This is a proposal to deprecate existing Hash Index and deprecate the create hash index apis.
Currently the Hash Index name causes confusion. It is not a traditional hash look up index, but more of memory savings index. The index does not store index keys in memory and must hash the keys every time. The index synchronizes on a backing array and when the backing array needs to be expanded, it currently needs to rehash all elements in the array. This can be very problematic for larger data sets. There were improvements made to one of the functional indexes (compact range index) prior to open sourcing. These improvements helped reduce the memory consumption of that index and makes it very similar sized to a hash index, but the keys still are stored in memory. Probably close enough to be a replacement for the hash index in most cases. The read/write performance on it is also faster than the hash index. If anyone has any objections, please let us know and why. Thanks, - Jason
