replica that we push all index updates
through
You're right, that doesn't work.
bq. it would very difficult to determine whether a grouping of updates
indicates simultaneous updates or just a series of updates that happened to use
the same values
I don't think that makes it not work. Each of those values is a separate
partition. I think we get the right answer if we just take the
highest-timestamped value for each partition and delete any "ghost" entries
that may have been missed.
was (Author: jbellis):
bq. we would need to have a single replica that we push all index updates
through
You're right, that doesn't work.
bq. it would very difficult to determine whether a grouping of updates
indicates simultaneous updates or just a series of updates that happened to use
the same values
I don't think that makes it not work. Each of those values is a separate
partition. I think we get the right answer if we just take the highest value
for each partition and delete any "ghost" entries that may have been missed.
> Global indexes
> --------------
>
> Key: CASSANDRA-6477
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6477
> Project: Cassandra
> Issue Type: New Feature
> Components: API, Core
> Reporter: Jonathan Ellis
> Assignee: Carl Yeksigian
> Labels: cql
> Fix For: 3.0
>
>
> Local indexes are suitable for low-cardinality data, where spreading the
> index across the cluster is a Good Thing. However, for high-cardinality
> data, local indexes require querying most nodes in the cluster even if only a
> handful of rows is returned.
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