previously we parsed/returned large sections of the documents
back index row in order to compute facet information. this
would require parsing the protobuf of the entire back index row.
unfortunately this creates considerable garbage.
this new version introduces a visitor/callback approach to
working with data inside the back index row. the benefit
of this approach is that we can let the higher-level code
see values, prior to any copies of data being made or
intermediate garbage being created. implementations of
the callback must copy any value which they would like to
retain beyond the callback.
NOTE: this approach is duplicates code from the
automatically generated protobuf code
NOTE: this approach assumes that the "field" field be serialized
before the "terms" field. This is guaranteed by our currently
generated protobuf encoder, and is recommended by the protobuf
spec. But, decoders SHOULD support them occuring in any order,
which we do not.
Previously term entries were encoded pairwise (field/term), so
you'd have data like:
F1/T1 F1/T2 F1/T3 F2/T4 F3/T5
As you can see, even though field 1 has 3 terms, we repeat the F1
part in the encoded data. This is a bit wasteful.
In the new format we encode it as a list of terms for each field:
F1/T1,T2,T3 F2/T4 F3/T5
When fields have multiple terms, this saves space. In unit
tests there is no additional waste even in the case that a field
has only a single value.
Here are the results of an indexing test case (beer-search):
$ benchcmp indexing-before.txt indexing-after.txt
benchmark old ns/op new ns/op delta
BenchmarkIndexing-4 11275835988 10745514321 -4.70%
benchmark old allocs new allocs delta
BenchmarkIndexing-4 25230685 22480494 -10.90%
benchmark old bytes new bytes delta
BenchmarkIndexing-4 4802816224 4741641856 -1.27%
And here are the results of a MatchAll search building a facet
on the "abv" field:
$ benchcmp facet-before.txt facet-after.txt
benchmark old ns/op new ns/op delta
BenchmarkFacets-4 439762100 228064575 -48.14%
benchmark old allocs new allocs delta
BenchmarkFacets-4 9460208 3723286 -60.64%
benchmark old bytes new bytes delta
BenchmarkFacets-4 260784261 151746483 -41.81%
Although we expect the index to be smaller in many cases, the
beer-search index is about the same in this case. However,
this may be due to the underlying storage (boltdb) in this case.
Finally, the index version was bumped from 5 to 7, since smolder
also used version 6, which could lead to some confusion.
This change adds methods that provide access to the actual, underlying
mossStore instance in the bleve/index/store/moss KVStore adaptor.
This enables applications to utilize advanced, mossStore-specific
features (such as partial rollback of indexes). See also
https://issues.couchbase.com/browse/MB-17805
In this commit, I saw that there was a simple incrementBytes()
implementation elsewhere in bleve that seemed simpler than using the
big int package.
Edge case note: if the input bytes would overflow in incrementBytes(),
such as with an input of [0xff 0xff 0xff], it returns nil. moss then
treats a nil endKeyExclusive iterator param as a logical
"higher-than-topmost" key, which produces the prefix iteration
behavior that we want for this edge situation.
Previously bleve allowed you to create a memory-only index by
simply passing "" as the path argument to the New() method.
This was not clear when reading the code, and led to some
problematic error cases as well.
Now, to create a memory-only index one should use the
NewMemOnly() method. Passing "" as the path argument
to the New() method will now return os.ErrInvalid.
Advanced users calling NewUsing() can create disk-based or
memory-only indexes, but the change here is that pass ""
as the path argument no longer defaults you into getting
a memory-only index. Instead, the KV store is selected
manually, just as it is for the disk-based solutions.
Here is an example use of the NewUsing() method to create
a memory-only index:
NewUsing("", indexMapping, Config.DefaultIndexType,
Config.DefaultMemKVStore, nil)
Config.DefaultMemKVStore is just a new default value
added to the configuration, it currently points to
gtreap.Name (which could have been used directly
instead for more control)
closes#427
On a dev laptop, bleve-query benchmark on wiki dataset using
query-string of "+text:afternoon +text:coffee" previously had
throughput of 1222qps, and with this change hits 1940qps.
This change to upside_down term-field-reader no longer moves the
underlying iterator forward preemptively. Instead, it will invoke
Next() on the underlying iterator only when the caller invokes the
term-field-reader's Next().
There's a special case to handle the situation on the first Next()
invocation after the term-field-reader is created.
