the index mapping contains some relatively messy logic
and the top-level bleve package only cares about a relatively
small portion of this
the motivation for this change is to codify the part that the
top-level bleve package cares about into an interface
then move all the details into its own package
NOTE: the top-level bleve package still has hard dependency on
the actual implementation (for now) because it must deserialize
mappings from JSON and simply assumes it is this one instance.
this is seen as OK for now, and this issue could be revisited
in a future change. moving the logic into a separate package
is seen as a simplification of top-level bleve, even though
we still depend on the one particular implementation.
In the index/store package
introduce KVReader
creates snapshot
all read operations consistent from this snapshot
must close to release
introduce KVWriter
only one writer active
access to all operations
allows for consisten read-modify-write
must close to release
introduce AssociativeMerge operation on batch
allows efficient read-modify-write
for associative operations
used to consolidate updates to the term summary rows
saves 1 set and 1 get op per shared instance of term in field
In the index package
introduced an IndexReader
exposes a consisten snapshot of the index for searching
At top level
All searches now operate on a consisten snapshot of the index
this started initially to relocate highlighting into
a self contained package, which would then also use
the registry
however, it turned into a much larger refactor in
order to avoid cyclic imports
now facets, searchers, scorers and collectors
are also broken out into subpackages of search
ultimately this is make it more convenient for us to wire up
different elements of the analysis pipeline, without having to
preload everything into memory before we need it
separately the index layer now has a mechanism for storing
internal key/value pairs. this is expected to be used to
store the mapping, and possibly other pieces of data by the
top layer, but not exposed to the user at the top.
