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Version: 1.12.0



The Elasticsearch Load Node allows for writing into an index of the Elasticsearch engine. This document describes how to setup the Elasticsearch Load Node to run SQL queries against Elasticsearch.

The Load Node can operate in upsert mode for exchanging UPDATE/DELETE messages with the external system using the primary key defined on the DDL.

If no primary key is defined on the DDL, the Load Node can only operate in append mode for exchanging INSERT only messages with external system.

Supported Version

Load NodeVersion
elasticsearchElasticsearch: 5.x, 6.x, 7.x


In order to use the Elasticsearch Load Node the following dependencies are required for both projects using a build automation tool (such as Maven or SBT) and SQL Client with Sort Connectors JAR bundles.

  • Elasticsearch 6
  • Elasticsearch 7

How to create an Elasticsearch Load Node

Usage for SQL API

The example below shows how to create an Elasticsearch Load Node with Flink SQL :

CREATE TABLE myUserTable (
user_id STRING,
user_name STRING,
) WITH (
'connector' = 'elasticsearch-7-inlong',
'hosts' = 'http://localhost:9200',
'index' = 'users'

Usage for InLong Dashboard

TODO: It will be supported in the future.

Usage for InLong Manager Client

TODO: It will be supported in the future.

Elasticsearch Load Node Options

connectorrequired(none)StringSpecify what connector to use, valid values are:

- elasticsearch-6-inlong: connect to Elasticsearch 5.x and 6.x cluster.
- elasticsearch-7-inlong: connect to Elasticsearch 7.x and later versions cluster.
hostsrequired(none)StringOne or more Elasticsearch hosts to connect to, e.g. 'http://host_name:9092;http://host_name:9093'.
indexrequired(none)StringElasticsearch index for every record. Can be a static index (e.g. 'myIndex') or a dynamic index (e.g. 'index-\{log_ts\|yyyy-MM-dd}'). See the following Dynamic Index section for more details.
document-typerequired in 5.x and 6.x(none)StringElasticsearch document type. Not necessary anymore in elasticsearch-7.
document-id.key-delimiteroptional_StringDelimiter for composite keys ("_" by default), e.g., "$" would result in IDs "KEY1\$KEY2\$KEY3".
usernameoptional(none)StringUsername used to connect to Elasticsearch instance. Please notice that Elasticsearch doesn't pre-bundled security feature, but you can enable it by following the guideline to secure an Elasticsearch cluster.
passwordoptional(none)StringPassword used to connect to Elasticsearch instance. If username is configured, this option must be configured with non-empty string as well.
failure-handleroptionalfailStringFailure handling strategy in case a request to Elasticsearch fails. Valid strategies are:

- fail: throws an exception if a request fails and thus causes a job failure.
- ignore: ignores failures and drops the request.
- retry-rejected: re-adds requests that have failed due to queue capacity saturation.
- custom class name: for failure handling with a ActionRequestFailureHandler subclass.
sink.flush-on-checkpointoptionaltrueBooleanFlush on checkpoint or not. When disabled, a sink will not wait for all pending action requests to be acknowledged by Elasticsearch on checkpoints. Thus, a sink does NOT provide any strong guarantees for at-least-once delivery of action requests.
sink.bulk-flush.max-actionsoptional1000IntegerMaximum number of buffered actions per bulk request. Can be set to '0' to disable it.
sink.bulk-flush.max-sizeoptional2mbMemorySizeMaximum size in memory of buffered actions per bulk request. Must be in MB granularity. Can be set to '0' to disable it.
sink.bulk-flush.intervaloptional1sDurationThe interval to flush buffered actions. Can be set to '0' to disable it. Note, both 'sink.bulk-flush.max-size' and 'sink.bulk-flush.max-actions'can be set to '0' with the flush interval set allowing for complete async processing of buffered actions.
sink.bulk-flush.backoff.strategyoptionalDISABLEDStringSpecify how to perform retries if any flush actions failed due to a temporary request error. Valid strategies are:

- DISABLED: no retry performed, i.e. fail after the first request error.
- CONSTANT: wait for backoff delay between retries.
- EXPONENTIAL: initially wait for backoff delay and increase exponentially between retries.
sink.bulk-flush.backoff.max-retriesoptional8IntegerMaximum number of backoff retries.
sink.bulk-flush.backoff.delayoptional50msDurationDelay between each backoff attempt. For CONSTANT backoff, this is simply the delay between each retry. For EXPONENTIAL backoff, this is the initial base delay.
connection.max-retry-timeoutoptional(none)DurationMaximum timeout between retries.
connection.path-prefixoptional(none)StringPrefix string to be added to every REST communication, e.g., '/v1'.
routing.filed-nameoptional(none)StringUsing field value in the record to dynamically generate routing filed.
formatoptionaljsonStringElasticsearch connector supports to specify a format. The format must produce a valid json document. By default uses built-in 'json' format. Please refer to JSON Format page for more details.
inlong.metric.labelsoptional(none)StringInlong metric label, format of value is groupId=[groupId]&streamId=[streamId]&nodeId=[nodeId].


Key Handling

Elasticsearch sink can work in either upsert mode or append mode, it depends on whether primary key is defined. If primary key is defined, Elasticsearch sink works in upsert mode which can consume queries containing UPDATE/DELETE messages. If primary key is not defined, Elasticsearch sink works in append mode which can only consume queries containing INSERT only messages.

In Elasticsearch connector, the primary key is used to calculate the Elasticsearch document id, which is a string of up to 512 bytes. It cannot have whitespaces. The Elasticsearch connector generates a document ID string for every row by concatenating all primary key fields in the order defined in the DDL using a key delimiter specified by document-id.key-delimiter. Certain types are not allowed as primary key field as they do not have a good string representation, e.g. BYTES, ROW, ARRAY, MAP, etc. If no primary key is specified, Elasticsearch will generate a document id automatically.

See CREATE TABLE DDL for more details about PRIMARY KEY syntax.

Dynamic Index

Elasticsearch Load Node supports both static index and dynamic index.

If you want to have a static index, the index option value should be a plain string, e.g. 'myusers', all the records will be consistently written into "myusers" index.

If you want to have a dynamic index, you can use {field_name} to reference a field value in the record to dynamically generate a target index. You can also use '{field_name|date_format_string}' to convert a field value of TIMESTAMP/DATE/TIME type into the format specified by the date_format_string. The date_format_string is compatible with Java's DateTimeFormatter. For example, if the option value is 'myusers-{'{log_ts|yyyy-MM-dd}'}', then a record with log_ts field value 2020-03-27 12:25:55 will be written into "myusers-2020-03-27" index.

Data Type Mapping

JSON typeFlink SQL type
string with encoding: base64BINARY / VARBINARY
string with format: dateDATE
string with format: timeTIME
string with format: date-timeTIMESTAMP
string with format: date-time (with UTC time zone)TIMESTAMP_WITH_LOCAL_TIME_ZONE