[ES|QL] Add support BYTE_LENGTH scalar function (elastic#116591)

Also added documentation and examples for BIT_LENGTH and LENGTH regarding unicode.

docs/changelog/116591.yaml

@@ -0,0 +1,5 @@
+pr: 116591
+summary: "Add support for `BYTE_LENGTH` scalar function"
+area: ES|QL
+type: feature
+issues: []

docs/reference/esql/functions/string-functions.asciidoc

@@ -9,6 +9,7 @@
 
 // tag::string_list[]
 * <<esql-bit_length>>
+* <<esql-byte_length>>
 * <<esql-concat>>
 * <<esql-ends_with>>
 * <<esql-from_base64>>
@@ -32,6 +33,7 @@
 // end::string_list[]
 
 include::layout/bit_length.asciidoc[]
+include::layout/byte_length.asciidoc[]
 include::layout/concat.asciidoc[]
 include::layout/ends_with.asciidoc[]
 include::layout/from_base64.asciidoc[]

x-pack/plugin/esql/qa/testFixtures/src/main/resources/docs.csv-spec

@@ -4,7 +4,7 @@
 // the comments in whatever file the test already lives in. If you have to
 // write a new test to make an example in the docs then put it in whatever
 // file matches its "theme" best. Put it next to similar tests. Not here.
- 
+
 // Also! When Nik originally extracted examples from the docs to make them
 // testable he didn't spend a lot of time putting the docs into appropriate
 // files. He just made this one. He didn't put his toys away. We'd be better
@@ -352,26 +352,26 @@ FROM employees
 
 // tag::case-result[]
 emp_no:integer | languages:integer| type:keyword
-10001          | 2                |bilingual      
-10002          | 5                |polyglot       
-10003          | 4                |polyglot       
-10004          | 5                |polyglot       
-10005          | 1                |monolingual    
+10001          | 2                |bilingual
+10002          | 5                |polyglot
+10003          | 4                |polyglot
+10004          | 5                |polyglot
+10005          | 1                |monolingual
 // end::case-result[]
 ;
 
 docsCountAll
 // tag::countAll[]
-FROM employees 
-| STATS count = COUNT(*) BY languages 
+FROM employees
+| STATS count = COUNT(*) BY languages
 | SORT languages DESC
 // end::countAll[]
 ;
 
 // tag::countAll-result[]
 count:long | languages:integer
 10         |null
-21         |5 
+21         |5
 18         |4
 17         |3
 19         |2
@@ -381,8 +381,8 @@ count:long | languages:integer
 
 basicGrok
 // tag::basicGrok[]
-ROW a = "2023-01-23T12:15:00.000Z 127.0.0.1 [email protected] 42" 
-| GROK a """%{TIMESTAMP_ISO8601:date} %{IP:ip} %{EMAILADDRESS:email} %{NUMBER:num}""" 
+ROW a = "2023-01-23T12:15:00.000Z 127.0.0.1 [email protected] 42"
+| GROK a """%{TIMESTAMP_ISO8601:date} %{IP:ip} %{EMAILADDRESS:email} %{NUMBER:num}"""
 | KEEP date, ip, email, num
 // end::basicGrok[]
 ;
@@ -395,8 +395,8 @@ date:keyword          | ip:keyword    | email:keyword       | num:keyword
 
 grokWithConversionSuffix
 // tag::grokWithConversionSuffix[]
-ROW a = "2023-01-23T12:15:00.000Z 127.0.0.1 [email protected] 42" 
-| GROK a """%{TIMESTAMP_ISO8601:date} %{IP:ip} %{EMAILADDRESS:email} %{NUMBER:num:int}""" 
+ROW a = "2023-01-23T12:15:00.000Z 127.0.0.1 [email protected] 42"
+| GROK a """%{TIMESTAMP_ISO8601:date} %{IP:ip} %{EMAILADDRESS:email} %{NUMBER:num:int}"""
 | KEEP date, ip, email, num
 // end::grokWithConversionSuffix[]
 ;
@@ -409,8 +409,8 @@ date:keyword              | ip:keyword    | email:keyword       | num:integer
 
 grokWithToDatetime
 // tag::grokWithToDatetime[]
-ROW a = "2023-01-23T12:15:00.000Z 127.0.0.1 [email protected] 42" 
-| GROK a """%{TIMESTAMP_ISO8601:date} %{IP:ip} %{EMAILADDRESS:email} %{NUMBER:num:int}""" 
+ROW a = "2023-01-23T12:15:00.000Z 127.0.0.1 [email protected] 42"
+| GROK a """%{TIMESTAMP_ISO8601:date} %{IP:ip} %{EMAILADDRESS:email} %{NUMBER:num:int}"""
 | KEEP date, ip, email, num
 | EVAL date = TO_DATETIME(date)
 // end::grokWithToDatetime[]
@@ -471,7 +471,7 @@ Tokyo             | 100-7014         | null
 
 basicDissect
 // tag::basicDissect[]
-ROW a = "2023-01-23T12:15:00.000Z - some text - 127.0.0.1" 
+ROW a = "2023-01-23T12:15:00.000Z - some text - 127.0.0.1"
 | DISSECT a """%{date} - %{msg} - %{ip}"""
 | KEEP date, msg, ip
 // end::basicDissect[]
@@ -485,8 +485,8 @@ date:keyword             | msg:keyword  | ip:keyword
 
 dissectWithToDatetime
 // tag::dissectWithToDatetime[]
-ROW a = "2023-01-23T12:15:00.000Z - some text - 127.0.0.1" 
-| DISSECT a """%{date} - %{msg} - %{ip}""" 
+ROW a = "2023-01-23T12:15:00.000Z - some text - 127.0.0.1"
+| DISSECT a """%{date} - %{msg} - %{ip}"""
 | KEEP date, msg, ip
 | EVAL date = TO_DATETIME(date)
 // end::dissectWithToDatetime[]
@@ -574,8 +574,8 @@ FROM employees
 
 // tag::like-result[]
 first_name:keyword  | last_name:keyword
-Ebbe           |Callaway    
-Eberhardt      |Terkki         
+Ebbe           |Callaway
+Eberhardt      |Terkki
 // end::like-result[]
 ;
 
@@ -589,7 +589,7 @@ FROM employees
 
 // tag::rlike-result[]
 first_name:keyword  | last_name:keyword
-Alejandro      |McAlpine     
+Alejandro      |McAlpine
 // end::rlike-result[]
 ;
 
@@ -660,18 +660,19 @@ FROM sample_data
 docsBitLength
 required_capability: fn_bit_length
 // tag::bitLength[]
-FROM employees
-| KEEP first_name, last_name
-| EVAL fn_bit_length = BIT_LENGTH(first_name)
+FROM airports
+| WHERE country == "India"
+| KEEP city
+| EVAL fn_length=LENGTH(city), fn_bit_length = BIT_LENGTH(city)
 // end::bitLength[]
-| SORT first_name
+| SORT city
 | LIMIT 3
 ;
 
 // tag::bitLength-result[]
-first_name:keyword   | last_name:keyword   | fn_bit_length:integer
-Alejandro      |McAlpine       |72              
-Amabile        |Gomatam        |56              
-Anneke         |Preusig        |48
+city:keyword  | fn_length:integer | fn_bit_length:integer
+Agwār         | 5                 | 48
+Ahmedabad     | 9                 | 72
+Bangalore     | 9                 | 72
 // end::bitLength-result[]
 ;