Today Cross Cluster Search requires at least one node in each remote cluster to be up once the cross cluster search is run. Otherwise the whole search request fails despite some of the data (either local and/or remote) is available. This happens when performing the _search/shards calls to find out which remote shards the query has to be executed on. This scenario is different from shard failures that may happen later on when the query is actually executed, in case e.g. remote shards are missing, which is not going to fail the whole request but rather yield partial results, and the _shards section in the response will indicate that.
This commit introduces a boolean setting per cluster called search.remote.$cluster_alias.skip_if_disconnected, set to false by default, which allows to skip certain clusters if they are down when trying to reach them through a cross cluster search requests. By default all clusters are mandatory.
Scroll requests support such setting too when they are first initiated (first search request with scroll parameter), but subsequent scroll rounds (_search/scroll endpoint) will fail if some of the remote clusters went down meanwhile.
The search API response contains now a new _clusters section, similar to the _shards section, that gets returned whenever one or more clusters were disconnected and got skipped:
"_clusters" : {
"total" : 3,
"successful" : 2,
"skipped" : 1
}
Such section won't be part of the response if no clusters have been skipped.
The per cluster skip_unavailable setting value has also been added to the output of the remote/info API.
The shard preference _primary, _replica and its variants were useful
for the asynchronous replication. However, with the current impl, they
are no longer useful and should be removed.
Closes#26335
This allows plugins to plug rescore implementations into
Elasticsearch. While this is a fairly expert thing to do I've
done my best to point folks to the QueryRescorer as one that at
least documents the tradeoffs that it makes. I've attempted to
limit the API surface area by removing `SearchContext` from the
exposed interface, instead exposing just the IndexSearcher and
`QueryShardContext`. I also tried to make some of the class names
more consistent and do some general cleanup while I was there.
I entertained the notion of moving the `QueryRescorer` to module.
After all, it'd be a wonderful test to prove that you can plug
rescore implementation into Elasticsearch if the only built in
rescore implementation is in the module. But I decided against it
because the new module would require a client jar and it'd require
moving some more things around. I think if we really want to do
it, we should do it as a followup.
I did, on the other hand, create an "example" rescore plugin which
should both be a nice example for anyone wanting to plug in their
own rescore implementation and servers as a good integration test
to make sure that you can indeed plug one in.
Closes#26208
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.
Removes the `assemble` task from the `build` task when we have
removed `assemble` from the project. We removed `assemble` from
projects that aren't published so our releases will be faster. But
That broke CI because CI builds with `gradle precommit build` and,
it turns out, that `build` includes `check` and `assemble`. With
this change CI will only run `check` for projects without an
`assemble`.
Removes the `assemble` task from projects that are not published.
This should speed up `gradle assemble` by skipping projects that
don't need to be built. Which is useful because `gradle assemble`
is how we cut releases.
REST handlers that require a body will throw an an ElasticsearchParseException "request body required".
REST handlers that require a body OR source param will throw an ElasticsearchParseException "request body or source param required".
Replaced asserts in BulkRequest parsing code with a more descriptive IllegalArgumentException if the line contains an empty object.
Updated bulk REST test to verify an empty action line is rejected properly.
Updated BulkRequestTests with randomized testing for an empty action line.
Used try-with-resouces for XContentParser in AbstractBulkByQueryRestHandler.
* Adds nodes usage API to monitor usages of actions
The nodes usage API has 2 main endpoints
/_nodes/usage and /_nodes/{nodeIds}/usage return the usage statistics
for all nodes and the specified node(s) respectively.
At the moment only one type of usage statistics is available, the REST
actions usage. This records the number of times each REST action class is
called and when the nodes usage api is called will return a map of rest
action class name to long representing the number of times each of the action
classes has been called.
Still to do:
* [x] Create usage service to store usage statistics
* [x] Record usage in REST layer
* [x] Add Transport Actions
* [x] Add REST Actions
* [x] Tests
* [x] Documentation
* Rafactors UsageService so counts are done by the handlers
* Fixing up docs tests
* Adds a name to all rest actions
* Addresses review comments
In #23253 we added an the ability to incrementally reduce search results.
This change exposes the parameter to control the batch since and therefore
the memory consumption of a large search request.
We have a bunch of interfaces that have only a single implementation
for 6 years now. These interfaces are pretty useless from a SW development
perspective and only add unnecessary abstractions. They also require
lots of casting in many places where we expect that there is only one
concrete implementation. This change removes the interfaces, makes
all of the classes final and removes the duplicate `foo` `getFoo` accessors
in favor of `getFoo` from these classes.
This commit upgrades the checkstyle configuration from version 5.9 to
version 7.5, the latest version as of today. The main enhancement
obtained via this upgrade is better detection of redundant modifiers.
Relates #22960
This change adds a strict mode for xcontent parsing on the rest layer. The strict mode will be off by default for 5.x and in a separate commit will be enabled by default for 6.0. The strict mode, which can be enabled by setting `http.content_type.required: true` in 5.x, will require that all incoming rest requests have a valid and supported content type header before the request is dispatched. In the non-strict mode, the Content-Type header will be inspected and if it is not present or not valid, we will continue with auto detection of content like we have done previously.
The content type header is parsed to the matching XContentType value with the only exception being for plain text requests. This value is then passed on with the content bytes so that we can reduce the number of places where we need to auto-detect the content type.
As part of this, many transport requests and builders were updated to provide methods that
accepted the XContentType along with the bytes and the methods that would rely on auto-detection have been deprecated.
In the non-strict mode, deprecation warnings are issued whenever a request with body doesn't provide the Content-Type header.
See #19388
There are presently 7 ctor args used in any rest handlers:
* `Settings`: Every handler uses it to initialize a logger and
some other strange things.
* `RestController`: Every handler registers itself with it.
* `ClusterSettings`: Used by `RestClusterGetSettingsAction` to
render the default values for cluster settings.
* `IndexScopedSettings`: Used by `RestGetSettingsAction` to get
the default values for index settings.
* `SettingsFilter`: Used by a few handlers to filter returned
settings so we don't expose stuff like passwords.
* `IndexNameExpressionResolver`: Used by `_cat/indices` to
filter the list of indices.
* `Supplier<DiscoveryNodes>`: Used to fill enrich the response
by handlers that list tasks.
We probably want to reduce these arguments over time but
switching construction away from guice gives us tighter
control over the list of available arguments.
These parameters are passed to plugins using
`ActionPlugin#initRestHandlers` which is expected to build and
return that handlers immediately. This felt simpler than
returning an reference to the ctors given all the different
possible args.
Breaks java plugins by moving rest handlers off of guice.
Today when parsing a request, Elasticsearch silently ignores incorrect
(including parameters with typos) or unused parameters. This is bad as
it leads to requests having unintended behavior (e.g., if a user hits
the _analyze API and misspell the "tokenizer" then Elasticsearch will
just use the standard analyzer, completely against intentions).
This commit removes lenient URL parameter parsing. The strategy is
simple: when a request is handled and a parameter is touched, we mark it
as such. Before the request is actually executed, we check to ensure
that all parameters have been consumed. If there are remaining
parameters yet to be consumed, we fail the request with a list of the
unconsumed parameters. An exception has to be made for parameters that
format the response (as opposed to controlling the request); for this
case, handlers are able to provide a list of parameters that should be
excluded from tripping the unconsumed parameters check because those
parameters will be used in formatting the response.
Additionally, some inconsistencies between the parameters in the code
and in the docs are corrected.
Relates #20722
* Build: Remove old maven deploy support
This change removes the old maven deploy that we have in parallel to
maven-publish, and makes maven-publish fully work with publishing to
maven local. Using `gradle publishToMavenLocal` should be used to
publish to .m2.
Note that there is an unfortunate hack that means for
zip artifacts we must first create/publish a dummy pom file, and then
follow that with the real pom file. It would be nice to have the pom
file contains packaging=zip, but maven central then requires sources and
javadocs. But our zips are really just attached artifacts, so we already
set the packaging type to pom for our zip files. This change just works
around a limitation of the underlying maven publishing library which
silently skips attached artifacts when the packaging type is set to pom.
relates #20164closes#20375
* Remove unnecessary extra spacing
This change replaces the fields parameter with stored_fields when it makes sense.
This is dictated by the renaming we made in #18943 for the search API.
The following list of endpoint has been changed to use `stored_fields` instead of `fields`:
* get
* mget
* explain
The documentation and the rest API spec has been updated to cope with the changes for the following APIs:
* delete_by_query
* get
* mget
* explain
The `fields` parameter has been deprecated for the following APIs (it is replaced by _source filtering):
* update: the fields are extracted from the _source directly.
* bulk: the fields parameter is used but fields are extracted from the source directly so it is allowed to have non-stored fields.
Some APIs still have the `fields` parameter for various reasons:
* cat.fielddata: the fields paramaters relates to the fielddata fields that should be printed.
* indices.clear_cache: used to indicate which fielddata fields should be cleared.
* indices.get_field_mapping: used to filter fields in the mapping.
* indices.stats: get stats on fields (stored or not stored).
* termvectors: fields are retrieved from the stored fields if possible and extracted from the _source otherwise.
* mtermvectors:
* nodes.stats: the fields parameter is used to concatenate completion_fields and fielddata_fields so it's not related to stored_fields at all.
Fixes#20155
Luca Cavanna
Nhat
Tal Levy
Nik Everett
Simon Willnauer
Alex Benusovich
Colin Goodheart-Smithe
Jason Tedor
Jay Modi
javanna
Ryan Ernst
Areek Zillur
Jim Ferenczi
Daniel Mitterdorfer
Daniel Mitterdorfer