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Version: 3.8 (unsupported)
    Features and pricing

    ScalarDB SQL Configurations

    This document explains the configurations of ScalarDB SQL.

    ScalarDB SQL offers two connection modes: Direct and Server modes. With Direct mode, ScalarDB SQL client-side library directly uses ScalarDB API. On the other hand, with Server mode, ScalarDB SQL client-side library uses ScalarDB API indirectly through ScalarDB SQL Server.

    There are Direct mode specific configurations and Server mode specific configurations. So we first explain the common configurations, then the Direct mode specific configurations, and the Server mode specific configurations. And lastly, we explain the ScalarDB SQL Server configurations.

    Common configurations​

    The common configurations are as follows:

    namedescriptiondefault
    scalar.db.sql.default_transaction_modeDefault transaction mode. TRANSACTION or TWO_PHASE_COMMIT_TRANSACTION can be set.TRANSACTION
    scalar.db.sql.connection_modeConnection mode. DIRECT or SERVER can be set.DIRECT

    Configurations for Direct mode​

    The configurations for Direct mode are as follows:

    namedescriptiondefault
    scalar.db.sql.statement_cache.enabledEnable the statement cache.false
    scalar.db.sql.statement_cache.sizeThe maximum number of cached statement.100

    Note that in the Direct mode, you need to configure underlining storage/database, as well. Please see Getting Started with ScalarDB for the details of the underlining storage/database configurations.

    Please see also ScalarDB SQL Server for the details of ScalarDB SQL Server.

    Configurations for Server mode​

    The configurations for Server mode are as follows:

    namedescriptiondefault
    scalar.db.sql.server_mode.hostHost name for ScalarDB SQL Server to connect.false
    scalar.db.sql.server_mode.portPort number for ScalarDB SQL Server.60052
    scalar.db.sql.server_mode.deadline_duration_millisa deadline duration (milliseconds) for gRPC connection.60000

    Configurations for ScalarDB SQL Server​

    The configurations for ScalarDB SQL Server are as follows:

    namedescriptiondefault
    scalar.db.sql.server.portPort number for grpc server.60052
    scalar.db.sql.server.prometheus_exporter_portPort number for Prometheus exporter.8080

    Please see also ScalarDB SQL Server for the details of ScalarDB SQL Server.

    Configuration examples​

    Example 1​

    [App (ScalarDB SQL Library)] ---> [underlying storage/database]

    In this setting, App (ScalarDB SQL Library) connects to the underlying storage/database (in this case Cassandra) directly. Note that this setting exists only for development purposes and is not recommended for production use. This is because the App needs to implement scalar-admin interface to take transactionally-consistent backups for ScalarDB, which requires an extra burden for users.

    In this case, an example of configurations in App are as follows:

    #
    # For underlying storage/database configurations
    #

    # Comma separated contact points
    scalar.db.contact_points=<cassandra host>

    # Credential information to access the database
    scalar.db.username=<username>
    scalar.db.password=<password>

    # Storage implementation
    scalar.db.storage=cassandra

    #
    # For ScalarDB SQL
    #

    # Enable the statement cache
    scalar.db.sql.statement_cache.enabled=true

    # The maximum number of cached statement
    scalar.db.sql.statement_cache.size=300

    Example 2​

    [App (ScalarDB SQL Library)] ---> [ScalarDB SQL Server] ---> [ScalarDB Server] ---> [underlying storage/database]

    In this setting, App (ScalarDB SQL Library) connects to an underlying storage/database through ScalarDB SQL Server and ScalarDB Server. This setting is recommended for production use. This is because ScalarDB Server implements scalar-admin interface, which enables you to take transactionally-consistent backups for ScalarDB by pausing the ScalarDB Server.

    Let's assume ScalarDB Server is already set up. Please see ScalarDB server for the details of configurations of ScalarDB Server.

    In this case, an example of configurations for App is as follows:

    #
    # For ScalarDB SQL
    #

    # Connection mode
    scalar.db.sql.connection_mode=SERVER

    # Host name for ScalarDB SQL Server
    scalar.db.sql.server_mode.host=<ScalarDB SQL Server host>

    # Port number for ScalarDB SQL Server
    scalar.db.sql.server_mode.port=<ScalarDB SQL Server port>

    And an example of configurations for ScalarDB SQL Server is as follows:

    #
    # For underlying storage/database configurations
    #

    # Host name for ScalarDB Server
    scalar.db.contact_points=<ScalarDB Server host>

    # Port number for ScalarDB Server
    scalar.db.contact_port=<ScalarDB Server port>

    # Storage implementation
    scalar.db.storage=grpc

    #
    # For ScalarDB SQL
    #

    # Enable the statement cache
    scalar.db.sql.statement_cache.enabled=true

    # The maximum number of cached statement
    scalar.db.sql.statement_cache.size=300