With #37566 we have introduced the ability to merge multiple search responses into one. That makes it possible to expose a new way of executing cross-cluster search requests, that makes CCS much faster whenever there is network latency between the CCS coordinating node and the remote clusters. The coordinating node can now send a single search request to each remote cluster, which gets reduced by each one of them. from + size results are requested to each cluster, and the reduce phase in each cluster is non final (meaning that buckets are not pruned and pipeline aggs are not executed). The CCS coordinating node performs an additional, final reduction, which produces one search response out of the multiple responses received from the different clusters.
This new execution path will be activated by default for any CCS request unless a scroll is provided or inner hits are requested as part of field collapsing. The search API accepts now a new parameter called ccs_minimize_roundtrips that allows to opt-out of the default behaviour.
Relates to #32125
Users may require the sequence number and primary terms to perform optimistic concurrency control operations. Currently, you can get the sequence number via the `docvalues_fields` API but the primary term is not accessible because it is maintained by the `SeqNoFieldMapper` and the infrastructure can't find it.
This commit adds a dedicated sub fetch phase to return both numbers that is connected to a new `seq_no_primary_term` parameter.
This commit changes the format of the `hits.total` in the search response to be an object with
a `value` and a `relation`. The `value` indicates the number of hits that match the query and the
`relation` indicates whether the number is accurate (in which case the relation is equals to `eq`)
or a lower bound of the total (in which case it is equals to `gte`).
This change also adds a parameter called `rest_total_hits_as_int` that can be used in the
search APIs to opt out from this change (retrieve the total hits as a number in the rest response).
Note that currently all search responses are accurate (`track_total_hits: true`) or they don't contain
`hits.total` (`track_total_hits: true`). We'll add a way to get a lower bound of the total hits in a
follow up (to allow numbers to be passed to `track_total_hits`).
Relates #33028
With features like CCR building on the CCS infrastructure, the settings
prefix search.remote makes less sense as the namespace for these remote
cluster settings than does a more general namespace like
cluster.remote. This commit replaces these settings with cluster.remote
with a fallback to the deprecated settings search.remote.
In case an error is returned when calling search_shards on a remote
cluster, which will lead to throwing an exception in the coordinating
node, we should make sure that the status code returned by the
coordinating node is the same as the one returned by the remote
cluster. Up until now a 500 - Internal Server Error was always
returned. This commit changes this behaviour so that for instance if an
index is not found, which causes an 404, a 404 is also returned by the
coordinating node to the client.
Closes#27461
This commit changes the default out-of-the-box configuration for the
number of shards from five to one. We think this will help address a
common problem of oversharding. For users with time-based indices that
need a different default, this can be managed with index templates. For
users with non-time-based indices that find they need to re-shard with
the split API in place they no longer need to resort only to
reindexing.
Since this has the impact of changing the default number of shards used
in REST tests, we want to ensure that we still have coverage for issues
that could arise from multiple shards. As such, we randomize (rarely)
the default number of shards in REST tests to two. This is managed via a
global index template. However, some tests check the templates that are
in the cluster state during the test. Since this template is randomly
there, we need a way for tests to skip adding the template used to set
the number of shards to two. For this we add the default_shards feature
skip. To avoid having to write our docs in a complicated way because
sometimes they might be behind one shard, and sometimes they might be
behind two shards we apply the default_shards feature skip to all docs
tests. That is, these tests will always run with the default number of
shards (one).
Many tests are added with a version check so that they do not run against a
version that doesn't have the feature yet. Master is 7.0, so all tests that
do not run against 6.0+ can be removed and the version check can be removed
on all tests that always run on 6.0+.
Applying the rest test gradle plugin already uses the zip distribution
by default, so specifying it explicitly is not necessary. These are
leftovers from before zip was the default for rest tests.
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.
* REST: Rename ingest.processor.grok to ingest.processor_grok
* REST: Rename remote.info to cluster.remote_info
* REST: Fixed bad YAML comments
* REST: Force dummy scripts to be strings, not numbers
* REST: Fix bad YAML in search/110_field_collapsing.yml
* REST: Adjust percentile tests to work with Perl number handling
The single shard optimization that we have in our search api changes the type of response returned by the query transport action name based on the shard search request. if the request goes to one shard, we will do query and fetch at the same time, hence the response will be different. The proxying layer used in cross cluster search was not aware of this distinction, which causes serialization issues every time a cross cluster search request goes to a single shard and goes through a gateway node which has to forward the shard request to a data node. The coordinating node would then expect a QueryFetchSearchResult while the gateway would return a QuerySearchResult.
Closes#26833
Today when we aggregate on the `_index` field the cross cluster search
alias is not taken into account. Neither is it respected when we search
on the field. This change adds support for cluster alias when the cluster
alias is present on the `_index` field.
Closes#25606
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.
We lost the cluster alias due to some special caseing in inner hits
and due to the fact that we didn't pass on the alias to the shard request.
This change ensures that we have the cluster alias present on the shard to
ensure all SearchShardTarget reads preserve the alias.
Relates to #25606
This commit changes how we determine if there were any remote indices that a search should have
been executed against. Previously, we used the list of remote shard iterators but if the remote
index pattern resolved to no indices there would be no remote shard iterators even though the
request specified remote indices. The map of remote cluster names to the original indices is used
instead so that we can determine if there were remote indices even when there are no remote shard
iterators.
Closes#25426
Today the `_field_caps` API doesn't implement its request serialization
correctly since indices and indices options are not serialized at all.
This will likely break with all transport clients etc. and if this request
must be send across the network. This commit fixes this and adds correct
handling if we have only remote indices to prevent the inclusion of
all local indices.
This commit renames all rest test files to use the .yml extension
instead of .yaml. This way the extension used within all of
elasticsearch for yaml is consistent.
This change simplifies how the rest test runner finds test files and
removes all leniency. Previously multiple prefixes and suffixes would
be tried, and tests could exist inside or outside of the classpath,
although outside of the classpath never quite worked. Now only classpath
tests are supported, and only one resource prefix is supported,
`/rest-api-spec/tests`.
closes#20240
After splitting integ tests into cluster configuration and the test
runner task, we still have dependencies of the test runner added as deps
of the cluster. This commit adds dependencies directly to the cluster,
so that the runner can have other dependencies independent of what is
needed for the cluster.
This is related to #23893. This commit allows users to use wilcards for
cluster names when executing a cross cluster search.
So instead of defining every cluster such as:
GET one:*,two:*,three:*/_search
A user could just search:
GET *:*/_search
As ":" characters are currently allowed in index names, if the text
up to the first ":" does not match a defined cluster name, the entire
string is treated as an index name.
All our actions that are invoked from rest actions have corresponding
transport actions. This adds the transport action for RestRemoteClusterInfoAction
for consistency.
Relates to #23969
Throw error when skip or do sections are malformed, such as they don't start with the proper token (START_OBJECT). That signals bad indentation, which would be ignored otherwise. Thanks (or due to) our pull parsing code, we were still able to properly parse the sections, yet other runners weren't able to.
Closes#21980
* [TEST] fix indentation in matrix_stats yaml tests
* [TEST] fix indentation in painless yaml test
* [TEST] fix indentation in analysis yaml tests
* [TEST] fix indentation in generated docs yaml tests
* [TEST] fix indentation in multi_cluster_search yaml tests
Gradle's finalizedBy on tasks only ensures one task runs after another,
but not immediately after. This is problematic for our integration tests
since it allows multiple project's integ test clusters to be
simultaneously. While this has not been a problem thus far (gradle 2.13
happened to keep the finalizedBy tasks close enough that no clusters
were running in parallel), with gradle 3.3 the task graph generation has
changed, and numerous clusters may be running simultaneously, causing
memory pressure, and thus generally slower tests, or even failure if the
system has a limited amount of memory (eg in a vagrant host).
This commit reworks how integ tests are configured. It adds an
`integTestCluster` extension to gradle which is equivalent to the current
`integTest.cluster` and moves the rest test runner task to
`integTestRunner`. The `integTest` task is then just a dummy task,
which depends on the cluster runner task, as well as the cluster stop
task. This means running `integTest` in one project will both run the
rest tests, and shut down the cluster, before running `integTest` in
another project.
Today either all nodes in the cluster connect to remote clusters of only nodes
that have remote clusters configured in their node config. To allow global remote
cluster configuration but restrict connections to a set of nodes in the cluster
this change adds a new setting `search.remote.connect` (defaults to `true`) to allow
to disable remote cluster connections on a per node basis.
Instead of `search.remote.seeds.${clustername}` we now specify the seeds as:
`search.remote.${clustername}.seeds` which is a real list setting compared to an unvalidated
group setting before.
this commit adds full support for proxy nodes on the search layer.
This allows to connection only to a small set of nodes on a remote cluster
to exectue the search. The nodes will proxy the request to the correct node in the
cluster while the coordinting node doesn't need to be connected to the target node.
This commit adds `qa/multi-cluster-search` which currently does a
simple search across 2 clusters. This commit also adds support for IPv6
addresses and fixes an issue where all shards of the local cluster are searched
when only a remote index was given.
Luca Cavanna
Boaz Leskes
Alpar Torok
Jim Ferenczi
Jason Tedor
Adrien Grand
Nik Everett
Ryan Ernst
javanna
Clinton Gormley
Simon Willnauer
Jay Modi
Tim Brooks