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Adds a new `index.mapping.total_fields.ignore_dynamic_beyond_limit` index setting. When set to `true`, new fields are added to the mapping as long as the field limit (`index.mapping.total_fields.limit`) is not exceeded. Fields that would exceed the limit are not added to the mapping, similar to `dynamic: false`. Ignored fields are added to the `_ignored` metadata field. Relates to https://github.com/elastic/elasticsearch/issues/89911 To make this easier to review, this is split into the following PRs: - [x] https://github.com/elastic/elasticsearch/pull/102915 - [x] https://github.com/elastic/elasticsearch/pull/102936 - [x] https://github.com/elastic/elasticsearch/pull/104769 Related but not a prerequisite: - [ ] https://github.com/elastic/elasticsearch/pull/102885
61 lines
3.3 KiB
Text
61 lines
3.3 KiB
Text
[[mapping-settings-limit]]
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== Mapping limit settings
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Use the following settings to limit the number of field mappings (created manually or dynamically) and prevent documents from causing a mapping explosion:
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`index.mapping.total_fields.limit`::
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The maximum number of fields in an index. Field and object mappings, as well as
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field aliases count towards this limit. Mapped runtime fields count towards this
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limit as well. The default value is `1000`.
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+
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[IMPORTANT]
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====
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The limit is in place to prevent mappings and searches from becoming too
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large. Higher values can lead to performance degradations and memory issues,
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especially in clusters with a high load or few resources.
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If you increase this setting, we recommend you also increase the
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<<search-settings,`indices.query.bool.max_clause_count`>> setting, which
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limits the maximum number of clauses in a query.
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====
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+
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[TIP]
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====
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If your field mappings contain a large, arbitrary set of keys, consider using the <<flattened,flattened>> data type,
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or setting the index setting `index.mapping.total_fields.ignore_dynamic_beyond_limit` to `true`.
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====
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`index.mapping.total_fields.ignore_dynamic_beyond_limit`::
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This setting determines what happens when a dynamically mapped field would exceed the total fields limit.
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When set to `false` (the default), the index request of the document that tries to add a dynamic field to the mapping will fail with the message `Limit of total fields [X] has been exceeded`.
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When set to `true`, the index request will not fail.
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Instead, fields that would exceed the limit are not added to the mapping, similar to <<dynamic, `dynamic: false`>>.
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The fields that were not added to the mapping will be added to the <<mapping-ignored-field, `_ignored` field>>.
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The default value is `false`.
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`index.mapping.depth.limit`::
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The maximum depth for a field, which is measured as the number of inner
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objects. For instance, if all fields are defined at the root object level,
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then the depth is `1`. If there is one object mapping, then the depth is
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`2`, etc. Default is `20`.
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// tag::nested-fields-limit[]
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`index.mapping.nested_fields.limit`::
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The maximum number of distinct `nested` mappings in an index. The `nested` type should only be used in special cases, when arrays of objects need to be queried independently of each other. To safeguard against poorly designed mappings, this setting
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limits the number of unique `nested` types per index. Default is `50`.
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// end::nested-fields-limit[]
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// tag::nested-objects-limit[]
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`index.mapping.nested_objects.limit`::
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The maximum number of nested JSON objects that a single document can contain across all
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`nested` types. This limit helps to prevent out of memory errors when a document contains too many nested
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objects. Default is `10000`.
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// end::nested-objects-limit[]
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`index.mapping.field_name_length.limit`::
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Setting for the maximum length of a field name. This setting isn't really something that addresses
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mappings explosion but might still be useful if you want to limit the field length.
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It usually shouldn't be necessary to set this setting. The default is okay
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unless a user starts to add a huge number of fields with really long names. Default is
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`Long.MAX_VALUE` (no limit).
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include::{es-repo-dir}/data-streams/tsds-index-settings.asciidoc[tag=dimensions-limit]
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