Is Cassandra a good candidate database for that must sustain over 100 read/write operations per second?

Question

Currently our system uses PostgreSQL, however we seem to have pushed the limit of its capabilities. Some of our tables need to handle over 100 read/write operations per second so it is probably time to scale horizontally across multiple machines.

Have a lot of experience using GAE's Big Table. Big Table had rich options for querying. For example, queries were possible against list data fields. Cassandra is supposed to be based off of Big Table, but if I understand correctly, for Cassandra, we will actually have to custom-code a layer on top of Cassandra that uses and maintains index tables.

Would be great if there was an open source database available for which we did not have to build our own custom logic for maintaining index tables, zig-zag merge joins, etc...

Is Cassandra a good candidate here? Or are there ones that might be considered better?

Answer 1

Unless the operations are huge joins or return hundreds of thousands of rows, any database you choose will be able to sustain 100 ops/s. Cassandra will have no problems serving thousands if not tens of thousands of reads and writes per node.

Without knowing more about your particular use case it's impossible to give you meaningful advice. Cassandra is a great database, but if it's right for you I don't know. I'd suggest looking through the cassandra tag here on Stack Overflow and look at what people ask about and if it looks at all like what you're trying to do, and if the answers say that it's possible with Cassandra (I know I've answered quite a few questions where the answer was that Cassandra wasn't the best choice for that particular case).

Cassandra and GAE Big Table have big similarities, but also big differences. One thing that trips up new Cassandra users is that there really isn't any way of doing things like "add this thing only unless that other thing was there" or "add an item and remove all but the last N items".