Tantivy v0.18

• For date values chrono has been replaced with time (@uklotzde) #1304
• Add histgram aggregation (@PSeitz)
• Add support for fastfield on text fields (@PSeitz)
• Add terms aggregation (@PSeitz)
• Add support for zstd compression (@kryesh)

Tantivy v0.17

• LogMergePolicy now triggers merges if the ratio of deleted documents reaches a threshold (@shikhar @fulmicoton) #115
• Adds a searcher Warmer API (@shikhar @fulmicoton)
• Change to non-strict schema. Ignore fields in data which are not defined in schema. Previously this returned an error. #1211
• Facets are necessarily indexed. Existing index with indexed facets should work out of the box. Index without facets that are marked with index: false should be broken (but they were already broken in a sense). (@fulmicoton) #1195 .
• Bugfix that could in theory impact durability in theory on some filesystems #1224
• Schema now offers not indexing fieldnorms (@lpouget) #922
• Reduce the number of fsync calls #1225
• Fix opening bytes index with dynamic codec (@PSeitz) #1278
• Added an aggregation collector compatible with Elasticsearch (@PSeitz)
• Added a JSON schema type @fulmicoton #1251
• Added support for slop in phrase queries @halvorboe #1068

Tantivy v0.16.1

Major Bugfix on multivalued fastfield. #1151

Tantivy 0.15.3

• Major bugfix. Deleting documents was broken when the index was sorted by a field. (@appaquet, @fulmicoton) #1101

Tantivy 0.15.2

• Major bugfix. DocStore still panics when a deleted doc is at the beginning of a block. (@appaquet) #1088

Tantivy 0.15.1

• Major bugfix. DocStore panics when first block is deleted. (@appaquet) #1077

Tantivy 0.15

• API Changes. Using Range instead of (start, end) in the API and internals (FileSlice, OwnedBytes, Snippets, ...)
  This change is breaking but migration is trivial.
• Added an Histogram collector. (@fulmicoton) #994
• Added support for Option. (@fulmicoton)
• DocAddress is now a struct (@scampi) #987
• Bugfix consistent tie break handling in facet's topk (@hardikpnsp) #357
• Date field support for range queries (@rihardsk) #516
• Added lz4-flex as the default compression scheme in tantivy (@PSeitz) #1009
• Renamed a lot of symbols to avoid all uppercasing on acronyms, as per new clippy recommendation. For instance, RAMDirectory -> RamDirectory. (@fulmicoton)
• Simplified positions index format (@fulmicoton) #1022
• Moved bitpacking to bitpacker subcrate and add BlockedBitpacker, which bitpacks blocks of 128 elements (@PSeitz) #1030
• Added support for more-like-this query in tantivy (@evanxg852000) #1011
• Added support for sorting an index, e.g presorting documents in an index by a timestamp field. This can heavily improve performance for certain scenarios, by utilizing the sorted data (Top-n optimizations)(@PSeitz). #1026
• Add iterator over documents in doc store (@PSeitz). #1044
• Fix log merge policy (@PSeitz). #1043
• Add detection to avoid small doc store blocks on merge (@PSeitz). #1054
• Make doc store compression dynamic (@PSeitz). #1060
• Switch to json for footer version handling (@PSeitz). #1060
• Updated TermMerger implementation to rely on the union feature of the FST (@scampi) #469
• Add boolean marking whether position is required in the query_terms API call (@fulmicoton). #1070

Tantivy 0.14

• Remove dependency to atomicwrites #833 .Implemented by @fulmicoton upon suggestion and research from @asafigan).
• Migrated tantivy error from the now deprecated failure crate to thiserror #760. (@Hirevo)
• API Change. Accessing the typed value off a Schema::Value now returns an Option instead of panicking if the type does not match.
• Large API Change in the Directory API. Tantivy used to assume that all files could be somehow memory mapped. After this change, Directory return a FileSlice that can be reduced and eventually read into an OwnedBytes object. Long and blocking io operation are still required by they do not span over the entire file.
• Added support for Brotli compression in the DocStore. (@ppodolsky)
• Added helper for building intersections and unions in BooleanQuery (@guilload)
• Bugfix in Query::explain
• Removed dependency on notify #924. Replaced with FileWatcher struct that polls meta file every 500ms in background thread. (@halvorboe @guilload)
• Added FilterCollector, which wraps another collector and filters docs using a predicate over a fast field (@barrotsteindev)
• Simplified the encoding of the skip reader struct. BlockWAND max tf is now encoded over a single byte. (@fulmicoton)
• FilterCollector now supports all Fast Field value types (@barrotsteindev)
• FastField are not all loaded when opening the segment reader. (@fulmicoton)

This version breaks compatibility and requires users to reindex everything.

Tantivy 0.13.3

Minor Bugfix. Avoid relying on serde's reexport of PhantomData. (#975)

Tantivy 0.13.2

HotFix. Acquiring a facet reader on a segment that does not contain any
doc with this facet returns None. (#896)