Cassandra = No Joins. Your model is 100% relational. You need to rethink it for Cassandra. I would advice you take a look at these slides. They dig deep into how to model data for cassandra. Also here is a webinar covering the topic. But stop thinking foreign keys and joining tables, because if you … Read more
select * from update_audit where scopeid=35 and formid=78005 and record_link_id=9897; How the above query will work internally in cassandra? Essentially, all data for partition scopeid=35 and formid=78005 will be returned, and then filtered by the record_link_id index. It will look for the record_link_id entry for 9897, and attempt to match-up entries that match the rows … Read more
In an effort to answer your questions, I did a little digging on this one. Does Cassandra capture microseconds with timestamp data type? Microseconds no, milliseconds yes. If I create your table, insert a row, and try to query it by the truncated time, it doesn’t work: aploetz@cqlsh:stackoverflow> INSERT INTO data (datetime, id, type, data) … Read more
The timeout is because Cassandra is taking longer than the timeout (default is 10 seconds) to return the data. For your query, Cassandra will attempt to fetch the entire dataset before returning. For more than a few records this can easily take longer than the timeout. For queries that are producing lots of data you … Read more
With Cassandra you solve these kinds of problems by doing more work when you insert your data — which sounds like it would be slow, but Cassandra is designed for fast writes, and you’re probably going to read the data many more times than you write it so it makes sense when you consider the … Read more
I remembered seeing someone answer this question in the Cassandra user mailing list a short while back, but I cannot find the exact message right now. Ironically, Cassandra Evangelist Rebecca Mills just posted an article that addresses this issue (Things you should be doing when using Cassandra drivers…points #13 and #22). But the answer is … Read more
There is a lot of confusion around this, I will try to make it as simple as possible. The primary key is a general concept to indicate one or more columns used to retrieve data from a Table. The primary key may be SIMPLE and even declared inline: create table stackoverflow_simple ( key text PRIMARY … Read more