[
https://issues.apache.org/jira/browse/CASSANDRA-9198?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14501694#comment-14501694
]
Jeff Jirsa commented on CASSANDRA-9198:
---------------------------------------
We brushed on this in CASSANDRA-9077
The fact that the list can become null just by removing elements from it seems
non-intuitive to me (not to say it's wrong, just that I don't think most
developers would expect it) - it seems like it should become empty, not null.
I would expect `DELETE FROM foo WHERE k=1` to result in a null list, but simply
removing an element from a list should result in an empty list.
> Deleting from an empty list produces an error
> ---------------------------------------------
>
> Key: CASSANDRA-9198
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9198
> Project: Cassandra
> Issue Type: Bug
> Components: API
> Reporter: Olivier Michallat
> Assignee: Benjamin Lerer
> Priority: Minor
> Fix For: 3.0
>
>
> While deleting an element from a list that does not contain it is a no-op,
> deleting it from an empty list causes an error.
> This edge case is a bit inconsistent, because it makes list deletion non
> idempotent:
> {code}
> cqlsh:test> create table foo (k int primary key, v list<int>);
> cqlsh:test> insert into foo(k,v) values (1, [1,2]);
> cqlsh:test> update foo set v = v - [1] where k = 1;
> cqlsh:test> update foo set v = v - [1] where k = 1;
> cqlsh:test> update foo set v = v - [2] where k = 1;
> cqlsh:test> update foo set v = v - [2] where k = 1;
> InvalidRequest: code=2200 [Invalid query] message="Attempted to delete an
> element from a list which is null"
> {code}
> With speculative retries coming to the drivers, idempotency becomes more
> important because it determines which query we might retry or not. So it
> would be better if deleting from an empty list succeeded.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
