[jira] [Commented] (CASSANDRA-7304) Ability to distinguish between NULL and UNSET values in Prepared Statements

["Oded Peer (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-7304?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14048588#comment-14048588 ] 

Oded Peer commented on CASSANDRA-7304:
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Aren't you concerned about backward compatibility?
If clients assume unset bind variables in prepared statements deletes the column value then ignoring unset bind variables breaks that assumption.

That said, assuming you differentiate between 'null' and 'unset' values using the size of the value, would it be acceptable to mark unset values with a new class (return "UnsetByteBuffer") and using instanceof to ignore the bind variable?


> Ability to distinguish between NULL and UNSET values in Prepared Statements
> ---------------------------------------------------------------------------
>
>                 Key: CASSANDRA-7304
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7304
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Drew Kutcharian
>              Labels: cql
>         Attachments: 7304.patch
>
>
> Currently Cassandra inserts tombstones when a value of a column is bound to NULL in a prepared statement. At higher insert rates managing all these tombstones becomes an unnecessary overhead. This limits the usefulness of the prepared statements since developers have to either create multiple prepared statements (each with a different combination of column names, which at times is just unfeasible because of the sheer number of possible combinations) or fall back to using regular (non-prepared) statements.
> This JIRA is here to explore the possibility of either:
> A. Have a flag on prepared statements that once set, tells Cassandra to ignore null columns
> or
> B. Have an "UNSET" value which makes Cassandra skip the null columns and not tombstone them
> Basically, in the context of a prepared statement, a null value means delete, but we don’t have anything that means "ignore" (besides creating a new prepared statement without the ignored column).
> Please refer to the original conversation on DataStax Java Driver mailing list for more background:
> https://groups.google.com/a/lists.datastax.com/d/topic/java-driver-user/cHE3OOSIXBU/discussion



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