Update API

The update API allows to update a document based on a script provided. The operation gets the document (collocated with the shard) from the index, runs the script (with optional script language and parameters), and index back the result (also allows to delete, or ignore the operation). It uses versioning to make sure no updates have happened during the "get" and "reindex".

Note, this operation still means full reindex of the document, it just removes some network roundtrips and reduces chances of version conflicts between the get and the index. The _source field need to be enabled for this feature to work.

For example, lets index a simple doc:

curl -XPUT localhost:9200/test/type1/1 -d '{
    "counter" : 1,
    "tags" : ["red"]
}'

Now, we can execute a script that would increment the counter:

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "script" : "ctx._source.counter += count",
    "params" : {
        "count" : 4
    }
}'

We can also add a tag to the list of tags (note, if the tag exists, it will still add it, since its a list):

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "script" : "ctx._source.tags += tag",
    "params" : {
        "tag" : "blue"
    }
}'

We can also add a new field to the document:

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "script" : "ctx._source.name_of_new_field = \"value_of_new_field\""
}'

We can also remove a field from the document:

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "script" : "ctx._source.remove(\"name_of_field\")"
}'

And, we can delete the doc if the tags contain blue, or ignore (noop):

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "script" : "ctx._source.tags.contains(tag) ? ctx.op = \"delete\" : ctx.op = \"none\"",
    "params" : {
        "tag" : "blue"
    }
}'

Note: Be aware of MVEL and handling of ternary operators and assignments. Assignment operations have lower precedence than the ternary operator. Compare the following statements:

// Will NOT update the tags array
ctx._source.tags.contains(tag) ? ctx.op = \"none\" : ctx._source.tags += tag
// Will update
ctx._source.tags.contains(tag) ? (ctx.op = \"none\") : ctx._source.tags += tag
// Also works
if (ctx._source.tags.contains(tag)) { ctx.op = \"none\" } else { ctx._source.tags += tag }

The update API also support passing a partial document, which will be merged into the existing document (simple recursive merge, inner merging of objects, replacing core "keys/values" and arrays). For example:

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "doc" : {
        "name" : "new_name"
    }
}'

If both doc and script is specified, then doc is ignored. Best is to put your field pairs of the partial document in the script itself.

Upserts

There is also support for upsert. If the document does not already exists, the content of the upsert element will be used to index the fresh doc:

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "script" : "ctx._source.counter += count",
    "params" : {
        "count" : 4
    },
    "upsert" : {
        "counter" : 1
    }
}'

Last, the upsert facility also supports doc_as_upsert. So that the provided document will be inserted if the document does not already exist. This will reduce the amount of data that needs to be sent to elasticsearch.

curl -XPOST 'localhost:9200/test/type1/1/_update' -d '{
    "doc" : {
        "name" : "new_name"
    },
    "doc_as_upsert" : true
}'

Parameters

The update operation supports similar parameters as the index API, including:

routing

Sets the routing that will be used to route the document to the relevant shard.

parent

Simply sets the routing.

timeout

Timeout waiting for a shard to become available.

replication

The replication type for the delete/index operation (sync or async).

consistency

The write consistency of the index/delete operation.

refresh

Refresh the relevant primary and replica shards (not the whole index) immediately after the operation occurs, so that the updated document appears in search results immediately.

fields

return the relevant fields from the updated document. Support _source to return the full updated source.

version & version_type

the Update API uses the Elasticsearch’s versioning support internally to make sure the document doesn’t change during the update. You can use the version parameter to specify that the document should only be updated if it’s version matches the one specified. By setting version type to force you can force the new version of the document after update (use with care! with force there is no guarantee the document didn’t change).Version types external & external_gte are not supported.

And also support retry_on_conflict which controls how many times to retry if there is a version conflict between getting the document and indexing / deleting it. Defaults to 0.

It also allows to update the ttl of a document using ctx._ttl and timestamp using ctx._timestamp. Note that if the timestamp is not updated and not extracted from the _source it will be set to the update date.