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https://issues.apache.org/jira/browse/CASSANDRA-9198?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14503088#comment-14503088
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Sylvain Lebresne commented on CASSANDRA-9198:
---------------------------------------------
bq. last time we discussed that subject, we agreed that as we complain on
invalid index for lists, not complaining when trying to delete from an empty
list was not really consistent.
Yes, but I hadn't though of the idempotency issue at the time, and I do think
we should make thing idempotent as much as possible, so +1 for not complaining
in that case. And since this case was buggy until CASSANDRA_9077, I suggest we
fix that before 2.1.5 is released.
> 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.
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