In order to be consistent (and because in 1.0 we switched from
parameter driven information to specifzing the metrics as part of the URI)
this patch moves from 'plugin' to 'plugins' in the Nodes Info API.
`cross_fields` attemps to treat fields with the same analysis
configuration as a single field and uses maximum score promotion or
combination of the scores based depending on the `use_dis_max` setting.
By default scores are combined. `cross_fields` can also search across
fields of hetrogenous types for instance if numbers can be part of
the query it makes sense to search also on numeric fields if an analyzer
is provided in the reqeust.
Relates to #2959
* Mostly minor things like typos and grammar stuff
* Some clarifications
* The note on the deprecation was ambiguous. I've removed the problematic part so that it now definitely says it's deprecated
Currently, boosting on `copy_to` is misleading and does not work as originally specified in #4520. Instead of boosting just the terms from the origin field, it boosts the whole destination field. If two fields copy_to a third field, one with a boost of 2 and another with a boost of 3, all the terms in the third field end up with a boost of 6. This was not the intention.
The alternative: to store the boost in a payload for every term, results in poor performance and inflexibility. Instead, users should either (1) query the common field AND the field that requires boosting, or (2) the multi_match query will soon be able to perform term-centric cross-field matching that will allow per-field boosting at query time (coming in 1.1).
By default active, rejected and queue thread statistics are included for the index, bulk and search thread pool.
Other thread statistics of other thread pools can be included via the `h` query string parameter.
Closes#4907
Detects if rescores arrive as an array instead of a plain object. If so
then parse each element of the array as a separate rescore to be executed
one after another. It looks like this:
"rescore" : [ {
"window_size" : 100,
"query" : {
"rescore_query" : {
"match" : {
"field1" : {
"query" : "the quick brown",
"type" : "phrase",
"slop" : 2
}
}
},
"query_weight" : 0.7,
"rescore_query_weight" : 1.2
}
}, {
"window_size" : 10,
"query" : {
"score_mode": "multiply",
"rescore_query" : {
"function_score" : {
"script_score": {
"script": "log10(doc['numeric'].value + 2)"
}
}
}
}
} ]
Rescores as a single object are still supported.
Closes#4748
Removed unused misc.asciidoc file
Added plugins directory to directory layout
Fixed transport.tcp.connect_timeout value to match the code found in NetworkService.TcpSettings
Clarified that phrase query does not preserve order of terms
Clarified merge page
Added instructions on how to build documentation to docs/README
Terms aggregations return up to `size` terms, so up to now, the way to get all
matching terms back was to set `size` to an arbitrary high number that would be
larger than the number of unique terms.
Terms aggregators already made sure to not allocate memory based on the `size`
parameter so this commit mostly consists in making `0` an alias for the
maximum integer value in the TermsParser.
Close#4837
Adds a new FetchSubPhase, FieldDataFieldsFetchSubPhase, which loads the
field data cache for a field and returns an array of values for the
field.
Also removes `doc['<field>']` and `_source.<field>` workaround no longer
needed in field name resolving.
Closes#4492
* Make it clearer that `aggs` is an allowed synomym
for the `aggregations` key
* Fix broken example in for datehistogram, `1.5M` is
not an allowed interval
* Make use of colon before examples consistent
* Fix typos
- Removed "ok": true from response examples
- Added "created" flag to index response examples
- Replaced exists flag with found in delete response examples
* Made GET mappings consistent, supporting
* /{index}/_mappings/{type}
* /{index}/_mapping/{type}
* /_mapping/{type}
* Added "mappings" in the JSON response to align it with other responses
* Made GET warmers consistent, support /{index}/_warmers/{type} and /_warmer, /_warner/{name}
as well as wildcards and _all notation
* Made GET aliases consistent, support /{index}/_aliases/{name} and /_alias, /_aliases/{name}
as well as wildcards and _all notation
* Made GET settings consistent, added /{index}/_setting/{name}, /_settings/{name}
as well as supportings wildcards in settings name
* Returning empty JSON instead of a 404, if a specific warmer/
setting/alias/type is missing
* Added a ton of spec tests for all of the above
* Added a couple of more integration tests for several features
Relates #4071
See issue #4071
PUT options for _mapping:
Single type can now be added with
`[PUT|POST] {index|_all|*|regex|blank}/[_mapping|_mappings]/type`
and
`[PUT|POST] {index|_all|*|regex|blank}/type/[_mapping|_mappings]`
PUT options for _warmer:
PUT with a single warmer can now be done with
`[PUT|POST] {index|_all|*|prefix*|blank}/{type|_all|*|prefix*|blank}/[_warmer|_warmers]/warmer_name`
PUT options for _alias:
Single alias can now be PUT with
`[PUT|POST] {index|_all|*|prefix*|blank}/[_alias|_aliases]/alias`
DELETE options _mapping:
Several mappings can be deleted at once by defining several indices and types with
`[DELETE] /{index}/{type}`
`[DELETE] /{index}/{type}/_mapping`
`[DELETE] /{index}/_mapping/{type}`
where
`index= * | _all | glob pattern | name1, name2, …`
`type= * | _all | glob pattern | name1, name2, …`
Alternatively, the keyword `_mapings` can be used.
DELETE options for _warmer:
Several warmers can be deleted at once by defining several indices and names with
`[DELETE] /{index}/_warmer/{type}`
where
`index= * | _all | glob pattern | name1, name2, …`
`type= * | _all | glob pattern | name1, name2, …`
Alternatively, the keyword `_warmers` can be used.
DELETE options for _alias:
Several aliases can be deleted at once by defining several indices and names with
`[DELETE] /{index}/_alias/{type}`
where
`index= * | _all | glob pattern | name1, name2, …`
`type= * | _all | glob pattern | name1, name2, …`
Alternatively, the keyword `_aliases` can be used.
Fixes#4701. Changes behavior of the snapshot operation. The operation now fails if not all primary shards are available at the beginning of the snapshot operation. The restore operation no longer tries to restore indices with shards that failed or were missing during snapshot operation.
Currently it is possible to index a document as:
```
POST /myindex/mytype/1
{ "foo"...}
```
or as:
```
POST /myindex/mytype/1
{
"mytype": {
"foo"...
}
}
```
This makes indexing non-deterministic and fields can be misinterpreted
as type names.
This changes makes Elasticsearch accept only the first form by default,
ie without the type wrapper. This can be changed by setting
`index.mapping.allow_type_wrapper` to `true`` when creating the index.
Closes#4484
When set to false a new strict mode of parsing is employed which
a) does not permit numbers to be passed as JSON strings in quotes
b) rejects numbers with fractions that are passed to integer, short or long fields.
Closes#4117
Java Builder apis drop old “len” methods in favour of new “length”
Rest APIs support both old “len: and new “length” forms using new ParseField class to a) provide compiler-checked consistency between Builder and Parser classes and
b) a common means of handling deprecated syntax in the DSL.
Documentation and rest specs only document the new “*length” forms
Closes#4083
`standard_html_strip` and `pattern` analyzer support stopwords which are
set to the default `english` stopwords by default. Those analyzers
should not use stopwords by default since they are language neutral
Closes#4699
`min_doc_count` is the minimum number of hits that a term or histogram key
should match in order to appear in the response.
`min_doc_count=0` replaces `compute_empty_buckets` for histograms and will
behave exactly like facets' `all_terms=true` for terms aggregations.
Close#4662
When upgrading to ES 1.0 the existing mappings with a multi-field type automatically get replaced to a core field with the new `fields` option.
If a `multi_field` type-ed field doesn't have a main / default field, a default field will be chosen for the multi fields syntax. The new main field type
will be equal to the first `multi_field` fields' field or type string if no fields have been configured for the `multi_field` field and in both cases
the default index will not be indexed (`index=no` is set on the default field).
If a `multi_field` typed field has a default field, that field will replace the `multi_field` typed field.
Closes to #4521
============
The default unit for measuring distances is *MILES* in most cases. This commit moves ES
over to the *International System of Units* and make it work on a default which relates
to *METERS* . Also the current structures of the `GeoBoundingBox Filter` changed in
order to define the *Bounding* by setting abitrary corners.
Distances
---------
Since the default unit for measuring distances has changed to a default unit
`DistanceUnit.DEFAULT` relating to *meters*, the **REST API** has changed at the
following places:
* `ScriptDocValues.factorDistance()` returns *meters* instead of *miles*
* `ScriptDocValues.factorDistanceWithDefault()` returns *meters* instead of *miles*
* `ScriptDocValues.arcDistance()` returns *meters* instead of *miles*
one might use `ScriptDocValues.arcDistanceInMiles()`
* `ScriptDocValues.arcDistanceWithDefault()` returns *meters* instead of *miles*
* `ScriptDocValues.distance()` returns *meters* instead of *miles*
one might use `ScriptDocValues.distanceInMiles()`
* `ScriptDocValues.distanceWithDefault()` returns *meters* instead of *miles*
one might use `ScriptDocValues.distanceInMilesWithDefault()`
* `GeoDistanceFilter` default unit changes from *kilometers* to *meters*
* `GeoDistanceRangeFilter` default unit changes from *miles* to *meters*
* `GeoDistanceFacet` default unit changes from *miles* to *meters*
Geo Bounding Box Filter
-----------------------
The naming of the GeoBoundingBoxFilter properties allows to set arbitrary corners
(see #4084) namely `top_right`, `top_left`, `bottom_right` and `bottom_left`. This
change also includes the fields `topRight` and `bottomLeft` Also it is be possible to
set the single values by using just `top`, `bottom`, `left` and `right` parameters.
Closes#4515, #4084
Also changes the response format of that section to:
```
"open_file_descriptors": {
"min": 200,
"max": 346,
"avg": 273
}
```
Closes#4681
Note: this is an aggregate of 3 commits in the 0.90 branch
A lot of different API's currently use different names for the
same logical parameter. Since lucene moved away from the notion
of a `similarity` and now uses an `fuzziness` we should generalize
this and encapsulate the generation, parsing and creation of these
settings across all queries.
This commit adds a new `Fuzziness` class that handles the renaming
and generalization in a backwards compatible manner.
This commit also added a ParseField class to better support deprecated
Query DSL parameters
The ParseField class allows specifying parameger that have been deprecated.
Those parameters can be more easily tracked and removed in future version.
This also allows to run queries in `strict` mode per index to throw
exceptions if a query is executed with deprected keys.
Closes#4082
`allocation.disable_new_allocation`, `allocation.disable_allocation`, `allocation.disable_replica_allocation`,
in favour for the enable allocation decider which has a single option `allocation.enable` wich can be set to the following values:
`none`, `new_primaries`, `primaries` and `all` (default).
Closes#4488
The new internal get index settings api is more efficient when it comes to sending the index settings from the master to the client via the
Also the get index settings support now all the indices options.
Closes#4620
The FVH was throwing away some boosts on queries stopping a number of
ways to boost phrase matches to the top of the list of fragments from
working.
The plain highlighter also doesn't work for this but that is because it
doesn't support the concept of the same term having a different score at
different positions.
Also update documentation claiming that FHV is nicer for weighing terms
found by query combinations.
Closes#4351
Important: This breaks backwards compatibility with 0.90
* Removed endpoints: /_cluster/nodes, /_cluster/nodes/nodeId1,nodeId2
* Disallow usage of parameters, but make required metrics part of URI
* Changed NodesInfoRequest to return everything by default
* Fixed NPE in NodesInfoResponse
Closes#4055
Instead of specifying what kind of data should be filtered, this commit
streamlines the API to actually specify, what kind of data should be displayed.
This makes its behaviour similar to the other requests, like NodeIndicesStats.
A small feature has been added as well: If you specify an index to select on, not
only the metadata, but also the routing tables are filtered by index in order
to prevent too big cluster states to be returned.
Also the CAT apis have been changed to only return the wanted data in order to keep
network traffic as small as needed.
Tests for the cluster state API filtering have been added as well.
Note: This change breaks backwards compatibility with 0.90!
Closes#4065
Added a long-based representation of GeoHashes to GeoHashUtils for fast evaluation in aggregations.
The new BucketUtils provides a common heuristic for determining the number of results to obtain from each shard in "top N" type requests.
* Clean up s/ElasticSearch/Elasticsearch on docs/*
* Clean up s/ElasticSearch/Elasticsearch on src/* bin/* & pom.xml
* Clean up s/ElasticSearch/Elasticsearch on NOTICE.txt and README.textile
Closes#4634
Norms can be eagerly loaded on a per-field basis by setting norms.loading to
`eager` instead of the default `lazy`:
```
"my_string_field" : {
"type": "string",
"norms": {
"loading": "eager"
}
}
```
In case this behavior should be applied to all fields, it is possible to change
the default value by setting `index.norms.loading` to `eager`.
Close#4079
First, this breaks backwards compatibility!
* Removed /_cluster/nodes/stats endpoint
* Excpect the stats types not as parameters, but as part of the URL
* Returning all indices stats by default, returning all nodes stats by default
* Supporting groups & types in nodes stats now as well
* Updated documentation & tests accordingly
* Allow level parameter for "shards" and "indices" (cluster does not make sense here)
Closes#4057
Note: This breaks backward compatibility
* Removed clear/all parameters, now all stats are returned by default
* Made the metrics part of the URL
* Removed a lot of handlers
* Added shards/indices/cluster level paremeter to change response serialization
* Returning translog statistics in IndicesStats
* Added TranslogStats class
* Added IndexShard.translogStats() method to get the stats from concrete implementation
* Updated documentation
Closes#4054
The reason to not start packages on installation is to allow to configure
them before starting up (setting heap, cluster.name etc)
Also the documentation was updated in order to show, which statements need
to be executed.
In addition, these statements are also printed out when the package is
installed, depending on whether chkconfig, system or update-rc.d is used.
Closes#3722
When testing plugin manager with real downloads, it could happen that the test run forever. Fortunately, test suite will be interrupted after 20 minutes, but it could be useful not to fail the whole test suite but only warn in that case.
By default, plugin manager still wait indefinitely but it can be modified using new `--timeout` option:
```sh
bin/plugin --install elasticsearch/kibana --timeout 30s
bin/plugin --install elasticsearch/kibana --timeout 1h
```
Closes#4603.
Closes#4600.
This adds the field data circuit breaker, which is used to estimate
the amount of memory required to load field data before loading it. It
then raises a CircuitBreakingException if the limit is exceeded.
It is configured with two parameters:
`indices.fielddata.cache.breaker.limit` - the maximum number of bytes
of field data to be loaded before circuit breaking. Defaults to
`indices.fielddata.cache.size` if set, unbounded otherwise.
`indices.fielddata.cache.breaker.overhead` - a contast for all field
data estimations to be multiplied with before aggregation. Defaults to
1.03.
Both settings can be configured dynamically using the cluster update
settings API.
Currently there are two get aliases apis that both have the same functionality, but have a different response structure. The reason for having 2 apis is historic.
The GET _alias api was added in 0.90.x and is more efficient since it only sends the needed alias data from the cluster state between the master node and the node that received the request. In the GET _aliases api the complete cluster state is send to the node that received the request and then the right information is filtered out and send back to the client.
The GET _aliases api should be removed in favour for the alias api
Closes to #4539
* `ignore_unavailable` - Controls whether to ignore if any specified indices are unavailable, this includes indices that don't exist or closed indices. Either `true` or `false` can be specified.
* `allow_no_indices` - Controls whether to fail if a wildcard indices expressions results into no concrete indices. Either `true` or `false` can be specified. For example if the wildcard expression `foo*` is specified and no indices are available that start with `foo` then depending on this setting the request will fail. This setting is also applicable when `_all`, `*` or no index has been specified.
* `expand_wildcards` - Controls to what kind of concrete indices wildcard indices expression expand to. If `open` is specified then the wildcard expression if expanded to only open indices and if `closed` is specified then the wildcard expression if expanded only to closed indices. Also both values (`open,closed`) can be specified to expand to all indices.
Closes to #4436
This commits add doc values support to geo point using the exact same approach
as for numeric data: geo points for a given document are stored uncompressed
and sequentially in a single binary doc values field.
Close#4207
This commit allows to trade precision for memory when storing geo points.
This new field data impl accepts a `precision` parameter that controls the
maximum expected error for storing coordinates. This option can be updated on
a live index with the PUT mapping API.
Default precision is 1cm, which requires 8 bytes per geo-point (50% memory
saving compared to using 2 doubles).
Close#4386
Instead of using the '-f' parameter to start elasticsearch in the
foreground, this is now the default modus.
In order to start elasticsearch in the background, the '-d' parameter
can be used.
Closes#4392
The `text` query was replaced by the `match` query and has been
deprecated for quite a while.
The `field` query should be replaced by a `query_string` query with
the `default_field` specified.
Fixes#4033
This commit changes field data configuration updates so that they are
immediately taken into account for loading new segments. The way it works
is that field data configuration is now cached separately from the field
data cache, meaning that it is now possible to clear the field data
configuration from IndexFieldDataService while the cache will stay around. On
the next time that Elasticsearch will reload field data configuration, it will
check if there is already a cache entry, and reuse it if it exists.
To disable field data loading, all that is required is to change the field
data format to "none" (supported by all field data types) using the update
mapping API. Elasticsearch will then refuse to load field data on any new
segment, but field data which has been loaded on the previous segments will
remain available. So you need to clear the field data cache in order to
reclaim memory (otherwise memory will be reclaimed slower, as segments get
merged).
Close#4430Close#4431
When the ValuesSource has ordinals, terms ordinals are used as a cache key to
bucket ordinals. This can make terms aggregations on String terms significantly
faster.
Close#4350
The percolator uses this option to deal with the fact that the MemoryIndex doesn't support stored fields,
this is possible b/c the _source of the document being percolated is always present.
Closes#4348
This adds support for Lucene's SimpleQueryParser by adding a new type
of query called the `simple_query_string`. The `simple_query_string`
query is designed to be able to parse human-entered queries without
throwing any exceptions.
Resolves#4159
In order to be sure that memory mapped lucene directories are working
one can configure the kernel about how many memory mapped areas
a process may have. This setting ensure for the debian and redhat initscripts
as well as the systemd startup, that this setting is set high enough.
Closes#4397
This contribution is based on the feedback given in issue #4254 and
issue #4255, and should clear things up, when suggestions are being
removed and not displayed anymore after deletion of data.
The Fast Vector Highlighter can combine matches on multiple fields to
highlight a single field using `matched_fields`. This is most
intuitive for multifields that analyze the same string in different
ways. Example:
{
"query": {
"query_string": {
"query": "content.plain:running scissors",
"fields": ["content"]
}
},
"highlight": {
"order": "score",
"fields": {
"content": {
"matched_fields": ["content", "content.plain"],
"type" : "fvh"
}
}
}
}
Closes#3750
* Minor alignments (like setter to ctor)
* FuzzySuggester has a unicode aware flag, which is not exposed in the fuzzy completion request parameters
* Made XAnalyzingSuggester flags (PAYLOAD_SEP, END_BYTE, SEP_LABEL) to be written into the postings format, so we can retain backwards compatibility
* The above change also implies, that these flags can be set per instantiated XAnalyzingSuggester
* CompletionPostingsFormatTest now uses a randomProvider for writing data to check for bwc
Add FieldDataTermsFilter that compares terms out of
the fielddata cache. When filtering on a large
set of terms this filter can be considerably faster
than using a standard lucene terms filter.
Add the "fielddata" execution mode to the
terms filter parser to enable the use of
the new FieldDataTermsFilter.
Add supporting tests and documentation.
Closes#4209
The 'default' / 'standard' analyzer can be a trappy default sicne it filters
english stopwords by default. Yet a default should not be dedicated to a certain language
since elasticsearch is used in many different scenarios where a standard analysis chain
with specialization to english full-text might be rather counter productive.
This commit changes the 'standard' analyzer to use an empty stopword list for indices
that are created from 1.0.0.Beta1 version onwards but will maintain backwards compatibiliy
for older indices.
Closes#3775
Use .percolator as the internal (hidden) type name for percolators within the index. Seems nicer name to represent "hidden" types within an index.
closes#4090
This allows the RegexpQueryBuilder to be used in span queries
Added tests for all span multi term queries.
Also updated the documentation and removed mentioning of numeric range
queries for span queries (they have to be terms).
Closes#3392
This new API allows to get the mapping for a specific set of fields rather than get the whole index mapping and traverse it.
The fields to be retrieved can be specified by their full path, index name and field name and will be resolved in this order.
In case multiple field match, the first one will be returned.
Since we are now generating the output (rather then fall back to the stored mapping), you can specify `include_defaults`=true on the request to have default values returned.
Closes#3941
The setting causes the upper bound for a range query/filter to be rounded up,
therefore the name `round_ceil` seems to make more sense.
Also this commit removes the redundant fourth parameter to DateMathParser.parse(..)
which was never used.
was: parse(String text, long now, boolean roundUp, boolean upperInclusive)
is now: parse(String text, long now, boolean roundCeil)
closes#3914
Requires field index_options set to "offsets" in order to store positions and offsets in the postings list.
Considerably faster than the plain highlighter since it doesn't require to reanalyze the text to be highlighted: the larger the documents the better the performance gain should be.
Requires less disk space than term_vectors, needed for the fast_vector_highlighter.
Breaks the text into sentences and highlights them. Uses a BreakIterator to find sentences in the text. Plays really well with natural text, not quite the same if the text contains html markup for instance.
Treats the document as the whole corpus, and scores individual sentences as if they were documents in this corpus, using the BM25 algorithm.
Uses forked version of lucene postings highlighter to support:
- per value discrete highlighting for fields that have multiple values, needed when number_of_fragments=0 since we want to return a snippet per value
- manually passing in query terms to avoid calling extract terms multiple times, since we use a different highlighter instance per doc/field, but the query is always the same
The lucene postings highlighter api is quite different compared to the existing highlighters api, the main difference being that it allows to highlight multiple fields in multiple docs with a single call, ensuring sequential IO.
The way it is introduced in elasticsearch in this first round is a compromise trying not to change the current highlight api, which works per document, per field. The main disadvantage is that we lose the sequential IO, but we can always refactor the highlight api to work with multiple documents.
Supports pre_tag, post_tag, number_of_fragments (0 highlights the whole field), require_field_match, no_match_size, order by score and html encoding.
Closes#3704
You can configure the highlighting api to return an excerpt of a field
even if there wasn't a match on the field.
The FVH makes excerpts from the beginning of the string to the first
boundary character after the requested length or the boundary_max_scan,
whichever comes first. The Plain highlighter makes excerpts from the
beginning of the string to the end of the last token before the requested
length.
Closes#1171
The description of the timeout parameter was worded misleadingly; it implied that the API would wait until the cluster reached the desired level and then stayed at that level for the timeout. I've tweaked the sentence to remove the risk of confusion.
The suggest stop filter is an improved version of the stop filter, which
takes stopwords only into account if the last char of a query is a
whitespace. This allows you to keep stopwords, but to allow suggesting for
"a".
Example: Index document content "a word". You are now able to suggest for
"a" and get back results in the completion suggester, if the suggest stop
filter is used on the query side, but will not get back any results for
"a " as this is identified as a stopword.
The implementation allows to set the `remove_trailing` parameter for a
custom stop filter and thus use the suggest stop filter instead of the
standard stop filter.
- "boost" should be "boost_factor"
- "mult" should be "multiply"
Also, store combine function names in ImmutableMap instead of iterating
over all possible names each time.
closes#3872 for master
Now that we properly fixed the ability to set the queue size on the index / bulk thread pool, we should actually set them to a somehow reasonable value to protect from users potentially overflowing our system.
I suggest defaults to be 50 for bulk, and 200 for indexing.
Also, set the thread pool for get, which we should set (in a similar value to a "read" queue size we have today).
closes#3888
This commit allows for using Lucene doc values as a backend for field data,
moving the cost of building field data from the refresh operation to indexing.
In addition, Lucene doc values can be stored on disk (partially, or even
entirely), so that memory management is done at the operating system level
(file-system cache) instead of the JVM, avoiding long pauses during major
collections due to large heaps.
So far doc values are supported on numeric types and non-analyzed strings
(index:no or index:not_analyzed). Under the hood, it uses SORTED_SET doc values
which is the only type to support multi-valued fields. Since the field data API
set is a bit wider than the doc values API set, some operations are not
supported:
- field data filtering: this will fail if doc values are enabled,
- field data cache clearing, even for memory-based doc values formats,
- getting the memory usage for a specific field,
- knowing whether a field is actually multi-valued.
This commit also allows for configuring doc-values formats on a per-field basis
similarly to postings formats. In particular the doc values format of the
_version field can be configured through its own field mapper (it used to be
handled in UidFieldMapper previously).
Closes#3806
* Merged segments are now warmed-up at the end of the merge operation instead
of _refresh, so that _refresh doesn't pay the price for the warm-up of merged
segments, which is often higher than flushed segments because of their size.
* Even when no _warmer is registered, some basic warm-up of the segments is
performed: norms, doc values (_version). This should help a bit people who
forget to register warmers.
* Eager loading support for the parent id cache and field data: when one
can't predict what terms will be present in the index, it is tempting to use
a match_all query in a warmer, but in that case, query execution might not be
much faster than field data loading so having a warmer that only loads field
data without running a query can be useful.
Closes#3819