[jira] [Commented] (CASSANDRA-12060) Different failure format for failed LWT between 2.x and 3.x

["Sylvain Lebresne (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-12060?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15346028#comment-15346028 ] 

Sylvain Lebresne commented on CASSANDRA-12060:
----------------------------------------------

In a way, that it behaves the same way in 3.x whether or not the partition itself exists or not is consistent with not making a distinction for static column {{ == null }} conditions between having the partition exists or not (CASSANDRA-9842). That said, I'm having second though about CASSANDRA-9842. I know I said offline that trying to make a difference between the 2 cases was probably annoying, but I think I was tired when I said that because I said otherwise earlier in [this comment|https://issues.apache.org/jira/browse/CASSANDRA-9842?focusedCommentId=15066724&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15066724]. Long story short, from a pure consistency of the language standpoint, I wonder if the best course of action wouldn't be to 1) re-open CASSANDRA-9842 to see if we can make it behave so that {{s == null}} only apply if the partition exists (and s is {{null}} obviously) and 2) fix this issue so that 3.x behaves as 2.x.

Otherwise, if we think keeping CASSANDRA-9842 as is is the right thing to do, then I think it follows that the 3.x behavior is kind of correct, and we'll have to document it as a change of behavior.

> Different failure format for failed LWT between 2.x and 3.x
> -----------------------------------------------------------
>
>                 Key: CASSANDRA-12060
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-12060
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Alex Petrov
>
> When executing following CQL commands: 
> {code}
> CREATE KEYSPACE test WITH replication = {'class': 'NetworkTopologyStrategy', 'datacenter1': '1' };
> USE test;
> CREATE TABLE testtable (a int, b int, s1 int static, s2 int static, v int, PRIMARY KEY (a, b));
> INSERT INTO testtable (a,b,s1,s2,v) VALUES (2,2,2,null,2);
> DELETE s1 FROM testtable WHERE a = 2 IF s2 IN (10,20,30);
> {code}
> The output is different between {{2.x}} and {{3.x}}:
> 2.x:
> {code}
> cqlsh:test> DELETE s1 FROM testtable WHERE a = 2 IF s2 = 5;
>  [applied] | s2
> -----------+------
>      False | null
> {code}
> 3.x:
> {code}
> cqlsh:test> DELETE s1 FROM testtable WHERE a = 2 IF s2 = 5;
>  [applied]
> -----------
>      False
> {code}
> {{2.x}} would although return same result if executed on a partition that does not exist at all:
> {code}
> cqlsh:test> DELETE s1 FROM testtable WHERE a = 5 IF s2 = 5;
>  [applied]
> -----------
>      False
> {code}
> It _might_ be related to static column LWTs, as I could not reproduce same behaviour with non-static column LWTs. The most recent change was [CASSANDRA-10532], which enabled LWT operations on static columns with partition keys only. Another possible relation is [CASSANDRA-9842], which removed distinction between {{null}} column and non-existing row.



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