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Remove references to 'mapping type' section. #1440

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Mar 17, 2020
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2 changes: 1 addition & 1 deletion docs/src/reference/asciidoc/core/mapping.adoc
Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ Note that typically handling of these types poses no issues for the user whether
By default, {es} provides {ref}/docs-index_.html[automatic index and mapping] when data is added under an index that has not been created before. In other words, data can be added into {es} without the index and the mappings being defined a priori. This is quite convenient since {es} automatically adapts to the data being fed to it - moreover, if certain entries have extra fields, {es} schema-less nature allows them to be indexed without any issues.

[[auto-mapping-type-loss]]
It is important to remember that automatic mapping uses the payload values to identify its {ref}/mapping.html#mapping-type[type], using the *first document* creates the mapping. {eh} communicates with {es} through JSON which does not provide any type information, rather only the field names and their values. One can think of it as 'type erasure' or information loss; for example JSON does not differentiate integer numeric types - `byte`, `short`, `int`, `long` are all placed in the same `long` 'bucket'. this can have unexpected side-effects since the type information is _guessed_ such as:
It is important to remember that automatic mapping uses the payload values to identify the {ref}/mapping.html#field-datatypes[field types], using the *first document* that adds each field. {eh} communicates with {es} through JSON which does not provide any type information, rather only the field names and their values. One can think of it as 'type erasure' or information loss; for example JSON does not differentiate integer numeric types - `byte`, `short`, `int`, `long` are all placed in the same `long` 'bucket'. this can have unexpected side-effects since the type information is _guessed_ such as:

[float]
===== numbers mapped only as `long`/`double`
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2 changes: 1 addition & 1 deletion docs/src/reference/asciidoc/core/mr.adoc
Original file line number Diff line number Diff line change
Expand Up @@ -381,7 +381,7 @@ conf.set("es.resource.write", "sink/group");

IMPORTANT: If automatic index creation is used, please review <<auto-mapping-type-loss,this>> section for more information.

{eh} automatically converts Hadoop built-in `Writable` types to {es} {ref}/mapping.html#mapping-type[types] (and back) as shown in the table below:
{eh} automatically converts Hadoop built-in `Writable` types to {es} {ref}/mapping.html#field-datatypes[field types] (and back) as shown in the table below:

.`Writable` Conversion Table

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