_ttl

A lot of documents naturally come with an expiration date. Documents can therefore have a _ttl (time to live), which will cause the expired documents to be deleted automatically.

_ttl accepts two parameters which are described below, every other setting will be silently ignored.

By default it is disabled, in order to enable it, the following mapping should be defined:

{
    "tweet" : {
        "_ttl" : { "enabled" : true }
    }
}

_ttl can only be enabled once and never be disabled again.

You can provide a per index/type default _ttl value as follows:

{
    "tweet" : {
        "_ttl" : { "enabled" : true, "default" : "1d" }
    }
}

In this case, if you don’t provide a _ttl value in your query or in the _source all tweets will have a _ttl of one day.

In case you do not specify a time unit like d (days), m (minutes), h (hours), ms (milliseconds) or w (weeks), milliseconds is used as default unit.

If no default is set and no _ttl value is given then the document has an infinite _ttl and will not expire.

You can dynamically update the default value using the put mapping API. It won’t change the _ttl of already indexed documents but will be used for future documents.

Expired documents will be automatically deleted regularly. You can dynamically set the indices.ttl.interval to fit your needs. The default value is 60s.

The deletion orders are processed by bulk. You can set indices.ttl.bulk_size to fit your needs. The default value is 10000.

Note that the expiration procedure handle versioning properly so if a document is updated between the collection of documents to expire and the delete order, the document won’t be deleted.