Tokyo Cabinet Tutorial: Database Types and Configuration Options

A great piece of documentation for the 3 different storage types supported by Tokyo Cabinet: hash, B+ tree and fixed-length. The article also features a long list of tuning parameters.

Here are a couple of things that I’ve learned myself:

• Tokyo Cabinet support multi-operation transactions
• the extension of the file determines the type of storage:
  • tch: Tokyo Cabinet Hash database
  • tcb: Tokyo Cabinet B+Tree database
  • tcf: Tokyo Cabinet Fixed-Length database
• while Tokyo Cabinet B+Tree storage might be a bit slower than Tokyo Cabinet Hash storage, it brings new features:
  • keys are ordered (default lexical, but can be configured by passing a comparison function)
  • as a consequence it supports key ranges
  • allows duplicate values to be stored under the same key
• Tokyo Cabinet Fixed-Length has some restrictions:
  • all keys are positive integers
  • as Tokyo Cabinet B+Tree keys are ordered (based on the integer keys) and it is not configurable
  • all values stored have fixed-length
• on the bright side, Tokyo Cabinet Fixed-Length support some special keys: :min, :max, :prev and :next.

I think this is a great contribution by James Edward Gray II to the Tokyo Cabinet community which is facing some problems including the lack of documentation.

via: http://blog.grayproductions.net/articles/tokyo_cabinets_keyvalue_database_types