Previously the `slice` was not copied to each new segment when
`Intersect()`, `Union()`, and `Difference()` operations were performed.
This causes issues when those bitmaps were then operated on later such
as performing a `TopN()` on a source bitmap.
This commit changes the underlying storage for `Bitmap` from a
red-black tree to a roaring bitmap. It also removes bitmaps from
the cache and only stores the bitmap count.
This commit changes the `pql.Query` so that it can accept one or more
top-level calls instead of only one.
The query request format change because a query with a single call is
still valid. However, the result format now returns a `results` field
that has one result for each top-level call. The `profiles` field is
still the same, however, it combines all profiles from all bitmap
responses into one return so that there's not duplicate attributes.
Fixes#59
This commit adds the ability of the Fragment to flush the cache
bitmap IDs to disk periodically. They can then be reloaded when
the fragment is reopened.
This commit attaches the mmap-backed roaring bitmaps as storage
to the fragments. Currently snapshotting is not supported from
Pilosa so the WAL will grow indefinitely, however, it is not a
difficult change to make.
This commit refactors the pilosa codebase. It makes several major
changes:
* Removes bitmap handles
* Removes dispatch/hold/transport
* Removes etcd dependency
* Adds consistent hash ring for slice placement
* Refactors parser/lexer
* Adds strong typing to PQL AST
* Flattens package hierarchy
