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From "Tyler Hobbs (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7423) Allow updating individual subfields of UDT
Date Wed, 02 Mar 2016 17:33:18 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15176045#comment-15176045
] 

Tyler Hobbs commented on CASSANDRA-7423:
----------------------------------------

That makes sense -- I'm not sure why I didn't think of that yesterday.  I've force-pushed
an update to the branch that checks for non-frozen collections nested within non-frozen UDTs
when creating a table.

> Allow updating individual subfields of UDT
> ------------------------------------------
>
>                 Key: CASSANDRA-7423
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7423
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: CQL
>            Reporter: Tupshin Harper
>            Assignee: Tyler Hobbs
>              Labels: client-impacting, cql, docs-impacting
>             Fix For: 3.x
>
>
> Since user defined types were implemented in CASSANDRA-5590 as blobs (you have to rewrite
the entire type in order to make any modifications), they can't be safely used without LWT
for any operation that wants to modify a subset of the UDT's fields by any client process
that is not authoritative for the entire blob. 
> When trying to use UDTs to model complex records (particularly with nesting), this is
not an exceptional circumstance, this is the totally expected normal situation. 
> The use of UDTs for anything non-trivial is harmful to either performance or consistency
or both.
> edit: to clarify, i believe that most potential uses of UDTs should be considered anti-patterns
until/unless we have field-level r/w access to individual elements of the UDT, with individual
timestamps and standard LWW semantics



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