Below definitions are quoted from Akka Documentation at-most-once delivery means that for each message handed to the mechanism, that message is delivered zero or one times; in more casual terms it means that messages may be lost. at-least-once delivery means that for each message handed to the mechanism potentially multiple attempts are made at delivering … Read more
With the advent of CQL3 the terminology has changed slightly from the old thrift terms. Basically Create Table foo (a int , b int, c int, d int, PRIMARY KEY ((a,b),c)) Will make a CQL3 table. The information in a and b is used to make the partition key, this describes which node the information … 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
Answering my own question: Seeds From the FAQ: Seeds are used during startup to discover the cluster. Also from the DataStax documentation on “Gossip”: The seed node designation has no purpose other than bootstrapping the gossip process for new nodes joining the cluster. Seed nodes are not a single point of failure, nor do they … Read more
Wrong syntax. Here you are: insert into user_by_category (game_category,customer_id) VALUES (‘Goku’,’12’); or: insert into user_by_category (“game_category”,”customer_id”) VALUES (‘Kakarot’,’12’); The second one is normally used for case-sensitive column names.
To answer the original question you posed: a column family and a table are the same thing. The name “column family” was used in the older Thrift API. The name “table” is used in the newer CQL API. More info on the APIs can be found here: http://wiki.apache.org/cassandra/API If you need to use “group by,order … Read more
You are likely getting this error because the Replication Factor of the keyspace the table you are querying belongs to has a Replication Factor of one, is that correct? If the partition you are reading / updating does not have enough available replicas (nodes with that data) to meet the consistency level, you will get … Read more
cqlsh> use system; cqlsh:system> select data_center from local; data_center ————- datacenter1
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