Hello, I've set up a testing evironment for Cassandra and MySQL, to compare both, regarding *performance only*. And I must admit that I was expecting Cassandra to beat MySQL. But I've not seen this happening up to now. My application/use case is INSERT intensive, since I'm not updating anything, just inserting all the time. To compare both I created virtual machines with Ubuntu 11.10, and installed the latest versions of each datastore. Each VM has 1GB of RAM. I've used VMs as a way to give both datastores an equal sandbox. MySQL is set up to work as sharded, with 2 databases, that means that records are inserted to a specific instance based on key % 2. The engine is MyISAM (InnoDB was really slow and not really needed to my case). There's a primary compound key (integer and datetime columns) in this test table. Let's name the "nodes" MySQL1 and MySQL2. Cassandra is set up to work with 4 nodes, with keys (tokens) set up to distribute records evenly across the 4 nodes (nodetool ring reports 25% to each node), replication factor 1 and RandomPartitioner, the other configs are left to default. Let's name the nodes Cassandra1, Cassandra2, Cassandra3 and Cassandra4.
I'm using 2 physical machines (Windows7) to host the 4 (Cassandra) or 2 (MySQL) virtual machines, this way: Machine1: MySQL1, Cassandra1, Cassandra3 Machine2: MySQL2, Cassandra2, Cassandra4 The machines have CPU and RAM enough to host Cassandra Cluster or MySQL "Cluster" at a time. The client test applicatin is running in a third physical machine, with 8 threads doing inserts. The test application is written in C# (Windows7) using Aquiles high-level client. My use case is a vehicle tracking system. So, let's suppose, from minute to minute, the vehicle sends its position together with some other GPS data and vehicle status information. The columns in my Cassandra cluster are just the DateTime (long value) of a position for a specific vehicle, and the value is all the other data serialized to binary format. Therefore, my CF really grows in columns number. So all data is inserted only to one CF/Table named Positions. The key to Cassandra is the VehicleID and to MySQL VehicleID + PositionDateTime (MySQL creates an index to this automatically). Important to note that MySQL threw tons of connection exceptions, even though, the insert was retried until it got through MySQL. My test case was to insert 1k positions for 1k vehicles to 10 days - which gives 10.000.000 of inserts. The final thoughtput that my application had for this scenario was: Cassandra x 4 2012-01-21 11:45:38,044 #6 [Logger.Log] INFO - >> Inserted 10000 positions for 1000 vehicles (10000000 inserts): 2012-01-21 11:45:38,082 #6 [Logger.Log] INFO - >> Total Time: 2:37:03,359 2012-01-21 11:45:38,085 #6 [Logger.Log] INFO - >> Throughput: 1061 inserts/s And for MySQL x 2 2012-01-21 14:26:25,197 #6 [Logger.Log] INFO - >> Inserted 10000 positions for 1000 vehicles (10000000 inserts): 2012-01-21 14:26:25,250 #6 [Logger.Log] INFO - >> Total Time: 2:06:25,914 2012-01-21 14:26:25,263 #6 [Logger.Log] INFO - >> Throughput: 1318 inserts/s Is there something that I'm missing here? Is this excepted? Or the problem is somewhere else and that's hard to say looking at this description? Cheers, Gustavo
