Internal KeySet Cache

When doing kdbGet() possible more keys are returned which might be confusing. When doing a second kdbGet() with a new keyset no keys might be returned, because it is up-to-date.

When doing kdbSet() a deep duplication is needed.

Idea: keep a duplicated keyset internally. Return (non-deep?) duplications exactly of the parts as requested.

• no cache (current situation)
• flat cache with COW
• deep duplicated cache
• Use global plugin to implement internal cache.
• Use global mmap plugin and make kdbGet() to always retrieve everything.

Not yet decided.

Semantics can be provided without additional code or overhead in the core.

• Global Validation

internal caches lead to duplication of memory consumption (most of it is avoided by reference counting, though)

in some cases caches cannot be avoided? -> filesys, databases?

Pros:

• not more keys than needed
• kdbGet avoids IO even if done somewhere else
• KDB handles could be more locally

Cons:

• not possible to access cache with current architecture, KDB high level API
• implementation overhead
• where should the caches be