[CASSANDRA-5292] CQL3 shouldn't lowercase DC names for NTS

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 1.2.3
• Severity: Normal
• Assignee: Sylvain Lebresne
• Reporter: Sylvain Lebresne

Authors

Sylvain Lebresne

Reviewers

Jonathan Ellis

• Created: 26/Feb/13 17:16
• Updated: 16/Apr/19 09:32
• Resolved: 27/Feb/13 14:46

Description

In CREATE and ALTER statements, when a property map is given (replication, compaction and compression options), CQL3 lowercase the map keys to provide case insensitivity. The goal is to allow things like:

  replication = { 'Class' : 'SimpleStrategy', 'Replication_factor' : '1' }

However, this messes up with NTS, as it ends up lower-casing the datacenter names. As a consequence,

  replication = { 'class' : 'NetworkTopologyStrategy', 'DC1' : '1' }

will currently create a DC that is really called 'dc1', which is a problem because DC names are interpreted case sensitively otherwise (at least in PropertyFileSnitch).

That's the problem. Now I'm kind of hesitant on what is the right fix. I see the following possibilities:

1. Remove the CQL3 lower-casing completely. I'll admit that providing case insensitivy for property map keys may not have been such a good idea in the first place. After all, those map keys are string literal, which rather suggest case sensitivity. However, making that change would be a break strictly speaking.
2. Make DC name case insensitive. As much as I think DC names ought to be case insensitive, I'm not sure that's very doable in practice because that would imply storing DC names lower-cased internally, but DC names are exchanged over gossip and whatnot, so that would probably break all hell loose.
3. Keep CQL3 case insensitivity for property map keys in general but special case internally for NTS. The problems I see with that is that 1) this will be ugly and 2) if we special case too much, we might break potential custom strategies inspired by NTS. I also had the idea of changing strategy options internally from Map<String, String> to some custom object that would be essentially a case insensitive string map (general case), but that would also hold the original case of keys so NTS (and any other likely-minded strategy) can do its stuff. This happens to not be a small patch however (I'm attaching the patch for reference because I wrote it, but I'm seriously wondering if it's not too overkill).