1. CQL, ‘THEN AND NOW’ Cassandra London Feb, 20th 2012 Courtney Robinson email@example.com @zcourts http://crlog.info github.com/zcourts
2. IN THE BEGINNING ...horrible thrift code here
3. AND THEN THERE WAS... ...better looking hector code here
4. NOT QUITE ...slightly better (my hector wrapper) Still not excellent, but better (I think) Remember, not all languages have clients as good as hector. Usability varied* vastly between the supported languages So much so I chose Play! Framework over PHP for a small admin front end.
5. YAY! CQL TO SAVE THE DAY! ...because not everyone has an Ops team to torture. Upgrading wasn’t such a pain, little or no code breaking CQL offered stability (ish)...
6. BRIEF INTRO – WHAT IS IT? Simple, structured query language for Cassandra Very much SQL (except where it can’t be) Alternative to the Thrift RPC API. Available since Cassandra version 0.8.0 In keeping with Eric Evan’s attempts, just pronounce it ‘siːkwəl’ Isn’t much* to say about CQL, its does what it says on the tin
7. CONTROVERSY, POLITICS AND OUT RIGHT BI***ING Always been an outspoken (some more than others) few against it Never been much in the way of facts to backup their claims such as: SQL like syntax is a very idiomatic RDMS thing. Parsing a string will be slow, just because its parsing a string and for no other reason The aforementioned will make Cassandra ‘as vulnerable’ to injection ...etc (all speculation mind you)
8. SO WHAT, CAN I USE THIS THING? CQL is very much production ready. If anyone tells you otherwise, ask them to prove its not before you decide. My tiny 5 Node cluster is nothing to boast about, but it handles a good 150+ GB of data a day Every* query is done with CQL Except on a single CF which uses super columns. CQL does not and most likely will not ever support super columns. Compound column (CASSANDRA-2474 monster ticket) resolved (ish).
9. CQL V1.0.0 - DEBUT KEYWORDS USE SELECT That’s right! UPDATE DELETE No INSERT...? TRUNCATE DROP BATCH SPECIAL STATEMENTS CREATE KEYSPACE CREATE COLUMNFAMILY CREATE INDEX 10 total
10. TIME TELLS NO LIES, CQL V2 ALTER COLUMNFAMILY BATCH Create table is nothing more than an alias to create CREATE INDEX columnfamily CREATE KEYSPACE CREATE COLUMNFAMILY CREATE TABLE (CASSANDRA-2743) DELETE Rational: ‘create an DROP COLUMNFAMILY alias to be friendlier DROP INDEX to existing tools’ DROP KEYSPACE INSERT SELECT TRUNCATE 15 total UPDATE USE
11. CQL V3, AKA CASSANDRA-3761 About 13 sub-tickets Most unresolved It’d be unwise to list features Any of these could be dropped/altered before V3 is finalized (C* V1.1.1 is the roadmap release for V3) Backwards incompatibility (hence major version jump) Not the little project it used to be, would take all night to cover each feature with enough details
12. TERMINOLOGY WAR... CQL’s changing fast (maybe too fast?) Terminology looks to be changing Creating over lap in some places May become, or already is confusing Not sure those in charge are seeing it At a stage where its probably as confusing as other, more complicated C* features Progress is great, but so is usability & simplicity...
13. COURTNEY ROBINSON @ZCOURTS Thank you for listening. Questions? Links: https://github.com/apache/cassandra/blob/trunk/doc/cql/CQL.textile http://crlog.info/2011/09/17/cassandra-query-language-cql-v2-0-reference/ https://issues.apache.org/jira/browse/CASSANDRA-2743