- Elasticsearch Guide: other versions:
- What is Elasticsearch?
- What’s new in 7.10
- Getting started with Elasticsearch
- Set up Elasticsearch
- Installing Elasticsearch
- Configuring Elasticsearch
- Setting JVM options
- Secure settings
- Auditing settings
- Circuit breaker settings
- Cluster-level shard allocation and routing settings
- Cross-cluster replication settings
- Discovery and cluster formation settings
- Field data cache settings
- HTTP
- Index lifecycle management settings
- Index management settings
- Index recovery settings
- Indexing buffer settings
- License settings
- Local gateway settings
- Logging
- Machine learning settings
- Monitoring settings
- Node
- Network settings
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- Snapshot lifecycle management settings
- Transforms settings
- Transport
- Thread pools
- Watcher settings
- Important Elasticsearch configuration
- Important System Configuration
- Bootstrap Checks
- Heap size check
- File descriptor check
- Memory lock check
- Maximum number of threads check
- Max file size check
- Maximum size virtual memory check
- Maximum map count check
- Client JVM check
- Use serial collector check
- System call filter check
- OnError and OnOutOfMemoryError checks
- Early-access check
- G1GC check
- All permission check
- Discovery configuration check
- Bootstrap Checks for X-Pack
- Starting Elasticsearch
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- Discovery and cluster formation
- Add and remove nodes in your cluster
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- Remote clusters
- Set up X-Pack
- Configuring X-Pack Java Clients
- Plugins
- Upgrade Elasticsearch
- Index modules
- Mapping
- Text analysis
- Overview
- Concepts
- Configure text analysis
- Built-in analyzer reference
- Tokenizer reference
- Token filter reference
- Apostrophe
- ASCII folding
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- Classic
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- Conditional
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- KStem
- Length
- Limit token count
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- Multiplexer
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- Pattern capture
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- Phonetic
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- Remove duplicates
- Reverse
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- Stemmer override
- Stop
- Synonym
- Synonym graph
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- Unique
- Uppercase
- Word delimiter
- Word delimiter graph
- Character filters reference
- Normalizers
- Index templates
- Data streams
- Ingest node
- Search your data
- Query DSL
- Aggregations
- Bucket aggregations
- Adjacency matrix
- Auto-interval date histogram
- Children
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- Date histogram
- Date range
- Diversified sampler
- Filter
- Filters
- Geo-distance
- Geohash grid
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- Global
- Histogram
- IP range
- Missing
- Nested
- Parent
- Range
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- Reverse nested
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- Significant text
- Terms
- Variable width histogram
- Subtleties of bucketing range fields
- Metrics aggregations
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- Bucket aggregations
- EQL
- SQL access
- Overview
- Getting Started with SQL
- Conventions and Terminology
- Security
- SQL REST API
- SQL Translate API
- SQL CLI
- SQL JDBC
- SQL ODBC
- SQL Client Applications
- SQL Language
- Functions and Operators
- Comparison Operators
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- Aggregate Functions
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- Date/Time and Interval Functions and Operators
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- Mathematical Functions
- String Functions
- Type Conversion Functions
- Geo Functions
- Conditional Functions And Expressions
- System Functions
- Reserved keywords
- SQL Limitations
- Scripting
- Data management
- ILM: Manage the index lifecycle
- Overview
- Concepts
- Automate rollover
- Manage Filebeat time-based indices
- Index lifecycle actions
- Configure a lifecycle policy
- Migrate index allocation filters to node roles
- Resolve lifecycle policy execution errors
- Start and stop index lifecycle management
- Manage existing indices
- Skip rollover
- Restore a managed data stream or index
- Monitor a cluster
- Frozen indices
- Roll up or transform your data
- Set up a cluster for high availability
- Snapshot and restore
- Secure a cluster
- Overview
- Configuring security
- User authentication
- Built-in users
- Internal users
- Token-based authentication services
- Realms
- Realm chains
- Active Directory user authentication
- File-based user authentication
- LDAP user authentication
- Native user authentication
- OpenID Connect authentication
- PKI user authentication
- SAML authentication
- Kerberos authentication
- Integrating with other authentication systems
- Enabling anonymous access
- Controlling the user cache
- Configuring SAML single-sign-on on the Elastic Stack
- Configuring single sign-on to the Elastic Stack using OpenID Connect
- User authorization
- Built-in roles
- Defining roles
- Granting access to Stack Management features
- Security privileges
- Document level security
- Field level security
- Granting privileges for data streams and index aliases
- Mapping users and groups to roles
- Setting up field and document level security
- Submitting requests on behalf of other users
- Configuring authorization delegation
- Customizing roles and authorization
- Enabling audit logging
- Encrypting communications
- Restricting connections with IP filtering
- Cross cluster search, clients, and integrations
- Tutorial: Getting started with security
- Tutorial: Encrypting communications
- Troubleshooting
- Some settings are not returned via the nodes settings API
- Authorization exceptions
- Users command fails due to extra arguments
- Users are frequently locked out of Active Directory
- Certificate verification fails for curl on Mac
- SSLHandshakeException causes connections to fail
- Common SSL/TLS exceptions
- Common Kerberos exceptions
- Common SAML issues
- Internal Server Error in Kibana
- Setup-passwords command fails due to connection failure
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- Limitations
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- How To
- Glossary of terms
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- Compact and aligned text (CAT) APIs
- cat aliases
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- Cluster APIs
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- Add index alias
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- Get mapping
- Index alias exists
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- Open index
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- Add events to calendar
- Add jobs to calendar
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- Estimate model memory
- Find file structure
- Flush jobs
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- Get buckets
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- Get influencers
- Get jobs
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- Get machine learning info
- Get model snapshots
- Get overall buckets
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- Open jobs
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- Revert model snapshots
- Set upgrade mode
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- Update datafeeds
- Update filters
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- Machine learning data frame analytics APIs
- Create data frame analytics jobs
- Create trained models
- Update data frame analytics jobs
- Delete data frame analytics jobs
- Delete trained models
- Evaluate data frame analytics
- Explain data frame analytics
- Get data frame analytics jobs
- Get data frame analytics jobs stats
- Get trained models
- Get trained models stats
- Start data frame analytics jobs
- Stop data frame analytics jobs
- Migration APIs
- Reload search analyzers API
- Repositories metering APIs
- Rollup APIs
- Search APIs
- Searchable snapshots APIs
- Security APIs
- Authenticate
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- Clear cache
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- Get API key information
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- Get role mappings
- Get roles
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- Grant API keys
- Has privileges
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- OpenID Connect prepare authentication
- OpenID Connect authenticate
- OpenID Connect logout
- SAML prepare authentication
- SAML authenticate
- SAML logout
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- SSL certificate
- Snapshot and restore APIs
- Snapshot lifecycle management APIs
- Transform APIs
- Usage API
- Watcher APIs
- Definitions
- Migration guide
- Release notes
- Elasticsearch version 7.10.2
- Elasticsearch version 7.10.1
- Elasticsearch version 7.10.0
- Elasticsearch version 7.9.3
- Elasticsearch version 7.9.2
- Elasticsearch version 7.9.1
- Elasticsearch version 7.9.0
- Elasticsearch version 7.8.1
- Elasticsearch version 7.8.0
- Elasticsearch version 7.7.1
- Elasticsearch version 7.7.0
- Elasticsearch version 7.6.2
- Elasticsearch version 7.6.1
- Elasticsearch version 7.6.0
- Elasticsearch version 7.5.2
- Elasticsearch version 7.5.1
- Elasticsearch version 7.5.0
- Elasticsearch version 7.4.2
- Elasticsearch version 7.4.1
- Elasticsearch version 7.4.0
- Elasticsearch version 7.3.2
- Elasticsearch version 7.3.1
- Elasticsearch version 7.3.0
- Elasticsearch version 7.2.1
- Elasticsearch version 7.2.0
- Elasticsearch version 7.1.1
- Elasticsearch version 7.1.0
- Elasticsearch version 7.0.0
- Elasticsearch version 7.0.0-rc2
- Elasticsearch version 7.0.0-rc1
- Elasticsearch version 7.0.0-beta1
- Elasticsearch version 7.0.0-alpha2
- Elasticsearch version 7.0.0-alpha1
- Dependencies and versions
Index Sorting
editIndex Sorting
editWhen creating a new index in Elasticsearch it is possible to configure how the Segments
inside each Shard will be sorted. By default Lucene does not apply any sort.
The index.sort.*
settings define which fields should be used to sort the documents inside each Segment.
nested fields are not compatible with index sorting because they rely on the assumption that nested documents are stored in contiguous doc ids, which can be broken by index sorting. An error will be thrown if index sorting is activated on an index that contains nested fields.
For instance the following example shows how to define a sort on a single field:
PUT my-index-000001 { "settings": { "index": { "sort.field": "date", "sort.order": "desc" } }, "mappings": { "properties": { "date": { "type": "date" } } } }
It is also possible to sort the index by more than one field:
PUT my-index-000001 { "settings": { "index": { "sort.field": [ "username", "date" ], "sort.order": [ "asc", "desc" ] } }, "mappings": { "properties": { "username": { "type": "keyword", "doc_values": true }, "date": { "type": "date" } } } }
This index is sorted by |
|
… in ascending order for the |
Index sorting supports the following settings:
-
index.sort.field
-
The list of fields used to sort the index.
Only
boolean
,numeric
,date
andkeyword
fields withdoc_values
are allowed here. -
index.sort.order
-
The sort order to use for each field. The order option can have the following values:
-
asc
: For ascending order -
desc
: For descending order.
-
-
index.sort.mode
-
Elasticsearch supports sorting by multi-valued fields. The mode option controls what value is picked to sort the document. The mode option can have the following values:
-
min
: Pick the lowest value. -
max
: Pick the highest value.
-
-
index.sort.missing
-
The missing parameter specifies how docs which are missing the field should be treated. The missing value can have the following values:
-
_last
: Documents without value for the field are sorted last. -
_first
: Documents without value for the field are sorted first.
-
Index sorting can be defined only once at index creation. It is not allowed to add or update a sort on an existing index. Index sorting also has a cost in terms of indexing throughput since documents must be sorted at flush and merge time. You should test the impact on your application before activating this feature.
Early termination of search request
editBy default in Elasticsearch a search request must visit every document that match a query to retrieve the top documents sorted by a specified sort. Though when the index sort and the search sort are the same it is possible to limit the number of documents that should be visited per segment to retrieve the N top ranked documents globally. For example, let’s say we have an index that contains events sorted by a timestamp field:
PUT events { "settings": { "index": { "sort.field": "timestamp", "sort.order": "desc" } }, "mappings": { "properties": { "timestamp": { "type": "date" } } } }
You can search for the last 10 events with:
GET /events/_search { "size": 10, "sort": [ { "timestamp": "desc" } ] }
Elasticsearch will detect that the top docs of each segment are already sorted in the index and will only compare the first N documents per segment. The rest of the documents matching the query are collected to count the total number of results and to build aggregations.
If you’re only looking for the last 10 events and have no interest in
the total number of documents that match the query you can set track_total_hits
to false:
The index sort will be used to rank the top documents and each segment will early terminate the collection after the first 10 matches. |
This time, Elasticsearch will not try to count the number of documents and will be able to terminate the query as soon as N documents have been collected per segment.
Aggregations will collect all documents that match the query regardless
of the value of track_total_hits
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