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From "Aleksey Yeschenko (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-9200) Sequences
Date Wed, 01 Jul 2015 17:08:07 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-9200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14610652#comment-14610652
] 

Aleksey Yeschenko commented on CASSANDRA-9200:
----------------------------------------------

bq. Not sure what your counterproposal is. "Projecting" tokens to longs is going to result
in duplicate longs which is not acceptable. (And as tupshin notes, some users need a 32bit
solution as well.)

It would work for 64 bytes. For 32 bytes some math would be required.

After some offline conversations - I'm fine with partition-scoped sequences (assuming someone
comes up with a decent plan for them).

bq. This is the key, if we don't deliver something good enough users will be forced to roll
something worse themselves. 

This is true for many features <X>. It's expected that Cassandra will not provide you
with all the functionality you can possibly need. Having people roll their own is fine sometimes,
if the alternative is putting everything in C*. Especially features that are bad architectural
fit with Cassandra model.

> Sequences
> ---------
>
>                 Key: CASSANDRA-9200
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9200
>             Project: Cassandra
>          Issue Type: New Feature
>            Reporter: Jonathan Ellis
>            Assignee: Robert Stupp
>             Fix For: 3.x
>
>
> UUIDs are usually the right choice for surrogate keys, but sometimes application constraints
dictate an increasing numeric value.
> We could do this by using LWT to reserve "blocks" of the sequence for each member of
the cluster, which would eliminate paxos contention at the cost of not being strictly increasing.
> PostgreSQL syntax: http://www.postgresql.org/docs/9.4/static/sql-createsequence.html



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