Add documentation for pattern_text mapping type (elastic#135856)

Add documentation for pattern_text type. Since the main text page was getting large, create a new text-type-family page with links to text, match_only_text, and pattern_text.

Author: parkertimmins

docs/redirects.yml

@@ -105,3 +105,10 @@ redirects:
   'reference/query-languages/esql/kibana/docs/functions/st_geohash_to_long.md': 'reference/query-languages/esql/esql-functions-operators.md'
   'reference/query-languages/esql/kibana/docs/functions/st_geotile_to_long.md': 'reference/query-languages/esql/esql-functions-operators.md'
   'reference/query-languages/esql/kibana/docs/functions/st_geohex_to_long.md': 'reference/query-languages/esql/esql-functions-operators.md'
+
+  'reference/elasticsearch/mapping-reference/text.md':
+    to: 'reference/elasticsearch/mapping-reference/text.md'
+    anchors: { } # pass-through unlisted anchors in the `many` ruleset
+    many:
+      - to: 'reference/elasticsearch/mapping-reference/match-only-text.md'
+        anchors: { 'match-only-text-field-type', 'match-only-text-params' }

docs/reference/elasticsearch/mapping-reference/field-data-types.md

@@ -77,8 +77,8 @@ Dates
 
 ### Text search types [text-search-types]
 
-[`text` fields](/reference/elasticsearch/mapping-reference/text.md)
-:   The text family, including `text` and `match_only_text`. Analyzed, unstructured text.
+[`text` fields](/reference/elasticsearch/mapping-reference/text-type-family.md)
+:   The text family, including `text`, `match_only_text`, and `pattern_text`. Analyzed, unstructured text.
 
 [`annotated-text`](/reference/elasticsearch-plugins/mapper-annotated-text.md)
 :   Text containing special markup. Used for identifying named entities.

docs/reference/elasticsearch/mapping-reference/match-only-text.md

@@ -0,0 +1,43 @@
+---
+navigation_title: "Match Only Text"
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/reference/current/match-only-text.html
+---
+
+# Match-only text field type [match-only-text-field-type]
+
+A variant of [`text`](/reference/elasticsearch/mapping-reference/text.md) that trades scoring and efficiency of positional queries for space efficiency. This field effectively stores data the same way as a `text` field that only indexes documents (`index_options: docs`) and disables norms (`norms: false`). Term queries perform as fast if not faster as on `text` fields, however queries that need positions such as the [`match_phrase` query](/reference/query-languages/query-dsl/query-dsl-match-query-phrase.md) perform slower as they need to look at the `_source` document to verify whether a phrase matches. All queries return constant scores that are equal to 1.0.
+
+Analysis is not configurable: text is always analyzed with the [default analyzer](docs-content://manage-data/data-store/text-analysis/specify-an-analyzer.md#specify-index-time-default-analyzer) ([`standard`](/reference/text-analysis/analysis-standard-analyzer.md) by default).
+
+[span queries](/reference/query-languages/query-dsl/span-queries.md) are not supported with this field, use [interval queries](/reference/query-languages/query-dsl/query-dsl-intervals-query.md) instead, or the [`text`](/reference/elasticsearch/mapping-reference/text.md) field type if you absolutely need span queries.
+
+Other than that, `match_only_text` supports the same queries as `text`. And like `text`, it does not support sorting and has only limited support for aggregations.
+
+```console
+PUT logs
+{
+  "mappings": {
+    "properties": {
+      "@timestamp": {
+        "type": "date"
+      },
+      "message": {
+        "type": "match_only_text"
+      }
+    }
+  }
+}
+```
+
+
+## Parameters for match-only text fields [match-only-text-params]
+
+The following mapping parameters are accepted:
+
+[`fields`](/reference/elasticsearch/mapping-reference/multi-fields.md)
+:   Multi-fields allow the same string value to be indexed in multiple ways for different purposes, such as one field for search and a multi-field for sorting and aggregations, or the same string value analyzed by different analyzers.
+
+[`meta`](/reference/elasticsearch/mapping-reference/mapping-field-meta.md)
+:   Metadata about the field.
+

docs/reference/elasticsearch/mapping-reference/pattern-text.md

@@ -0,0 +1,85 @@
+---
+navigation_title: "Pattern Text"
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/reference/current/pattern-text.html
+---
+
+# Pattern text field type [pattern-text-field-type]
+```{applies_to}
+serverless: preview
+stack: preview 9.2
+```
+:::{note}
+This feature requires a [subscription](https://www.elastic.co/subscriptions).
+:::
+
+The `pattern_text` field type is a variant of [`text`](/reference/elasticsearch/mapping-reference/text.md) with improved space efficiency for log data.
+Internally, it decomposes values into static parts that are likely to be shared among many values, and dynamic parts that tend to vary.
+The static parts usually come from the explanatory text of a log message, while the dynamic parts are the variables that were interpolated into the logs.
+This decomposition allows for improved compression on log-like data.
+
+We call the static portion of the value the `template`.
+Although the template cannot be accessed directly, a separate field called `<field_name>.template_id` is accessible.
+This field is a hash of the template and can be used to group similar values.
+
+Analysis is configurable but defaults to a delimiter-based analyzer.
+This analyzer applies a lowercase filter and then splits on whitespace and the following delimiters: `=`, `?`, `:`, `[`, `]`, `{`, `}`, `"`, `\`, `'`.
+
+## Limitations
+
+Unlike most mapping types, `pattern_text` does not support multiple values for a given field per document.
+If a document is created with multiple values for a pattern_text field, an error will be returned.
+
+[span queries](/reference/query-languages/query-dsl/span-queries.md) are not supported with this field, use [interval queries](/reference/query-languages/query-dsl/query-dsl-intervals-query.md) instead, or the [`text`](/reference/elasticsearch/mapping-reference/text.md) field type if you absolutely need span queries.
+
+Like `text`, `pattern_text` does not support sorting and has only limited support for aggregations.
+
+## Phrase matching
+Pattern text supports an `index_options` parameter with valid values of `docs` and `positions`.
+The default value is `docs`, which makes `pattern_text` behave similarly to `match_only_text` for phrase queries.
+Specifically, positions are not stored, which reduces the index size at the cost of slowing down phrase queries.
+If `index_options` is set to `positions`, positions are stored and `pattern_text` will support fast phrase queries.
+In both cases, all queries return a constant score of 1.0.
+
+## Index sorting for improved compression
+The compression provided by `pattern_text` can be significantly improved if the index is sorted by the `template_id` field.
+For example, a typical approach would be to sort first by `message.template_id`, then by `@timestamp`, as shown in the following example.
+
+```console
+PUT logs
+{
+  "settings": {
+    "index": {
+      "sort.field": [ "message.template_id", "@timestamp" ],
+      "sort.order": [ "asc", "desc" ]
+    }
+  },
+  "mappings": {
+    "properties": {
+      "@timestamp": {
+        "type": "date"
+      },
+      "message": {
+        "type": "pattern_text"
+      }
+    }
+  }
+}
+```
+
+
+## Parameters for pattern text fields [pattern-text-params]
+
+The following mapping parameters are accepted:
+
+[`analyzer`](/reference/elasticsearch/mapping-reference/analyzer.md)
+:   The [analyzer](docs-content://manage-data/data-store/text-analysis.md) which should be used for the `pattern_text` field, both at index-time and at search-time (unless overridden by the  [`search_analyzer`](/reference/elasticsearch/mapping-reference/search-analyzer.md)).
+Supports a delimiter-based analyzer and the standard analyzer, as is used in `match_only_text` mappings.
+Defaults to the delimiter-based analyzer, which applies a lowercase filter and then splits on whitespace and the following delimiters: `=`, `?`, `:`, `[`, `]`, `{`, `}`, `"`, `\`, `'`.
+
+[`index_options`](/reference/elasticsearch/mapping-reference/index-options.md)
+:   What information should be stored in the index, for search and highlighting purposes. Valid values are `docs` and `positions`. Defaults to `docs`.
+
+[`meta`](/reference/elasticsearch/mapping-reference/mapping-field-meta.md)
+:   Metadata about the field.
+

docs/reference/elasticsearch/mapping-reference/text-type-family.md

@@ -0,0 +1,15 @@
+---
+navigation_title: "Text type family"
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/reference/current/text-type-family.html
+---
+
+# Text type family [text]
+
+
+The text family includes the following field types:
+
+* [`text`](/reference/elasticsearch/mapping-reference/text.md), the traditional field type for full-text content such as the body of an email or the description of a product.
+* [`match_only_text`](/reference/elasticsearch/mapping-reference/match-only-text.md), a variant of `text` field type with limited functionality. Scoring is always disabled and the `standard` analyzer is always used. It suited for match only free text uses cases. Meaning that the fact that there is a match is important, but scoring and where the match happens is not relevant. Note that positional queries are possible, but are slow.
+* [`pattern_text`](/reference/elasticsearch/mapping-reference/pattern-text.md), a variant of `text` which is optimized for space efficient storage of log messages. Pattern text reduces space usage for messages that contain many repeated sequences, like the explanatory text of a log message. Pattern text also disables scoring, but unlike `match_only_text`, positional data can be stored for fast phrase queries.
+

docs/reference/elasticsearch/mapping-reference/text.md

@@ -4,16 +4,7 @@ mapped_pages:
   - https://www.elastic.co/guide/en/elasticsearch/reference/current/text.html
 ---
 
-# Text type family [text]
-
-
-The text family includes the following field types:
-
-* [`text`](#text-field-type), the traditional field type for full-text content such as the body of an email or the description of a product.
-* [`match_only_text`](#match-only-text-field-type), a space-optimized variant of `text` that disables scoring and performs slower on queries that need positions. It is best suited for indexing log messages.
-
-
-## Text field type [text-field-type]
+# Text field type [text-field-type]
 
 A field to index full-text values, such as the body of an email or the description of a product. These fields are `analyzed`, that is they are passed through an [analyzer](docs-content://manage-data/data-store/text-analysis.md) to convert the string into a list of individual terms before being indexed. The analysis process allows Elasticsearch to search for individual words *within* each full text field. Text fields are not used for sorting and seldom used for aggregations (although the [significant text aggregation](/reference/aggregations/search-aggregations-bucket-significanttext-aggregation.md) is a notable exception).
 
@@ -304,43 +295,3 @@ PUT my-index-000001
   }
 }
 ```
-
-
-## Match-only text field type [match-only-text-field-type]
-
-A variant of [`text`](#text-field-type) that trades scoring and efficiency of positional queries for space efficiency. This field effectively stores data the same way as a `text` field that only indexes documents (`index_options: docs`) and disables norms (`norms: false`). Term queries perform as fast if not faster as on `text` fields, however queries that need positions such as the [`match_phrase` query](/reference/query-languages/query-dsl/query-dsl-match-query-phrase.md) perform slower as they need to look at the `_source` document to verify whether a phrase matches. All queries return constant scores that are equal to 1.0.
-
-Analysis is not configurable: text is always analyzed with the [default analyzer](docs-content://manage-data/data-store/text-analysis/specify-an-analyzer.md#specify-index-time-default-analyzer) ([`standard`](/reference/text-analysis/analysis-standard-analyzer.md) by default).
-
-[span queries](/reference/query-languages/query-dsl/span-queries.md) are not supported with this field, use [interval queries](/reference/query-languages/query-dsl/query-dsl-intervals-query.md) instead, or the [`text`](#text-field-type) field type if you absolutely need span queries.
-
-Other than that, `match_only_text` supports the same queries as `text`. And like `text`, it does not support sorting and has only limited support for aggregations.
-
-```console
-PUT logs
-{
-  "mappings": {
-    "properties": {
-      "@timestamp": {
-        "type": "date"
-      },
-      "message": {
-        "type": "match_only_text"
-      }
-    }
-  }
-}
-```
-
-
-### Parameters for match-only text fields [match-only-text-params]
-
-The following mapping parameters are accepted:
-
-[`fields`](/reference/elasticsearch/mapping-reference/multi-fields.md)
-:   Multi-fields allow the same string value to be indexed in multiple ways for different purposes, such as one field for search and a multi-field for sorting and aggregations, or the same string value analyzed by different analyzers.
-
-[`meta`](/reference/elasticsearch/mapping-reference/mapping-field-meta.md)
-:   Metadata about the field.
-
-

docs/reference/elasticsearch/rest-apis/highlighting-settings.md

@@ -51,10 +51,10 @@ encoder
 :   Indicates if the snippet should be HTML encoded: `default` (no encoding) or `html` (HTML-escape the snippet text and then insert the highlighting tags)
 
 fields
-:   Specifies the fields to retrieve highlights for. You can use wildcards to specify fields. For example, you could specify `comment_*` to get highlights for all [text](/reference/elasticsearch/mapping-reference/text.md), [match_only_text](/reference/elasticsearch/mapping-reference/text.md#match-only-text-field-type), and [keyword](/reference/elasticsearch/mapping-reference/keyword.md) fields that start with `comment_`.
+:   Specifies the fields to retrieve highlights for. You can use wildcards to specify fields. For example, you could specify `comment_*` to get highlights for all [text](/reference/elasticsearch/mapping-reference/text.md), [match_only_text](/reference/elasticsearch/mapping-reference/match-only-text.md), [pattern_text](/reference/elasticsearch/mapping-reference/pattern-text.md), and [keyword](/reference/elasticsearch/mapping-reference/keyword.md) fields that start with `comment_`.
 
     ::::{note}
-    Only text, match_only_text, and keyword fields are highlighted when you use wildcards. If you use a custom mapper and want to highlight on a field anyway, you must explicitly specify that field name.
+    Only text, match_only_text, pattern_text, and keyword fields are highlighted when you use wildcards. If you use a custom mapper and want to highlight on a field anyway, you must explicitly specify that field name.
     ::::
 
 $$$fragmenter$$$
@@ -147,4 +147,4 @@ tags_schema
 $$$highlighter-type$$$
 
 type
-:   The highlighter to use: `unified`, `plain`, or `fvh`. Defaults to `unified`.
+:   The highlighter to use: `unified`, `plain`, or `fvh`. Defaults to `unified`.

docs/reference/elasticsearch/toc.yml

@@ -174,7 +174,11 @@ toc:
           - file: mapping-reference/semantic-text.md
           - file: mapping-reference/shape.md
           - file: mapping-reference/sparse-vector.md
-          - file: mapping-reference/text.md
+          - file: mapping-reference/text-type-family.md
+            children:
+            - file: mapping-reference/text.md
+            - file: mapping-reference/pattern-text.md
+            - file: mapping-reference/match-only-text.md
           - file: mapping-reference/token-count.md
           - file: mapping-reference/unsigned-long.md
           - file: mapping-reference/version.md