Sunday, January 30, 2011

Next version of SimpleDBM

After a break, I have resumed work on creating SimpleDBM V2. This version is mostly a refactoring of the existing codebase to ensure:
  1. Better project structure - break up the project into smaller modules.
  2. Simple IOC container for auto wiring the modules.
  3. TypeSystem now integral part of the core, hence some modules can take advantage of the Row structure; in the current version, the TypeSystem is an add-on component.
  4. Multi-licensed - SimpleDBM V2 will be available under Apache as well as GPL licenses.
  5. Magic number and version info in the SimpleDBM files.
Rather than making enhancements at the same time as refactoring the codebase, I am going to keep changes to a small number, as I want to get the project restructure completed by Q1 2011. 

Moving the type system into the core is the biggest change in SimpleDBM. I think this will allow some modules to exploit the knowledge about rows and column types, and optimise for performance. Some things that may be possible are:
  • Compression of data in pages
  • Smaller redo log records for data updates
Note that the SimpleDBM V2 code is in a separate mercurial repository. Changes can be viewed at