Elasticsearch Bulk API

BULK API

The bulk API makes it possible to perform many index/delete operations in a single API call. This can greatly increase the indexing speed.

Client support for bulk requests

Some of the officially supported clients provide helpers to assist with bulk requests and reindexing of documents from one index to another:

The REST API endpoint is /_bulk, and it expects the following JSON structure:

action_and_meta_datan optional_sourcen action_and_meta_datan optional_sourcen action_and_meta_datan optional_sourcen

NOTE: the final line of data must end with a newline character n.

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The possible actions are index, create, delete and update. index and create expect a source on the next line, and have the same semantics as the op_type parameter to the standard index API (i.e. create will fail if a document with the same index and type exists already, whereas index will add or replace a document as necessary). delete does not expect a source on the following line, and has the same semantics as the standard delete API. update expects that the partial doc, upsert and script and its options are specified on the next line.

If you’re providing text file input to curl, you must use the --data-binary flag instead of plain -d. The latter doesn’t preserve newlines. Example:

$ cat requests { "index" : { "_index" : "test", "_type" : "type1", "_id" : "1" } } { "field1" : "value1" } $ curl -s -XPOST localhost:9200/_bulk --data-binary "@requests"; echo {"took":7,"items":[{"create":{"_index":"test","_type":"type1","_id":"1","_version":1}}]}

Because this format uses literal n‘s as delimiters, please be sure that the JSON actions and sources are not pretty printed. Here is an example of a correct sequence of bulk commands:

{ "index" : { "_index" : "test", "_type" : "type1", "_id" : "1" } }
{ "field1" : "value1" }
{ "delete" : { "_index" : "test", "_type" : "type1", "_id" : "2" } }
{ "create" : { "_index" : "test", "_type" : "type1", "_id" : "3" } }
{ "field1" : "value3" }
{ "update" : {"_id" : "1", "_type" : "type1", "_index" : "index1"} }
{ "doc" : {"field2" : "value2"} }

Frequently Asked Elasticsearch Interview Questions & Answers

Versioning

Each bulk item can include the version value using the _version/version field. It automatically follows the behavior of the index / delete operation based on the _version mapping. It also support the version_type/_version_type.

Routing

Each bulk item can include the routing value using the _routing/routing field. It automatically follows the behavior of the index / delete operation based on the _routing mapping.

Related Page: The Elasticsearch Nested Type Mapping - Elasticsearch

Parent

Each bulk item can include the parent value using the _parent/parent field. It automatically follows the behavior of the index / delete operation based on the _parent / _routing mapping.

Timestamp

Deprecated in 2.0.0-beta2.
The _timestamp field is deprecated. Instead, use a normal date field and set its value explicitly.
Each bulk item can include the timestamp value using the _timestamp/timestamp field. It automatically follows the behavior of the index operation based on the _timestamp mapping.

TTL

Deprecated in 2.0.0-beta2.
The current _ttl implementation is deprecated and will be replaced with a different implementation in a future version.
Each bulk item can include the ttl value using the _ttl/ttl field. It automatically follows the behavior of the index operation based on the _ttl mapping.

Related Page: Introduction To Elasticsearch Mapping

Write Consistency

When making bulk calls, you can require a minimum number of active shards in the partition through the consistency parameter. The values allowed are one, quorum, and all. 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 are the same).

Refresh

The refresh parameter can be set to true in order to refresh the relevant primary and replica shards immediately after the bulk operation has occurred and make it searchable, instead of waiting for the normal refresh interval to expire. Setting it to true can trigger additional load, and may slow down indexing. Due to its costly nature, the refresh parameter is set on the bulk request level and is not supported on each individual bulk item.

Related Page: Updating Document Using Elasticsearch Update API

Update

When using update action _retry_on_conflict can be used as field in the action itself (not in the extra payload line), to specify how many times an update should be retried in the case of a version conflict.

The update action payload, supports the following options: doc (partial document), upsert, doc_as_upsert, script, params (for script), lang (for script) and fields. Curl example with update actions:

{ "update" : {"_id" : "1", "_type" : "type1", "_index" : "index1", "_retry_on_conflict" : 3} } { "doc" : {"field" : "value"} } { "update" : { "_id" : "0", "_type" : "type1", "_index" : "index1", "_retry_on_conflict" : 3} } { "script" : { "inline": "ctx._source.counter += param1", "lang" : "js", "params" : {"param1" : 1}}, "upsert" : {"counter" : 1}} { "update" : {"_id" : "2", "_type" : "type1", "_index" : "index1", "_retry_on_conflict" : 3} } { "doc" : {"field" : "value"}, "doc_as_upsert" : true } { "update" : {"_id" : "3", "_type" : "type1", "_index" : "index1", "fields" : ["_source"]} } { "doc" : {"field" : "value"} } { "update" : {"_id" : "4", "_type" : "type1", "_index" : "index1"} } { "doc" : {"field" : "value"}, "fields": ["_source"]}

Bulk and cURL

When using cURL the -d flag, which we normally use to send a request body, doesn’t preserve new lines. In order to make requests to the _bulk endpoint, we must instead use the –data-binary flag. Below is a full cURL command for performing the bulk request that we just looked at:
Using cURL to make a bulk request.

curl -XPOST localhost:9200/movies/movie/_bulk?pretty=true --data-binary '
{ "index" : { "_id" : "1" } }
{ "title": "The Godfather", "year": 1972 }
{ "create" : { "_id" : "3" } }
{ "title": "Lawrence of Arabia", "year": 1962 }
{ "delete" : { "_id" : "2" } }
{ "update" : { "_id" : "4" } }
{ "doc": { "year": 1979 }}'

Sense won’t recognize the –data-binary flag when pasting, but it does support performing bulk request. In order to run the above request in Sense we can replace “–data-binary” with “-d” prior to pasting it in Sense.