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https://issues.apache.org/jira/browse/CASSANDRA-6477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13955260#comment-13955260
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Jonathan Ellis edited comment on CASSANDRA-6477 at 3/31/14 4:49 PM:
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Sylvain had a different idea:
Instead of just writing a {{24, user1}} tombstone, write a tombstone that
indicates what the value changed to: {{24, user1 -> 25}} for one thread, and
{{24, user1 -> 26}} for the other.
When the tombstones are merged for compaction or read, you can say "wait 2
people tried to erase that, one with 25 the other with 26, let's check which
was has a higher timestamp and delete any obsolete entries."
was (Author: jbellis):
Sylvain had a different idea:
Instead of just writing a {{24, user1}} tombstone, write a tombstone that
indicates what the value changed to: {{24, user1 -> 25}} for one thread, and
{{24, user1 -> 26}} for the other.
When the tombstones is merged for compaction or read, you can say "wait 2
people tried to erase that, one with 25 the other with 26, let's check which
was has a higher timestamp and delete any obsolete entries."
> Partitioned 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
> 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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