To help offer verbatim matches for external link texts, we assign these positions in the document a bit after the actual document ends. Integrating this information with the ranking is not performed here.
The first change, running index construction in parallel, was previously how it was done, but it was changed to run sequentially to see how it would affect performance. It got worse, so the change is reverted.
Though it's been noted that sorting in parallel is likely not a good idea as it leads to a lot of I/O thrashing, so this is changed to be done sequentially.
This lets the slop library be stand-alone without dependence on coded-sequence.
The change also gets rid of the vestigial seek() method in ColumnReader.
The most common error when dealing with Slop columns is that they can fall out of sync with each other if the programmer accidentally does a conditional read and forgets to skip.
The second most common error is forgetting to close one of the columns in a reader or writer.
To deal with both cases, a new class SlopTable is added that keeps track of the lifecycle of all slop columns and performs a check when closing them that they are in sync.
Refactoring keyword extraction to extract spans information.
Modifying the intermediate storage of converted data to use the new slop library, which is allows for easier storage of ad-hoc binary data like spans and positions.
This is a bit of a katamari damacy commit that ended up dragging along a bunch of other fairly tangentially related changes that are hard to break out into separate commits after the fact. Will push as-is to get back to being able to do more isolated work.
Expected behavior changed since the ranking algorithm now takes into account the number of positions of the keyword, and the test loader was previously modified to generate positions based on prime factors of the document id.
Fix rare bug where the takeWhileZero method would fail to repopulate the underlying buffer. This caused intermittent de-compression errors if takeWhileZero happened at a 64 bit boundary while the underlying buffer was empty.
The change also alters how sequence-lengths are encoded, to more consistently use the getGamma method instead of adding special significance to a zero first byte.
Finally, assertions are added checking the invariants of the gamma and delta coding logic as well as UrlIdCodec to earlier detect issues.
The change also restructures the internal API a bit, moving resultsFromDomain from RpcRawResultItem into RpcDecoratedResultItem, as the previous order was driving complexity in the code that generates these objects, and the consumer side of things puts all this data in the same object regardless.
Adding new ranking parameters to the API and routing them through the system, in order to permit integration of the new position data with the ranking algorithm.
The change also cleans out several parameters that no longer filled any function.
The priority index documents file can be trivially compressed to a large degree.
Compression schema:
```
00b -> diff docord (E gamma)
01b -> diff domainid (E delta) + (1 + docord) (E delta)
10b -> rank (E gamma) + domainid,docord (raw)
11b -> 30 bit size header, followed by 1 raw doc id (61 bits)
```
Previously this was the responsibility of the caller, which lead to the possibility of passing in improperly prepared buffers and receiving bad outcome
Btree index adds overhead and disk space and doesn't fill any function for the prio index.
* Update finalize logic with a new IO transformer that copies the data and prepends a size
* Update the reader to read the new format
* Added a test
The term data iterator is quite hot and was performing buffer slice operations that were not necessary.
Replacing with a fixed pointer alias that can be repositioned to the relevant data.
The positions data was also being wrapped in a GammaCodedSequence only to be immediately un-wrapped.
Removed this unnecessary step and move to copying the buffer directly instead.
