Delete By Query API

The delete by query API allows to delete documents from one or more indices and one or more types based on a query. The query can either be provided using a simple query string as a parameter, or using the Query DSL defined within the request body. Here is an example:

$ curl -XDELETE 'http://localhost:9200/twitter/tweet/_query?q=user:kimchy'

$ curl -XDELETE 'http://localhost:9200/twitter/tweet/_query' -d '{
    "term" : { "user" : "kimchy" }
}
'

Both above examples end up doing the same thing, which is delete all tweets from the twitter index for a certain user. The result of the commands is:

{
    "ok" : true,
    "_indices" : {
        "twitter" : {
            "_shards" : {
                "total" : 5,
                "successful" : 5,
                "failed" : 0
            }
        }
    }
}

Note, delete by query bypasses versioning support. Also, it is not recommended to delete "large chunks of the data in an index", many times, it’s better to simply reindex into a new index.

The delete by query API can be applied to multiple types within an index, and across multiple indices. For example, we can delete all documents across all types within the twitter index:

$ curl -XDELETE 'http://localhost:9200/twitter/_query?q=user:kimchy'

We can also delete within specific types:

$ curl -XDELETE 'http://localhost:9200/twitter/tweet,user/_query?q=user:kimchy'

We can also delete all tweets with a certain tag across several indices (for example, when each user has his own index):

$ curl -XDELETE 'http://localhost:9200/kimchy,elasticsearch/_query?q=tag:wow'

Or even delete across all indices:

$ curl -XDELETE 'http://localhost:9200/_all/_query?q=tag:wow'

When executing a delete by query using the query parameter q, the query passed is a query string using Lucene query parser. There are additional parameters that can be passed:

The delete by query can use the Query DSL within its body in order to express the query that should be executed and delete all documents. The body content can also be passed as a REST parameter named source.

The delete by query API is broadcast across all primary shards, and from there, replicated across all shards replicas.

The routing value (a comma separated list of the routing values) can be specified to control which shards the delete by query request will be executed on.

The replication of the operation can be done in an asynchronous manner to the replicas (the operation will return once it has be executed on the primary shard). The replication parameter can be set to async (defaults to sync) in order to enable it.

Control if the operation will be allowed to execute based on the number of active shards within that partition (replication group). The values allowed are one, quorum, and all. The parameter to set it is consistency, and it defaults to the node level setting of action.write_consistency which in turn defaults to quorum.

For example, in a N shards with 2 replicas index, there will have to be at least 2 active shards within the relevant partition (quorum) for the operation to succeed. In a N shards with 1 replica scenario, there will need to be a single shard active (in this case, one and quorum is the same).