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Benjamin Lerer commented on CASSANDRA-17425:
--------------------------------------------
{quote}
It is different from CASSANDRA-8877, which is to retrieve the timestamp of one
cell from a multi-cell type and end-user cannot tell if the retrieved timestamp
is the latest.
{quote}
There were 2 parts to CASSANDRA-8877 as [~slebresne] pointed out. One was about
allowing to select an element of the collection which has been implemented as
part of CASSANDRA-7396 (not for list through). The other part was about what we
should return when we use {{writetime}} or {{ttl}} on a multi-cell collection.
Should we return a list of timestamps/ttls? In my opinion that is probably what
we should do (I believe that [~adelapena] has a patch for that. It might need
to be reworked a bit.)
Adding a {{maxtimestamp}} and a {{minttl}} function will probably be much
easier at that point as it should be possible to implement it by only modifying
{{WritetimeOrTTLSelector}}.
{quote}I can see the concerns when I was working on the patch. It feels like
the selector framework needs some refactor, which I did not do in this
patch.{quote}
I woud prefer to wait a bit for it because I have some significant changes
coming in this area for CASSANDRA-11871.
Nevertheless, if you have some ideas I am really interested to hear them.
> Add new CQL function maxWritetime
> ---------------------------------
>
> Key: CASSANDRA-17425
> URL: https://issues.apache.org/jira/browse/CASSANDRA-17425
> Project: Cassandra
> Issue Type: Improvement
> Components: CQL/Syntax
> Reporter: Yifan Cai
> Assignee: Yifan Cai
> Priority: Normal
>
> The function "writetime" does not support multi-cell types, e.g. collections
> and UDT. It would be useful to enable querying the latest modified timestamp
> of a column value.
> I'd like to propose to add a new function named "maxWritetime", which returns
> the largest timestamp amongst the cells. When being applied to the single
> cell types, it returns the same result as "writetime".
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