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https://issues.apache.org/jira/browse/CASSANDRA-4284?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13411844#comment-13411844
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paul cannon commented on CASSANDRA-4284:
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bq. But if we don't do anything here, I would be of the opinion of making cqlsh
stop interpreting timeuuid as date by default because I'm afraid it will
confuse more people than it will help.
I'd much rather have the % syntax addition than to do this. It seems like
people using timeuuid will "usually" want to see the date value associated with
their timeuuids, not the actual uuid value. They can still get the latter with
an ASSUME, but I think that would be the exception, not the rule. We might just
need to make that particular use of ASSUME more easily found (maybe put it in
the CQL3 docs along with the description of timeuuid).
What if we (a) filled in random bits for the MAC address area of the uuids, and
(b) extended the recognized timestamp syntax to allow specifying fractional
seconds? We have 7 extra digits of precision that we could be allowing users to
employ. It's lots more obvious what the extra digits mean when printed, and
people can understand easily how their values will sort with respect to other
timeuuids. If a user inserts multiple timestamps with the exact same value
(down to the 100-ns precision), then they will end up being sorted randomly
with respect to each other, but the user should have no expectations about
their ordering, so that's ok. Of course if the user wants to specify the entire
value of the uuid, she can use the uuid syntax.
> Improve timeuuid <-> date relationship
> --------------------------------------
>
> Key: CASSANDRA-4284
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4284
> Project: Cassandra
> Issue Type: Improvement
> Components: API
> Affects Versions: 1.1.0
> Reporter: Sylvain Lebresne
> Assignee: Sylvain Lebresne
> Priority: Minor
> Labels: cql3
> Fix For: 1.2
>
>
> We added timeuuid to CQL3, whose purpose is to provide a collision-free
> timestamp basically and as a convenience, such timeuuid can be inputed as as
> date.
> However, two things seems non-optimal to me:
> * When one insert a timeuuid using a date format, we always pick *the* UUID
> corresponding to this date with every other part of the UUID to 0. This kind
> of defeat the purpose of collision-free timestamp and thus greatly limit the
> usefulness of the date syntax.
> * When cqlsh print timeuuid, it print them as date. But as thus, there is
> some information lost which can be problematic (you can't update a specific
> column based on that return). In a way, this is a cqlsh limitation, since
> cassandra return the UUID bytes. Yet, it also emphasis somehow that from the
> point of using them, timeuuid are more UUID than really time.
> For the first point, it would make more sense that when inserting a date, we
> actually pick a uuid with the corresponding timestamp *but* with the rest of
> the UUID being random. It's not completely that simple because we don't want
> that randomness when the date are used in a select query, but that's roughtly
> the same problem than CASSANDRA-4283 (and we can thus use the same solution).
> The second point gives an idea. We could extends the date syntax to allow it
> to represent uniquely a type 1 UUID. Typically, we could allow something
> like: '2012-06-06 12:03:00+0000 %a2fc07', where the part after the '%'
> character would be hexadecimal for the non-timestamp part of the UUID.
> Understanding this syntax could allow to work with timeuuid uniquely with
> meaningful date string which I think would be neat. But maybe that's a crazy
> idea, opinions?
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