[
https://issues.apache.org/jira/browse/CASSANDRA-9200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14610599#comment-14610599
]
Jonathan Ellis commented on CASSANDRA-9200:
-------------------------------------------
bq. oracle and postgresql have the concept of a sequence "cache size" where
sequence ids are reserved per session as I am proposing here per coordinator
Oracle blog "Ask Tom" explains further:
bq. A sequence has one purpose: assign unique numbers to stuff. Nothing else.
There will be gaps, gaps are normal, expected, good, ok, fine. They will be
there, there is no avoiding them [even with cache size of 1]. This is not a
problem, it is expected, it is not "fixable" - a "rollback" for example will
generate a gap if some session selected a sequence. Do not assume they are gap
free and all is well in the world.
https://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:369390500346406705
> 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
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
