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
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.
Today, certain bootstrap properties are set and read via system
properties. This action-at-distance way of managing these properties is
rather confusing, and completely unnecessary. But another problem exists
with setting these as system properties. Namely, these system properties
are interpreted as Elasticsearch settings, not all of which are
registered. This leads to Elasticsearch failing to startup if any of
these special properties are set. Instead, these properties should be
kept as local as possible, and passed around as method parameters where
needed. This eliminates the action-at-distance way of handling these
properties, and eliminates the need to register these non-setting
properties. This commit does exactly that.
Additionally, today we use the "-D" command line flag to set the
properties, but this is confusing because "-D" is a special flag to the
JVM for setting system properties. This creates confusion because some
"-D" properties should be passed via arguments to the JVM (so via
ES_JAVA_OPTS), and some should be passed as arguments to
Elasticsearch. This commit changes the "-D" flag for Elasticsearch
settings to "-E".
This commit limits the `index.translog.sync_interval` to a value not less than `100ms` and
removes the support for fsync on every operation which used to be enabled if `index.translog.sync_interval` was set to `0s`
Now this pr also only schedules an async fsync if the durability is set to `async`. By default not async task is scheduled.
Closes#16152
Today we have two variants of translogs for indexing. We only recommend the buffered
one which also has a 20% advantage in indexing speed. This commit removes the option and defaults
to the buffered case. It also hard-wires the translog buffer to 8kb instead of 64kb. We used to
adjust that buffer based on if the shard is active or not, this code has also been removed and
instead we just keep an 8kb buffer arround.
This commit removes `index.translog.flush_threshold_ops` and `index.translog.disable_flush`
in favor of `index.translog.flush_threshold_size`. The number of operations is meaningless by itself and
can easily be turned into a size value with knowledge of the data. Disabling the flush is only useful in
tests and we can set the size value to a really high value. If users really need to do this they can
also apply a very high value like `1PB`.
- moves calculation of the delay to a single place (ReplicaShardAllocator)
- reduces coupling between GatewayAllocator and RoutingService
- in master failover situations, elapsed delay time is forgotten
Closes#14808
This adds the `cluster.routing.allocation.total_shards_per_node`
setting, which limits the total number of shards across all indices on
each node. It defaults to -1 and can be dynamically configured.
Resolves#14456
This commit moves the size and ops based flush into a synchronous API into
IndexShard and removes the time-based flush alltogether since it' basically
covered by the inactive async flush API we have today. The functionality doesn't
need to be covered by scheduled task and async APIs while we can actually make all
the decisions in a sync manner which is way easier to control and to test.
Closes#13707
Allocation filtering by IP only works today using the node host address. But in some cases, you might want to filter using the publish address which could be different.
Instead of logging the entire `_source` in the indexing slowlog we log by
default just the first 1000 characters - this is controlled by the
`index.indexing.slowlog.source` settings and can be set to `true` to log the
whole `_source`, `false` to log none of it, and a number to log at most that
many characters.
Closes#4485
Change the default delayed allocation timeout from 0 (no delayed allocation) to 1m. The value came from a test of having a node with 50 shards being indexed into (so beefy translog requiring flush on shutdown), then shutting it down and starting it back up and waiting for it to join the cluster. This took, on a slow machine, about 30s.
The value is conservatively low and does not try to address a virtual machine / OS restart for now, in order to not have the affect of node going away and users being concerned that shards are not being allocated to the rest of the cluster as a result of that. The setting can always be changed in order to increase the delayed allocation if needed.
closes#12166
Now that doc values are the default for fielddata, specialized in-memory
formats are becoming an esoteric option. This commit removes such formats:
- `fst` on string fields,
- `compressed` on geo points.
I also removed documentation and tests that the fielddata cache is shared if
you change the format, since this is only true for in-memory fielddata formats
(given that for doc values, the caching is done directly in Lucene).
Today we provide the ability to plug in MergePolicy and
we provide the once lucene ships with. We do not recommend to change
the default and even only a small number of expert users would ever touch
this. This commit removes the ancient log byte size and log doc count
merge policy providers, simplifies the MergePolicy wiring and makes the
tiered MP the one and only default. All notions of a merge policy has been
removed from the docs and should be deprecated in the previous version.
Closes#11588
Using files that must be specified on each node is an anti-pattern
from the API based goal of ES. This change removes the ability
to specify the default mapping with a file on each node.
closes#10620
In order to safely complete recoveries / relocations we have to keep all operation done since the recovery start at available for replay. At the moment we do so by preventing the engine from flushing and thus making sure that the operations are kept in the translog. A side effect of this is that the translog keeps on growing until the recovery is done. This is not a problem as we do need these operations but if the another recovery starts concurrently it may have an unneededly long translog to replay. Also, if we shutdown the engine for some reason at this point (like when a node is restarted) we have to recover a long translog when we come back.
To void this, the translog is changed to be based on multiple files instead of a single one. This allows recoveries to keep hold to the files they need while allowing the engine to flush and do a lucene commit (which will create a new translog files bellow the hood).
Change highlights:
- Refactor Translog file management to allow for multiple files.
- Translog maintains a list of referenced files, both by outstanding recoveries and files containing operations not yet committed to Lucene.
- A new Translog.View concept is introduced, allowing recoveries to get a reference to all currently uncommitted translog files plus all future translog files created until the view is closed. They can use this view to iterate over operations.
- Recovery phase3 is removed. That phase was replaying operations while preventing new writes to the engine. This is unneeded as standard indexing also send all operations from the start of the recovery to the recovering shard. Replay all ops in the view acquired in recovery start is enough to guarantee no operation is lost.
- IndexShard now creates the translog together with the engine. The translog is closed by the engine on close. ShadowIndexShards do not open the translog.
- Moved the ownership of translog fsyncing to the translog it self, changing the responsible setting to `index.translog.sync_interval` (was `index.gateway.local.sync`)
Closes#10624
* Removed the docs for `index.compound_format` and `index.compound_on_flush` - these are expert settings which should probably be removed (see https://github.com/elastic/elasticsearch/issues/10778)
* Removed the docs for `index.index_concurrency` - another expert setting
* Labelled the segments verbose output as experimental
* Marked the `compression`, `precision_threshold` and `rehash` options as experimental in the cardinality and percentile aggs
* Improved the experimental text on `significant_terms`, `execution_hint` in the terms agg, and `terminate_after` param on count and search
* Removed the experimental flag on the `geobounds` agg
* Marked the settings in the `merge` and `store` modules as experimental, rather than the modules themselves
Closes#10782
This commit brings the benefits of the `count` search type to search requests
that have a `size` of 0:
- a single round-trip to shards (no fetch phase)
- ability to use the query cache
Since `count` now provides no benefits over `query_then_fetch`, it has been
deprecated.
Close#7630
We now have a very useful annotation to mark features or parameters as
experimental. Let's use it! This commit replaces some custom text warnings with
this annotation and adds this annotation to some existing features/parameters:
- inner_hits (unreleased yet)
- terminate_after (released in 1.4)
- per-bucket doc count errors in the terms agg (released in 1.4)
I also tagged with this annotation settings which should either be not needed
(like the ability to evict entries from the filter cache based on time) or that
are too deep into the way that Elasticsearch works like the Directory
implementation or merge settings.
Close#9563
This particular note was about fielddata filtering but could cause confusion
that fields that have doc values enabled cannot be used for filtering (as in
a `filtered_query`).
When using the DiskThresholdDecider, it's possible that shards could
already be marked as relocating to the node being evaluated. This commit
adds a new setting `cluster.routing.allocation.disk.include_relocations`
which adds the size of the shards currently being relocated to this node
to the node's used disk space.
This new option defaults to `true`, however it's possible to
over-estimate the usage for a node if the relocation is already
partially complete, for instance:
A node with a 10gb shard that's 45% of the way through a relocation
would add 10gb + (.45 * 10) = 14.5gb to the node's disk usage before
examining the watermarks to see if a new shard can be allocated.
Fixes#7753
Relates to #6168
This documentation was dangerous because it felt like it was possible to gain
substantial performance by just switching the codec of the index.
However, non-default codecs are dangerous to use since they are not supported
in terms of backward compatibility, and most improvements that they bring have
been folded into the default codec anyway (for example, the default codec
"pulses" postings lists that contain a single document).
Tanguy Leroux
Adrien Grand
Clinton Gormley
Boaz Leskes
Deb Adair
Jim Ferenczi
Igor Motov
Loek van Gool
Adriel Dean-Hall
Jason Tedor
Pascal Borreli
Lee Hinman
Sakthipriyan Vairamani
eratio08
trangvh
Nik Everett
Simon Willnauer
Dongjoon Hyun
Robert Muir
William
Yannick Welsch
Jason O'Donnell
David Pilato
Michael McCandless
Shay Banon
Martijn van Groningen
Ryan Ernst
Joshua Rich
Masaru Hasegawa
Itamar Syn-Hershko
Israel Tsadok
Henrik Nordvik
Suyog Rao
Tanvir Alam
Alexander Reelsen