- Elasticsearch Guide: other versions:
- Getting Started
- Set up Elasticsearch
- Installing Elasticsearch
- Configuring Elasticsearch
- Important Elasticsearch configuration
- Important System Configuration
- Bootstrap Checks
- Heap size check
- File descriptor check
- Memory lock check
- Maximum number of threads check
- Maximum size virtual memory check
- Max file size 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
- Stopping Elasticsearch
- Upgrade Elasticsearch
- Set up X-Pack
- Breaking changes
- Breaking changes in 6.0
- Aggregations changes
- Analysis changes
- Cat API changes
- Clients changes
- Cluster changes
- Document API changes
- Indices changes
- Ingest changes
- Java API changes
- Mapping changes
- Packaging changes
- Percolator changes
- Plugins changes
- Reindex changes
- REST changes
- Scripting changes
- Search and Query DSL changes
- Settings changes
- Stats and info changes
- Breaking changes in 6.1
- Breaking changes in 6.0
- X-Pack Breaking Changes
- API Conventions
- Document APIs
- Search APIs
- Aggregations
- Metrics Aggregations
- Avg Aggregation
- Cardinality Aggregation
- Extended Stats Aggregation
- Geo Bounds Aggregation
- Geo Centroid Aggregation
- Max Aggregation
- Min Aggregation
- Percentiles Aggregation
- Percentile Ranks Aggregation
- Scripted Metric Aggregation
- Stats Aggregation
- Sum Aggregation
- Top Hits Aggregation
- Value Count Aggregation
- Bucket Aggregations
- Adjacency Matrix Aggregation
- Children Aggregation
- Composite Aggregation
- Date Histogram Aggregation
- Date Range Aggregation
- Diversified Sampler Aggregation
- Filter Aggregation
- Filters Aggregation
- Geo Distance Aggregation
- GeoHash grid Aggregation
- Global Aggregation
- Histogram Aggregation
- IP Range Aggregation
- Missing Aggregation
- Nested Aggregation
- Range Aggregation
- Reverse nested Aggregation
- Sampler Aggregation
- Significant Terms Aggregation
- Significant Text Aggregation
- Terms Aggregation
- Pipeline Aggregations
- Avg Bucket Aggregation
- Derivative Aggregation
- Max Bucket Aggregation
- Min Bucket Aggregation
- Sum Bucket Aggregation
- Stats Bucket Aggregation
- Extended Stats Bucket Aggregation
- Percentiles Bucket Aggregation
- Moving Average Aggregation
- Cumulative Sum Aggregation
- Bucket Script Aggregation
- Bucket Selector Aggregation
- Bucket Sort Aggregation
- Serial Differencing Aggregation
- Matrix Aggregations
- Caching heavy aggregations
- Returning only aggregation results
- Aggregation Metadata
- Returning the type of the aggregation
- Metrics Aggregations
- Indices APIs
- Create Index
- Delete Index
- Get Index
- Indices Exists
- Open / Close Index API
- Shrink Index
- Split Index
- Rollover Index
- Put Mapping
- Get Mapping
- Get Field Mapping
- Types Exists
- Index Aliases
- Update Indices Settings
- Get Settings
- Analyze
- Index Templates
- Indices Stats
- Indices Segments
- Indices Recovery
- Indices Shard Stores
- Clear Cache
- Flush
- Refresh
- Force Merge
- cat APIs
- Cluster APIs
- Query DSL
- Mapping
- Analysis
- Anatomy of an analyzer
- Testing analyzers
- Analyzers
- Normalizers
- Tokenizers
- Token Filters
- Standard Token Filter
- ASCII Folding Token Filter
- Flatten Graph Token Filter
- Length Token Filter
- Lowercase Token Filter
- Uppercase Token Filter
- NGram Token Filter
- Edge NGram Token Filter
- Porter Stem Token Filter
- Shingle Token Filter
- Stop Token Filter
- Word Delimiter Token Filter
- Word Delimiter Graph Token Filter
- Stemmer Token Filter
- Stemmer Override Token Filter
- Keyword Marker Token Filter
- Keyword Repeat Token Filter
- KStem Token Filter
- Snowball Token Filter
- Phonetic Token Filter
- Synonym Token Filter
- Synonym Graph Token Filter
- Compound Word Token Filters
- Reverse Token Filter
- Elision Token Filter
- Truncate Token Filter
- Unique Token Filter
- Pattern Capture Token Filter
- Pattern Replace Token Filter
- Trim Token Filter
- Limit Token Count Token Filter
- Hunspell Token Filter
- Common Grams Token Filter
- Normalization Token Filter
- CJK Width Token Filter
- CJK Bigram Token Filter
- Delimited Payload Token Filter
- Keep Words Token Filter
- Keep Types Token Filter
- Classic Token Filter
- Apostrophe Token Filter
- Decimal Digit Token Filter
- Fingerprint Token Filter
- Minhash Token Filter
- Character Filters
- Modules
- Index Modules
- Ingest Node
- Pipeline Definition
- Ingest APIs
- Accessing Data in Pipelines
- Handling Failures in Pipelines
- Processors
- Append Processor
- Convert Processor
- Date Processor
- Date Index Name Processor
- Fail Processor
- Foreach Processor
- Grok Processor
- Gsub Processor
- Join Processor
- JSON Processor
- KV Processor
- Lowercase Processor
- Remove Processor
- Rename Processor
- Script Processor
- Set Processor
- Split Processor
- Sort Processor
- Trim Processor
- Uppercase Processor
- Dot Expander Processor
- URL Decode Processor
- Monitoring Elasticsearch
- X-Pack APIs
- Info API
- Explore API
- Machine Learning APIs
- Close Jobs
- Create Datafeeds
- Create Jobs
- Delete Datafeeds
- Delete Jobs
- Delete Model Snapshots
- Flush Jobs
- Forecast Jobs
- Get Buckets
- Get Overall Buckets
- Get Categories
- Get Datafeeds
- Get Datafeed Statistics
- Get Influencers
- Get Jobs
- Get Job Statistics
- Get Model Snapshots
- Get Records
- Open Jobs
- Post Data to Jobs
- Preview Datafeeds
- Revert Model Snapshots
- Start Datafeeds
- Stop Datafeeds
- Update Datafeeds
- Update Jobs
- Update Model Snapshots
- Security APIs
- Watcher APIs
- Migration APIs
- Deprecation Info APIs
- Definitions
- X-Pack Commands
- How To
- Testing
- Glossary of terms
- Release Notes
- 6.1.4 Release Notes
- 6.1.3 Release Notes
- 6.1.2 Release Notes
- 6.1.1 Release Notes
- 6.1.0 Release Notes
- 6.0.1 Release Notes
- 6.0.0 Release Notes
- 6.0.0-rc2 Release Notes
- 6.0.0-rc1 Release Notes
- 6.0.0-beta2 Release Notes
- 6.0.0-beta1 Release Notes
- 6.0.0-alpha2 Release Notes
- 6.0.0-alpha1 Release Notes
- 6.0.0-alpha1 Release Notes (Changes previously released in 5.x)
- X-Pack Release Notes
WARNING: Version 6.1 of Elasticsearch has passed its EOL date.
This documentation is no longer being maintained and may be removed. If you are running this version, we strongly advise you to upgrade. For the latest information, see the current release documentation.
Regexp Query
editRegexp Query
editThe regexp
query allows you to use regular expression term queries.
See Regular expression syntax for details of the supported regular expression language.
The "term queries" in that first sentence means that Elasticsearch will apply
the regexp to the terms produced by the tokenizer for that field, and not
to the original text of the field.
Note: The performance of a regexp
query heavily depends on the
regular expression chosen. Matching everything like .*
is very slow as
well as using lookaround regular expressions. If possible, you should
try to use a long prefix before your regular expression starts. Wildcard
matchers like .*?+
will mostly lower performance.
GET /_search { "query": { "regexp":{ "name.first": "s.*y" } } }
Boosting is also supported
GET /_search { "query": { "regexp":{ "name.first":{ "value":"s.*y", "boost":1.2 } } } }
You can also use special flags
GET /_search { "query": { "regexp":{ "name.first": { "value": "s.*y", "flags" : "INTERSECTION|COMPLEMENT|EMPTY" } } } }
Possible flags are ALL
(default), ANYSTRING
, COMPLEMENT
,
EMPTY
, INTERSECTION
, INTERVAL
, or NONE
. Please check the
Lucene
documentation for their meaning
Regular expressions are dangerous because it’s easy to accidentally
create an innocuous looking one that requires an exponential number of
internal determinized automaton states (and corresponding RAM and CPU)
for Lucene to execute. Lucene prevents these using the
max_determinized_states
setting (defaults to 10000). You can raise
this limit to allow more complex regular expressions to execute.
GET /_search { "query": { "regexp":{ "name.first": { "value": "s.*y", "flags" : "INTERSECTION|COMPLEMENT|EMPTY", "max_determinized_states": 20000 } } } }
Regular expression syntax
editRegular expression queries are supported by the regexp
and the query_string
queries. The Lucene regular expression engine
is not Perl-compatible but supports a smaller range of operators.
We will not attempt to explain regular expressions, but just explain the supported operators.
Standard operators
edit- Anchoring
-
Most regular expression engines allow you to match any part of a string. If you want the regexp pattern to start at the beginning of the string or finish at the end of the string, then you have to anchor it specifically, using
^
to indicate the beginning or$
to indicate the end.Lucene’s patterns are always anchored. The pattern provided must match the entire string. For string
"abcde"
:ab.* # match abcd # no match
- Allowed characters
-
Any Unicode characters may be used in the pattern, but certain characters are reserved and must be escaped. The standard reserved characters are:
. ? + * | { } [ ] ( ) " \
If you enable optional features (see below) then these characters may also be reserved:
# @ & < > ~
Any reserved character can be escaped with a backslash
"\*"
including a literal backslash character:"\\"
Additionally, any characters (except double quotes) are interpreted literally when surrounded by double quotes:
john"@smith.com"
- Match any character
-
The period
"."
can be used to represent any character. For string"abcde"
:ab... # match a.c.e # match
- One-or-more
-
The plus sign
"+"
can be used to repeat the preceding shortest pattern once or more times. For string"aaabbb"
:a+b+ # match aa+bb+ # match a+.+ # match aa+bbb+ # match
- Zero-or-more
-
The asterisk
"*"
can be used to match the preceding shortest pattern zero-or-more times. For string"aaabbb
":a*b* # match a*b*c* # match .*bbb.* # match aaa*bbb* # match
- Zero-or-one
-
The question mark
"?"
makes the preceding shortest pattern optional. It matches zero or one times. For string"aaabbb"
:aaa?bbb? # match aaaa?bbbb? # match .....?.? # match aa?bb? # no match
- Min-to-max
-
Curly brackets
"{}"
can be used to specify a minimum and (optionally) a maximum number of times the preceding shortest pattern can repeat. The allowed forms are:{5} # repeat exactly 5 times {2,5} # repeat at least twice and at most 5 times {2,} # repeat at least twice
For string
"aaabbb"
:a{3}b{3} # match a{2,4}b{2,4} # match a{2,}b{2,} # match .{3}.{3} # match a{4}b{4} # no match a{4,6}b{4,6} # no match a{4,}b{4,} # no match
- Grouping
-
Parentheses
"()"
can be used to form sub-patterns. The quantity operators listed above operate on the shortest previous pattern, which can be a group. For string"ababab"
:(ab)+ # match ab(ab)+ # match (..)+ # match (...)+ # no match (ab)* # match abab(ab)? # match ab(ab)? # no match (ab){3} # match (ab){1,2} # no match
- Alternation
-
The pipe symbol
"|"
acts as an OR operator. The match will succeed if the pattern on either the left-hand side OR the right-hand side matches. The alternation applies to the longest pattern, not the shortest. For string"aabb"
:aabb|bbaa # match aacc|bb # no match aa(cc|bb) # match a+|b+ # no match a+b+|b+a+ # match a+(b|c)+ # match
- Character classes
-
Ranges of potential characters may be represented as character classes by enclosing them in square brackets
"[]"
. A leading^
negates the character class. The allowed forms are:[abc] # 'a' or 'b' or 'c' [a-c] # 'a' or 'b' or 'c' [-abc] # '-' or 'a' or 'b' or 'c' [abc\-] # '-' or 'a' or 'b' or 'c' [^abc] # any character except 'a' or 'b' or 'c' [^a-c] # any character except 'a' or 'b' or 'c' [^-abc] # any character except '-' or 'a' or 'b' or 'c' [^abc\-] # any character except '-' or 'a' or 'b' or 'c'
Note that the dash
"-"
indicates a range of characters, unless it is the first character or if it is escaped with a backslash.For string
"abcd"
:ab[cd]+ # match [a-d]+ # match [^a-d]+ # no match
Optional operators
editThese operators are available by default as the flags
parameter defaults to ALL
.
Different flag combinations (concatenated with "|"
) can be used to enable/disable
specific operators:
{ "regexp": { "username": { "value": "john~athon<1-5>", "flags": "COMPLEMENT|INTERVAL" } } }
- Complement
-
The complement is probably the most useful option. The shortest pattern that follows a tilde
"~"
is negated. For instance, `"ab~cd" means:-
Starts with
a
-
Followed by
b
-
Followed by a string of any length that it anything but
c
-
Ends with
d
For the string
"abcdef"
:ab~df # match ab~cf # match ab~cdef # no match a~(cb)def # match a~(bc)def # no match
Enabled with the
COMPLEMENT
orALL
flags. -
Starts with
- Interval
-
The interval option enables the use of numeric ranges, enclosed by angle brackets
"<>"
. For string:"foo80"
:foo<1-100> # match foo<01-100> # match foo<001-100> # no match
Enabled with the
INTERVAL
orALL
flags. - Intersection
-
The ampersand
"&"
joins two patterns in a way that both of them have to match. For string"aaabbb"
:aaa.+&.+bbb # match aaa&bbb # no match
Using this feature usually means that you should rewrite your regular expression.
Enabled with the
INTERSECTION
orALL
flags. - Any string
-
The at sign
"@"
matches any string in its entirety. This could be combined with the intersection and complement above to express “everything except”. For instance:@&~(foo.+) # anything except string beginning with "foo"
Enabled with the
ANYSTRING
orALL
flags.