query_service_config

The query_service_config section describes the parameters for YDB to work with external data sources using federated queries.

If access to the required source requires deploying a connector, it must also be configured according to the instructions.

Parameter description

Parameter

Default value

Description

generic.connector.endpoint.host

localhost

Connector host name.

generic.connector.endpoint.port

2130

Connector TCP port.

generic.connector.use_ssl

false

Whether to use connection encryption. When the connector and YDB dynamic node are deployed on the same server, encrypted connection between them is not required, but it can be enabled if needed.

generic.connector.ssl_ca_crt

empty string

Path to the CA certificate used for encryption.

generic.default_settings.name.UsePredicatePushdown

false

Enables predicate pushdown to external data sources: some parts of SQL queries (for example, filters) will be passed for execution to the external source. This can significantly reduce the volume of data transferred over the network from the data source to federated YDB, save its computational resources, and significantly reduce federated query processing time.

available_external_data_sources

empty list

List of allowed external data source types. Applied when all_external_data_sources_are_available: false.

Possible values:

  • ObjectStorage;
  • ClickHouse;
  • PostgreSQL;
  • MySQL;
  • Greenplum;
  • MsSQLServer;
  • Ydb.

all_external_data_sources_are_available

false

Enable all external data source types. When enabled, the available_external_data_sources setting is ignored.

Examples

Enabling ClickHouse and MySQL external sources

query_service_config:
  generic:
    connector:
      endpoint:
        host: localhost                   # host name where the connector is deployed
        port: 2130                        # connector port number
      use_ssl: false                      # flag to enable connection encryption
      ssl_ca_crt: "/opt/ydb/certs/ca.crt" # path to CA certificate
    default_settings:
    - name: UsePredicatePushdown
      value: "true"
  all_external_data_sources_are_available: false
  available_external_data_sources:
  - ClickHouse
  - MySQL

Enabling all external data source types

query_service_config:
  generic:
    connector:
      endpoint:
        host: localhost                   # host name where the connector is deployed
        port: 2130                        # connector port number
      use_ssl: false                      # flag to enable connection encryption
      ssl_ca_crt: "/opt/ydb/certs/ca.crt" # path to CA certificate
    default_settings:
    - name: UsePredicatePushdown
      value: "true"
  all_external_data_sources_are_available: true

See also

Previous
feature_flags
Next
healthcheck_config