The zap DictionaryIterator Next() was incorrectly returning the
postingsList offset as the term count. As part of this, refactored
out a PostingsList.read() helper method.
Also added more merge unit test scenarios, including merging a segment
for a few rounds to see if there are differences before/after merging.
Instead of sorting docNum keys from a hashmap, this change instead
iterates from docNum 0 to N and uses an array instead of hashmap.
The array is also reused across outer loop iterations.
This optimizes for when there's a lot of structural similarity between
docs, where many/most docs have the same fields. i.e., beers,
breweries. If every doc has completely different fields, then this
change might produce worse behavior compared to the previous sparse
hashmap approach.
Instead of allocating a govarint.U64Base128Encoder in the inner loop,
allocate it just once on the outside, as it appears that it's just a
thin wrapper around binary.PutUvarint().
The zap SegmentBase struct is a refactoring of the zap Segment into
the subset of fields that are needed for read-only ops, without any
persistence related info. This allows us to use zap's optimized data
encoding as scorch's in-memory segments.
The zap Segment struct now embeds a zap SegmentBase struct, and layers
on persistence. Both the zap Segment and zap SegmentBase implement
scorch's Segment interface.
+ Account for all the overhead incurred from the data structures
within mem.Segment and zap.Segment.
- SizeOfMap = 8
- SizeOfPointer = 8
- SizeOfSlice = 24
- SizeOfString = 16
+ Include overhead from certain new fields as well.
This change preallocates more of the backing arrays for Locfields,
Locstarts, Locends, Locpos, Locaaraypos sub-slices of a scorch mem
segment.
On small bleve-blast tests (50K wiki docs) on a dev macbook, scorch
indexing throughput seems to improve from 15MB/sec to 20MB/sec after
the recent series of preallocation changes.
The scorch mem segment build phase uses the append() idiom to populate
various slices that are keyed by postings list id's. These slices
include...
* Postings
* PostingsLocs
* Freqs
* Norms
* Locfields
* Locstarts
* Locends
* Locpos
* Locarraypos
This change introduces an initialization step that preallocates those
slices up-front, by assigning postings list id's to terms up-front.
This change also has an additional effect of simplifying the
processDocument() logic to no longer have to worry about a first-time
initialization case, removing some duplicate'ish code.
The first time through, startNumFields should be 0, where there ought
to be more optimization assuming later docs have similar fields as the
first doc.
-VisitableDocValueFields API for persisted DV field list
-making dv configs overridable at field level
-enabling on the fly/runtime un inverting of doc values
-few UT updates
previous approach used SetEventCallback method which allowed
you to change the callback, unfotunately that also included
times after the goroutines were started and potentially firing
the callback.
checking lock on this would be too expensive, so instead we go
for an approach that allows callbacks to be registered by name
during process init(), then upon opening up an index a string
config key 'eventCallbackName' is used to look up the
appropriate callback function. also, since this string config
name is serializable, it fits into the existing bleve index
metadata without any new issues.
zap command-line tool added to main bleve command-line tool
this required physical relocation due to the vendoring used
only on the bleve command-line tool (unforseen limitation)
a new scorch command-line tool has also been introduced
and for the same reasons it is physically store under
the top-level bleve command-line tool as well
New APIs:
+ RollbackPoints()
- Retrieves the available list of rollback points: epoch+meta.
- The application will need to check with the meta to decide
on the rollback point.
+ Rollback()
- API requires a rollback point identified by the first API.
- Atomically & Durably rolls back the index to specified point,
provided the specified rollback point is still available.
+ Unit test: TestIndexRollback
- Writes a batch.
- Sets the rollback point.
- Writes second batch.
- Rollback to previously decided point.
- Ensure that data is as is before the second batch.
inserted to the list of dv enabled fields list -
DocValueFields in mem segment.
Moved back to the original type `DocValueFields map[uint16]bool`
for easy look up to check whether the fieldID is
configured for dv storage.