130 lines
3.6 KiB
Plaintext
130 lines
3.6 KiB
Plaintext
[[mapping-timestamp-field]]
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=== `_timestamp`
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The `_timestamp` field allows to automatically index the timestamp of a
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document. It can be provided externally via the index request or in the
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`_source`. If it is not provided externally it will be automatically set
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to a <<mapping-timestamp-field-default,default date>>.
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[float]
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==== enabled
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By default it is disabled. In order to enable it, the following mapping
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should be defined:
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[source,js]
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--------------------------------------------------
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{
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"tweet" : {
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"_timestamp" : { "enabled" : true }
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}
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}
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--------------------------------------------------
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[float]
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==== store / index
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By default the `_timestamp` field has `store` set to `true` and `index`
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set to `not_analyzed`. It can be queried as a standard date field.
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[float]
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==== path
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The `_timestamp` value can be provided as an external value when
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indexing. But, it can also be automatically extracted from the document
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to index based on a `path`. For example, having the following mapping:
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[source,js]
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--------------------------------------------------
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{
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"tweet" : {
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"_timestamp" : {
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"enabled" : true,
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"path" : "post_date"
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}
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}
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}
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--------------------------------------------------
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Will cause `2009-11-15T14:12:12` to be used as the timestamp value for:
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[source,js]
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--------------------------------------------------
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{
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"message" : "You know, for Search",
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"post_date" : "2009-11-15T14:12:12"
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}
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--------------------------------------------------
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Note, using `path` without explicit timestamp value provided requires an
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additional (though quite fast) parsing phase.
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[float]
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[[mapping-timestamp-field-format]]
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==== format
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You can define the <<mapping-date-format,date
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format>> used to parse the provided timestamp value. For example:
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[source,js]
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--------------------------------------------------
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{
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"tweet" : {
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"_timestamp" : {
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"enabled" : true,
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"path" : "post_date",
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"format" : "YYYY-MM-dd"
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}
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}
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}
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--------------------------------------------------
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Note, the default format is `dateOptionalTime`. The timestamp value will
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first be parsed as a number and if it fails the format will be tried.
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[float]
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[[mapping-timestamp-field-default]]
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==== default
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You can define a default value for when timestamp is not provided
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within the index request or in the `_source` document.
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By default, the default value is `now` which means the date the document was processed by the indexing chain.
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You can reject documents which do not provide a `timestamp` value by setting `ignore_missing` to false (default to `true`):
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[source,js]
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--------------------------------------------------
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{
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"tweet" : {
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"_timestamp" : {
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"enabled" : true,
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"ignore_missing" : false
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}
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}
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}
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--------------------------------------------------
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You can also set the default value to any date respecting <<mapping-timestamp-field-format,timestamp format>>:
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[source,js]
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--------------------------------------------------
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{
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"tweet" : {
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"_timestamp" : {
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"enabled" : true,
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"format" : "YYYY-MM-dd",
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"default" : "1970-01-01"
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}
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}
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}
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--------------------------------------------------
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If you don't provide any timestamp value, _timestamp will be set to this default value.
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In elasticsearch 1.4, we allowed setting explicitly `"default":null` which is not possible anymore
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as we added a new `ignore_missing` setting.
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When reading an index created with elasticsearch 1.4 and using this, we automatically update it by
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removing `"default": null` and setting `"ignore_missing": false`
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