With this commit we rename `node.store.allow_mmapfs` to
`node.store.allow_mmap`. Previously this setting has controlled whether
`mmapfs` could be used as a store type. With the introduction of
`hybridfs` which also relies on memory-mapping,
`node.store.allow_mmapfs` also applies to `hybridfs` and thus we rename
it in order to convey that it is actually used to allow memory-mapping
but not a specific store type.
Relates #36668
Relates #37070
With this commit we introduce a new store type `hybridfs` that is a
hybrid between `mmapfs` and `niofs`. This store type chooses different
strategies to read Lucene files based on the read access pattern (random
or linear) in order to optimize performance.
This store type has been available in earlier versions of Elasticsearch
as `default_fs`. We have chosen a different name now in order to convey
the intent of the store type instead of tying it to the fact whether it
is the default choice.
Relates #36668
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
#32281 adds elasticsearch-shard to provide bwc version of elasticsearch-translog for 6.x; have to remove elasticsearch-translog for 7.0
Relates to #31389
The main benefit of the upgrade for users is the search optimization for top scored documents when the total hit count is not needed. However this optimization is not activated in this change, there is another issue opened to discuss how it should be integrated smoothly.
Some comments about the change:
* Tests that can produce negative scores have been adapted but we need to forbid them completely: #33309Closes#32899
The maximum map count boostrap check can be a hindrance to users that do
not own the underlying platform on which they are executing
Elasticsearch. This is because addressing it requires tuning the kernel
and a platform provider might now allow this, especially on shared
infrastructure. However, this bootstrap check is not needed if mmapfs is
not in use. Today we do not have a way for the user to communicate that
they are not going to use mmapfs. This commit therefore adds a setting
that enables the user to disallow mmapfs. When mmapfs is disallowed, the
maximum map count bootstrap check is not enforced. Additionally, we
fallback to a different default index store and prevent the explicit use
of mmapfs for an index.
First, some background: we have 15 different methods to get a logger in
Elasticsearch but they can be broken down into three broad categories
based on what information is provided when building the logger.
Just a class like:
```
private static final Logger logger = ESLoggerFactory.getLogger(ActionModule.class);
```
or:
```
protected final Logger logger = Loggers.getLogger(getClass());
```
The class and settings:
```
this.logger = Loggers.getLogger(getClass(), settings);
```
Or more information like:
```
Loggers.getLogger("index.store.deletes", settings, shardId)
```
The goal of the "class and settings" variant is to attach the node name
to the logger. Because we don't always have the settings available, we
often use the "just a class" variant and get loggers without node names
attached. There isn't any real consistency here. Some loggers get the
node name because it is convenient and some do not.
This change makes the node name available to all loggers all the time.
Almost. There are some caveats are testing that I'll get to. But in
*production* code the node name is node available to all loggers. This
means we can stop using the "class and settings" variants to fetch
loggers which was the real goal here, but a pleasant side effect is that
the ndoe name is now consitent on every log line and optional by editing
the logging pattern. This is all powered by setting the node name
statically on a logging formatter very early in initialization.
Now to tests: tests can't set the node name statically because
subclasses of `ESIntegTestCase` run many nodes in the same jvm, even in
the same class loader. Also, lots of tests don't run with a real node so
they don't *have* a node name at all. To support multiple nodes in the
same JVM tests suss out the node name from the thread name which works
surprisingly well and easy to test in a nice way. For those threads
that are not part of an `ESIntegTestCase` node we stick whatever useful
information we can get form the thread name in the place of the node
name. This allows us to keep the logger format consistent.
We removed the default_fs store type yet the docs still contain a
reference to them. This commit addresses that by removing this
reference, and changing a reference to this section of the docs to
instead refer to mmapfs.
This improves the way similarities are plugged in in order to:
- reject the classic similarity on 7.x indices and emit a deprecation
warning otherwise
- reject unkwown parameters on 7.x indices and emit a deprecation
warning otherwise
Even though this breaks the plugin API, I'd like to backport to 7.x so
that users can get deprecation warnings when they are doing something
that will become unsupported in the future.
Closes#23208Closes#29035
The use of the phrase "translog" vs "transaction log" was inconsistent, and
it was apparently unclear that the translog was stored on every shard copy.
Allowing `_doc` as a type will enable users to make the transition to 7.0
smoother since the index APIs will be `PUT index/_doc/id` and `POST index/_doc`.
This also moves most of the documentation to `_doc` as a type name.
Closes#27750Closes#27751
The existing log rotation configuration allowed the index
and search slow log to grow unbounded. This commit removes the
date based rotation and adds the same size based rotation, that
the depreciation log already has.
Early termination with index sorting always return the best top N in the response but set the flag `terminated_early`
in the response. This can be confusing because we use the same flag for `terminate_after` which on the contrary returns partial results.
This change removes the flag when results are not partial (early termination due to index sorting) and keeps it only when `terminate_after` is used.
Closes#26408
The goal of this similarity is to help users who would like to keep the
functionality of the `tf-idf` similarity that we want to remove, or to allow
for specific usec-cases (disabling idf, disabling tf, disabling length norm,
etc.) to not have to build a custom plugin and familiarize with the low-level
Lucene API.
#25147 added the translog deletion policy but didn't enable it by default. This PR enables a default retention of 512MB (same maximum size of the current translog) and an age of 12 hours (i.e., after 12 hours all translog files will be deleted). This increases to chance to have an ops based recovery, even if the primary flushed or the replica was offline for a few hours.
In order to see which parts of the translog are committed into lucene the translog stats are extended to include information about uncommitted operations.
Views now include all translog ops and guarantee, as before, that those will not go away. Snapshotting a view allows to filter out generations that are not relevant based on a specific sequence number.
Relates to #10708
This commit refactors the query phase in order to be able
to automatically detect queries that can be early terminated.
If the index sort matches the query sort, the top docs collection is early terminated
on each segment and the computing of the total number of hits that match the query is delegated to a simple TotalHitCountCollector.
This change also adds a new parameter to the search request called `track_total_hits`.
It indicates if the total number of hits that match the query should be tracked.
If false, queries sorted by the index sort will not try to compute this information and
and will limit the collection to the first N documents per segment.
Aggregations are not impacted and will continue to see every document
even when the index sort matches the query sort and `track_total_hits` is false.
Relates #6720
This change adds an index setting to define how the documents should be sorted inside each Segment.
It allows any numeric, date, boolean or keyword field inside a mapping to be used to sort the index on disk.
It is not allowed to use a `nested` fields inside an index that defines an index sorting since `nested` fields relies on the original sort of the index.
This change does not add early termination capabilities in the search layer. This will be added in a follow up.
Relates #6720
We want to upgrade to Lucene 7 ahead of time in order to be able to check whether it causes any trouble to Elasticsearch before Lucene 7.0 gets released. From a user perspective, the main benefit of this upgrade is the enhanced support for sparse fields, whose resource consumption is now function of the number of docs that have a value rather than the total number of docs in the index.
Some notes about the change:
- it includes the deprecation of the `disable_coord` parameter of the `bool` and `common_terms` queries: Lucene has removed support for coord factors
- it includes the deprecation of the `index.similarity.base` expert setting, since it was only useful to configure coords and query norms, which have both been removed
- two tests have been marked with `@AwaitsFix` because of #23966, which we intend to address after the merge
In 5.0, the search slow log switched to the multi-line format with no option to get back to the origin single-line format that was used prior to 5.0 by default. This commit removes the reformat option from the search slow log and returns the search slow log back to the single-line format.
Closes#21711
* Add docs with up to date instructions on updating default similarity
The default similarity can no longer be set in the configuration file
(you will get an error on startup). Update the docs with the method
that works.
* Add instructions for changing similarity on index creation
This commit fixes two issues with the slow log docs:
- clarifies that these settings are per index
- updates index slow log configuration for Log4j 2
Relates #20976
The default similarity was set to `classic` which refers to TFIDF and has not been moved after the upgrade to Lucene 6.
Though moving to BM25 could have some downside for queries that relies on coordination factor (match_query, multi_match_query) ?
relates #18944
The MMapDirectory has a switch that allows the content of files to be loaded
into the filesystem cache upon opening. This commit exposes it with the new
`index.store.pre_load` setting.
The syntax highlighter only supports [source,js].
Also adds a check to the rest test generator that runs during
the build that'll fail the build if it sees `[source,json]`.
Today when parsing settings during bootstrap, we add a system property
for every Elasticsearch setting. Additionally, settings can be set via
system properties. This commit simplifies this situation.
- settings are no longer propogated to system properties
- system properties can not be used to set settings
- the "es." prefix on settings is no longer required (nor permitted)
- test logging has a dedicated system property (tests.logger.level)
Relates #18198
Josh Soref
Daniel Mitterdorfer
debadair
Jim Ferenczi
Vladimir Dolzhenko
Jason Tedor
Nik Everett
Adrien Grand
srini-raman
Sue Gallagher
David Turner
Christoph Büscher
Alexander Reelsen
agent5566
Tanguy Leroux
Clinton Gormley
Boaz Leskes
Igor Motov
Loek van Gool
Adriel Dean-Hall
Pascal Borreli
Lee Hinman
Sakthipriyan Vairamani
eratio08
trangvh