This is a full backport of Drupal 7 core cache.inc for Drupal 6. It works as-is a drop-in replacement, without having any patch to do over core.
It allows usage of multiple cache backends on the same site (example: you could use APC backend for critical cache tables, memcache for page caching, and let the others live on database).
The Drupal 7 cache.inc file has been copied as-is as the provided file, with only two patches:
- The database default backend as been moved to its own file, because it has been severly patched in order to gracefully downgrade to D6 database layer.
- At the end of file, every declared cache backend file is loaded because we don't have an autoloader function.
Installation is quite simple and fully documented in INSTALL.txt file provided in the module package.