68 lines
2.0 KiB
Plaintext
68 lines
2.0 KiB
Plaintext
[[mapping-ttl-field]]
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=== `_ttl`
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A lot of documents naturally come with an expiration date. Documents can
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therefore have a `_ttl` (time to live), which will cause the expired
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documents to be deleted automatically.
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`_ttl` accepts two parameters which are described below, every other setting will be silently ignored.
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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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"_ttl" : { "enabled" : true }
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}
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}
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--------------------------------------------------
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`_ttl` can only be enabled once and never be disabled again.
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[float]
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==== default
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You can provide a per index/type default `_ttl` value as follows:
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[source,js]
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--------------------------------------------------
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{
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"tweet" : {
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"_ttl" : { "enabled" : true, "default" : "1d" }
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}
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}
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--------------------------------------------------
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In this case, if you don't provide a `_ttl` value in your query or in
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the `_source` all tweets will have a `_ttl` of one day.
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In case you do not specify a time unit like `d` (days), `m` (minutes),
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`h` (hours), `ms` (milliseconds) or `w` (weeks), milliseconds is used as
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default unit.
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If no `default` is set and no `_ttl` value is given then the document
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has an infinite `_ttl` and will not expire.
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You can dynamically update the `default` value using the put mapping
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API. It won't change the `_ttl` of already indexed documents but will be
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used for future documents.
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[float]
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==== Note on documents expiration
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Expired documents will be automatically deleted regularly. You can
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dynamically set the `indices.ttl.interval` to fit your needs. The
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default value is `60s`.
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The deletion orders are processed by bulk. You can set
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`indices.ttl.bulk_size` to fit your needs. The default value is `10000`.
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Note that the expiration procedure handle versioning properly so if a
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document is updated between the collection of documents to expire and
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the delete order, the document won't be deleted.
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