The main highlight of this new snapshot is that it introduces the opportunity
for queries to opt out of caching. In case a query opts out of caching, not only
will it never be cached, but also no compound query that wraps it will be
cached.
Most notable changes:
- better update concurrency: LUCENE-7868
- TopDocs.totalHits is now a long: LUCENE-7872
- QueryBuilder does not remove the boolean query around multi-term synonyms:
LUCENE-7878
- removal of Fields: LUCENE-7500
For the `TopDocs.totalHits` change, this PR relies on the fact that the encoding
of vInts and vLongs are compatible: you can write and read with any of them as
long as the value can be represented by a positive int.
This snapshot has faster range queries on range fields (LUCENE-7828), more
accurate norms (LUCENE-7730) and the ability to use fake term frequencies
(LUCENE-7854).
We want to upgrade to Lucene 7 ahead of time in order to be able to check whether it causes any trouble to Elasticsearch before Lucene 7.0 gets released. From a user perspective, the main benefit of this upgrade is the enhanced support for sparse fields, whose resource consumption is now function of the number of docs that have a value rather than the total number of docs in the index.
Some notes about the change:
- it includes the deprecation of the `disable_coord` parameter of the `bool` and `common_terms` queries: Lucene has removed support for coord factors
- it includes the deprecation of the `index.similarity.base` expert setting, since it was only useful to configure coords and query norms, which have both been removed
- two tests have been marked with `@AwaitsFix` because of #23966, which we intend to address after the merge
* Upgrade to Lucene 6.4.0
`ValueSource`s are now converted to `DoubleValueSource`s using the Lucene adapter made for the migration to the new API in 6.4.0.
Set lucene version to 6.4.0-snapshot-ec38570 and update all the sha1s/license
Fix invalid combo after upgrade in query_string query. split_on_whitespace=false is disallowed if auto_generate_phrase_queries=true
Adapt the expectations of some tests to the new format of the Lucene explain output
Since Lucene 6.2. the UkrainianMorfologikAnalyzer is available through the
lucene-analyzers-morfologik jar. This change exposes it to be used as an
elasticsearch plugin.
Adrien Grand
Colin Goodheart-Smithe
Md. Abdulla-Al-Sun
Martijn van Groningen
Jason Tedor
Nicholas Knize
Jim Ferenczi
Christoph Büscher