Changes the `Index.CreateFrame()` function to use the `TimeQuantum`
field in the options. If it is blank then it is defaulted to the
time quantum of the index.
Previously, multiple frames with different prefixes were used to separate
different data layouts. This included separating standard row/column
layouts from inverted column/row layouts as well as storing aggregate
information for timestamp data.
Unfortunately, this caused frame meta data to be copied between multiple
frames and it made it difficult to keep these frames in sync.
This commit separates these different physical layouts into `Views`.
A `Frame` now has one or more views which represent each layout.
Fragments have been moved from under the `Frame` to be contained
within the `View`.
There are two primary views:
- `standard`
- `inverse`
If a frame has a time quantum, then views are generated for these
each of the standard/inverse views. For example a time quantum
of `YMDH` for the date `2000-01-02T00:00:00Z` would create the
following views:
- `standard_2000`
- `inverse_2000`
- `standard_200001`
- `inverse_200001`
- `standard_20000102`
- `inverse_20000102`
From the user's perspective, nothing should change in PQL. Different
PQL statements will handle the appropriate view automatically. For
example, `Bitmap()` and `Profile()` will fetch using the `standard`
view or the `inverse` view, respectively. The `Range()` statement
will lookup the appropriate time-based views automatically.
Databases and frames now require explicit creation and have the
option of setting row & column labels. If no labels are provided
then the default `id` and `profileID` labels are used.
This changes the API of the types but does not alter the functionality
since only the `context.Background()` is currently being used. Adding
`Context` will help handle fault tolerance in the future by allowing
timeouts to be propagated across calls to different nodes.
This commit moves the cache flush to the `Index` and only serializes
a single fragment at a time.
Also included in this commit is the `inspect` command for the
`pilsoactl` binary. This provides insight into pilosa data files.
This commit refactors the anti-entropy system to fetch data from
all replicated blocks and only set/clear bits which deviate from
the consensus between all blocks.
An example of this is if 3 nodes had the following bits set for
a single bitmap:
Node A: 1 2 3
Node B: 2 4
Node C: 1 2 4
Then only bits which are set on a majority will be set. In this
case bits 1, 2, & 4 are set but 3 only exists on a single node.
The node performing the merge would then determine the following
set/clear diffs for each node:
Node A: clear(3), set(4)
Node B: set(1)
Node C: none
Once the merge is performed and all nodes receive their diff
instructions then the nodes will be in sync:
Node A: 1 2 4
Node B: 1 2 4
Node C: 1 2 4
There still exists situations where bits can be reset. If Node A
is up and Node B & C are down then Node A's bits will be reset
once B & C come back online. We should add write consistency
settings for incoming writes so that we can ensure that a quorum
is written to before returning a success. This is outside the
scope of this commit though.
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.
