Details
Major Description
DWPTPool currently uses an indirection called ThreadState to hold DWPT instances. This class holds several information that belongs in other places, inherits from ReentrantLock and has a mutable nature. Instead we could pool the DWPT directly and remove other indirections inside DWPTFlushControl if we move some of the ThreadState properties to DWPT directly. The threadpool also has a problem that is grows it's ThreadStates to the number of concurrently indexing threads but never shrinks it if they are reduced. With pooling DWPT directly this limitation could be removed.
In summary, this component has seen quite some refactoring and requires some cleanups and docs changes in order to stay the test of time.
