[CASSANDRA-12216] TTL Reading And Writing is Asymmetric

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 3.10
• Component/s: Legacy/CQL
• Assignee: Russell Spitzer Assign to me
• Reporter: Russell Spitzer

Authors

Russell Spitzer

Reviewers

Benjamin Lerer

• Created: 15/Jul/16 20:16
• Updated: 16/Apr/19 09:30
• Resolved: 16/Aug/16 14:40

Description

There is an inherent asymmetry in the way TTL's are read and Written.

An `TTL` of 0 when written becomes a `null` in C*
When read, this `TTL` becomes a `null`
The `null` cannot be written back to C* as `TTL`

This means that end users attempting to copy tables with TTL have to do manual mapping of the null TTL values to 0 to avoid NPE. This is a bit onerous when C* seems to have an internal logic that 0 == NULL. I don't think C* should return values which are not directly insertable back to C*.

Even with the advent CASSANDRA-7304 this still remains a problem that the User needs to be aware of and take care of.

The following prepared statement

INSERT INTO test.table2 (k,v) (?,?) USING TTL: ? 

Will throw NPEs unless we specifically check that the value to be bound to TTL is not null.

I think we should discuss whether `null` should be treated as 0 in TTL for prepared statements.