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https://issues.apache.org/jira/browse/CASSANDRA-5001?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-5001:
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Reviewer: [email protected]
> Generated time-based UUID don't conform to the spec
> ---------------------------------------------------
>
> Key: CASSANDRA-5001
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5001
> Project: Cassandra
> Issue Type: Bug
> Reporter: Sylvain Lebresne
> Assignee: Sylvain Lebresne
> Priority: Minor
> Fix For: 1.2.0
>
> Attachments: 5001.txt
>
>
> When UUIDGen layout the clock sequence and and node part of version 1 UUID,
> it does so with
> {noformat}
> private long getClockSeqAndNode(InetAddress addr)
> {
> long lsb = 0;
> lsb |= (clock & 0x3f00000000000000L) >>> 56; // was 58?
> lsb |= 0x0000000000000080;
> lsb |= (clock & 0x00ff000000000000L) >>> 48;
> lsb |= makeNode(addr);
> return lsb;
> }
> {noformat}
> This is not correct however, as this layout the clock seq (and variant) on
> the right-most part of the lsb while it should be on the left-most one.
> At a minimum, the generated UUID don't fully respect the spec since the
> variant is not set correctly. But it also means that the clock seq bits end
> up being all 0's (as can be trivially seen in the string representation of
> the generated UUIDs).
> Note that none of those is a huge huge deal as there is still largely enough
> random bytes to ensure that two different nodes won't end up with the same
> lsb. And having the variant wrong has probably no practical implementation.
> There is no reason not to fix those though.
> One other small details is that the getAdjustedTimestamp as a sign error so
> that it returns completely broken timestamps. That being said the method is
> currently unused so that's not a big deal. I'm attaching a fix for that part
> too because that method might be useful someday but I won't shed a tear if we
> prefer just removing it.
> I'm marking this for 1.2 because I'm not sure it's worth bothering with 1.1.
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