Today if we search across a large amount of shards we hit every shard. Yet, it's quite
common to search across an index pattern for time based indices but filtering will exclude
all results outside a certain time range ie. `now-3d`. While the search can potentially hit
hundreds of shards the majority of the shards might yield 0 results since there is not document
that is within this date range. Kibana for instance does this regularly but used `_field_stats`
to optimize the indexes they need to query. Now with the deprecation of `_field_stats` and it's upcoming removal a single dashboard in kibana can potentially turn into searches hitting hundreds or thousands of shards and that can easily cause search rejections even though the most of the requests are very likely super cheap and only need a query rewriting to early terminate with 0 results.
This change adds a pre-filter phase for searches that can, if the number of shards are higher than a the `pre_filter_shard_size` threshold (defaults to 128 shards), fan out to the shards
and check if the query can potentially match any documents at all. While false positives are possible, a negative response means that no matches are possible. These requests are not subject to rejection and can greatly reduce the number of shards a request needs to hit. The approach here is preferable to the kibana approach with field stats since it correctly handles aliases and uses the correct threadpools to execute these requests. Further it's completely transparent to the user and improves scalability of elasticsearch in general on large clusters.
This change removes the `postings` highlighter. This highlighter has been removed from Lucene master (7.x) because it behaves
exactly like the `unified` highlighter when index_options is set to `offsets`:
https://issues.apache.org/jira/browse/LUCENE-7815
It also makes the `unified` highlighter the default choice for highlighting a field (if `type` is not provided).
The strategy used internally by this highlighter remain the same as before, it checks `term_vectors` first, then `postings` and ultimately it re-analyzes the text.
Ultimately it rewrites the docs so that the options that the `unified` highlighter cannot handle are clearly marked as such.
There are few features that the `unified` highlighter is not able to handle which is why the other highlighters (`plain` and `fvh`) are still available.
I'll open separate issues for these features and we'll deprecate the `fvh` and `plain` highlighters when full support for these features have been added to the `unified`.
Currently global ordinals are documented under `fielddata`. It moves them to
their own file since they also work with doc values and fielddata is on the way
out.
Closes#23101
Fielddata can no longer be configured to be loaded eagerly (it only accepts
`true` and `false`), so this line is a little misleading because it talks about
a procedure we can no longer do.
This commit adds the boolean similarity scoring from Lucene to
Elasticsearch. The boolean similarity provides a means to specify that
a field should not be scored with typical full-text ranking algorithms,
but rather just whether the query terms match the document or not.
Boolean similarity scores a query term equal to its query boost only.
Boolean similarity is available as a default similarity option and thus
a field can be specified to have boolean similarity by declaring in its
mapping:
"similarity": "boolean"
Closes#6731
Since `_all` is now deprecated and cannot be set for new indices, we should also
disallow any field that has the `include_in_all` parameter set.
Resolves#22923
* Grammatical correction
* Add note for legacy string mapping type
* Update truncate token filter to not mention the keyword tokenizer
The advice predates the existence of the keyword field
Closes#22650
This adds a new `normalizer` property to `keyword` fields that pre-processes the
field value prior to indexing, but without altering the `_source`. Note that
only the normalization components that work on a per-character basis are
applied, so for instance stemming filters will be ignored while lowercasing or
ascii folding will be applied.
Closes#18064
Adds `warnings` syntax to the yaml test that allows you to expect
a `Warning` header that looks like:
```
- do:
warnings:
- '[index] is deprecated'
- quotes are not required because yaml
- but this argument is always a list, never a single string
- no matter how many warnings you expect
get:
index: test
type: test
id: 1
```
These are accessible from the docs with:
```
// TEST[warning:some warning]
```
This should help to force you to update the docs if you deprecate
something. You *must* add the warnings marker to the docs or the build
will fail. While you are there you *should* update the docs to add
deprecation warnings visible in the rendered results.
Rename `fields` to `stored_fields` and add `docvalue_fields`
`stored_fields` parameter will no longer try to retrieve fields from the _source but will only return stored fields.
`fields` will throw an exception if the user uses it.
Add `docvalue_fields` as an adjunct to `fielddata_fields` which is deprecated. `docvalue_fields` will try to load the value from the docvalue and fallback to fielddata cache if docvalues are not enabled on that field.
Closes#18943
`stored_fields` parameter will no longer try to retrieve fields from the _source but will only return stored fields.
`fields` will throw an exception if the user uses it.
Add `docvalue_fields` as an adjunct to `fielddata_fields` which is deprecated. `docvalue_fields` will try to load the value from the docvalue and fallback to fielddata cache if docvalues are not enabled on that field.
Closes#18943
Remove the arbitrary limit on epoch_millis and epoch_seconds of 13 and 10
characters, respectively. Instead allow any character combination that can
be converted to a Java Long.
Update the docs to reflect this change.
* Docs: First pass at improving analyzer docs
I've rewritten the intro to analyzers plus the docs
for all analyzers to provide working examples.
I've also removed:
* analyzer aliases (see #18244)
* analyzer versions (see #18267)
* snowball analyzer (see #8690)
Next steps will be tokenizers, token filters, char filters
* Fixed two typos
Adds infrastructure so `gradle :docs:check` will extract tests from
snippets in the documentation and execute the tests. This is included
in `gradle check` so it should happen on CI and during a normal build.
By default each `// AUTOSENSE` snippet creates a unique REST test. These
tests are executed in a random order and the cluster is wiped between
each one. If multiple snippets chain together into a test you can annotate
all snippets after the first with `// TEST[continued]` to have the
generated tests for both snippets joined.
Snippets marked as `// TESTRESPONSE` are checked against the response
of the last action.
See docs/README.asciidoc for lots more.
Closes#12583. That issue is about catching bugs in the docs during build.
This catches *some* bugs in the docs during build which is a good start.
Colin Goodheart-Smithe
Simon Willnauer
Clinton Gormley
Jim Ferenczi
Andrey Groshev
Adrien Grand
Nik Everett
Lee Hinman
Ali Beyad
Yannick Welsch
Alex
Lee Hinman
Jun Ohtani
Nicholas Knize
David Pilato
Britta Weber
G. Richard Bellamy
Robin Joseph
Dongjoon Hyun
Robert Muir
Rachit Gupta
Imran Azad
Ben Tse