[[breaking_50_mapping_changes]] === Mapping changes ==== `string` fields replaced by `text`/`keyword` fields The `string` field datatype has been replaced by the `text` field for full text analyzed content, and the `keyword` field for not-analyzed exact string values. For backwards compatibility purposes, during the 5.x series: * `string` fields on pre-5.0 indices will function as before. * New `string` fields can be added to pre-5.0 indices as before. * `text` and `keyword` fields can also be added to pre-5.0 indices. * When adding a `string` field to a new index, the field mapping will be rewritten as a `text` or `keyword` field if possible, otherwise an exception will be thrown. Certain configurations that were possible with `string` fields are no longer possible with `text`/`keyword` fields such as enabling `term_vectors` on a not-analyzed `keyword` field. ==== Default string mappings String mappings now have the following default mappings: [source,js] --------------- { "type": "text", "fields": { "keyword": { "type": "keyword", "ignore_above": 256 } } } --------------- This allows to perform full-text search on the original field name and to sort and run aggregations on the sub keyword field. ==== Numeric fields Numeric fields are now indexed with a completely different data-structure, called BKD tree, that is expected to require less disk space and be faster for range queries than the previous way that numerics were indexed. Term queries will return constant scores now, while they used to return higher scores for rare terms due to the contribution of the document frequency, which this new BKD structure does not record. If scoring is needed, then it is advised to map the numeric fields as <> too. Note that this <> mapping do not need to replace the numeric mapping. For instance if you need both sorting and scoring on your numeric field, you could map it both as a number and a `keyword` using <>: [source,js] -------------------------------------------------- PUT my_index { "mappings": { "my_type": { "properties": { "my_number": { "type": "long", "fields": { "keyword": { "type": "keyword" } } } } } } } -------------------------------------------------- // CONSOLE Also the `precision_step` parameter is now irrelevant and will be rejected on indices that are created on or after 5.0. ==== `index` property On all field datatypes (except for the deprecated `string` field), the `index` property now only accepts `true`/`false` instead of `not_analyzed`/`no`. The `string` field still accepts `analyzed`/`not_analyzed`/`no`. ==== Doc values on unindexed fields Previously, setting a field to `index:no` would also disable doc-values. Now, doc-values are always enabled on numeric and boolean fields unless `doc_values` is set to `false`. ==== Floating points use `float` instead of `double` When dynamically mapping a field containing a floating point number, the field now defaults to using `float` instead of `double`. The reasoning is that floats should be more than enough for most cases but would decrease storage requirements significantly. ==== `norms` `norms` now take a boolean instead of an object. This boolean is the replacement for `norms.enabled`. There is no replacement for `norms.loading` since eager loading of norms is not useful anymore now that norms are disk-based. ==== `fielddata.format` Setting `fielddata.format: doc_values` in the mappings used to implicitly enable doc-values on a field. This no longer works: the only way to enable or disable doc-values is by using the `doc_values` property of mappings. ==== `fielddata.filter.regex` Regex filters are not supported anymore and will be dropped on upgrade. ==== Source-transform removed The source `transform` feature has been removed. Instead, use an ingest pipeline ==== `_parent` field no longer indexed The join between parent and child documents no longer relies on indexed fields and therefore from 5.0.0 onwards the `_parent` field is no longer indexed. In order to find documents that refer to a specific parent id, the new `parent_id` query can be used. The GET response and hits inside the search response still include the parent id under the `_parent` key. ==== Source `format` option The `_source` mapping no longer supports the `format` option. It will still be accepted for indices created before the upgrade to 5.0 for backwards compatibility, but it will have no effect. Indices created on or after 5.0 will reject this option. ==== Object notation Core types no longer support the object notation, which was used to provide per document boosts as follows: [source,js] --------------- { "value": "field_value", "boost": 42 } --------------- ==== Boost accuracy for queries on `_all` Per-field boosts on the `_all` are now compressed into a single byte instead of the 4 bytes used previously. While this will make the index much more space-efficient, it also means that index time boosts will be less accurately encoded.