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Version: 3.16
Features and pricing

ScalarDB Cluster Configurations

This document describes the configurations for ScalarDB Cluster. ScalarDB Cluster consists of multiple cluster nodes, each of which needs to be configured. The configurations need to be specified in the properties file.

Cluster configurations​

This section describes the configurations for ScalarDB Cluster.

General configurations​

The following general configurations are available for ScalarDB Cluster.

Transaction management configurations​

The following transaction management-related configurations are available for ScalarDB Cluster.

transaction_manager​
  • Field: scalar.db.transaction_manager
  • Description: Transaction manager of ScalarDB. Specify consensus-commit to use Consensus Commit or single-crud-operation to run non-transactional storage operations. Note that the configurations under the scalar.db.consensus_commit prefix are ignored if you use single-crud-operation.
  • Default value: consensus-commit
isolation_level​
  • Field: scalar.db.consensus_commit.isolation_level
  • Description: Isolation level used for Consensus Commit. Either SNAPSHOT, SERIALIZABLE, or READ_COMMITTED can be specified.
  • Default value: SNAPSHOT
coordinator.namespace​
  • Field: scalar.db.consensus_commit.coordinator.namespace
  • Description: Namespace name of Coordinator tables used for Consensus Commit.
  • Default value: coordinator

Node configurations​

The following node-related configurations are available for ScalarDB Cluster.

cluster.membership.type​
  • Field: scalar.db.cluster.membership.type
  • Description: Membership type. Currently, only KUBERNETES can be specified.
  • Default value: KUBERNETES
cluster.membership.kubernetes.endpoint.namespace_name​
  • Field: scalar.db.cluster.membership.kubernetes.endpoint.namespace_name
  • Description: This configuration is for the KUBERNETES membership type. Namespace name for the endpoint resource.
  • Default value: default
cluster.membership.kubernetes.endpoint.name​
  • Field: scalar.db.cluster.membership.kubernetes.endpoint.name
  • Description: This configuration is for the KUBERNETES membership type. Name of the endpoint resource to get the membership info.
  • Default value: empty
cluster.node.decommissioning_duration_secs​
  • Field: scalar.db.cluster.node.decommissioning_duration_secs
  • Description: Duration in seconds until a ScalarDB Cluster node is actually decommissioned when shutting down.
  • Default value: 30
cluster.node.grpc.max_inbound_message_size​
  • Field: scalar.db.cluster.node.grpc.max_inbound_message_size
  • Description: Maximum message size allowed to be received.
  • Default value: The gRPC default value
cluster.node.grpc.max_inbound_metadata_size​
  • Field: scalar.db.cluster.node.grpc.max_inbound_metadata_size
  • Description: Maximum size of metadata allowed to be received.
  • Default value: The gRPC default value
cluster.node.port​
  • Field: scalar.db.cluster.node.port
  • Description: Port number of the ScalarDB Cluster node.
  • Default value: 60053
cluster.node.prometheus_exporter_port​
  • Field: scalar.db.cluster.node.prometheus_exporter_port
  • Description: Port number of the Prometheus exporter.
  • Default value: 9080
cluster.grpc.deadline_duration_millis​
  • Field: scalar.db.cluster.grpc.deadline_duration_millis
  • Description: Deadline duration for gRPC in milliseconds.
  • Default value: 60000 (60 seconds)
cluster.node.standalone_mode.enabled​
  • Field: scalar.db.cluster.node.standalone_mode.enabled
  • Description: Whether standalone mode is enabled. Note that if standalone mode is enabled, the membership configurations (scalar.db.cluster.membership.*) will be ignored.
  • Default value: false
transaction.enabled​
  • Field: scalar.db.transaction.enabled
  • Description: Whether the transaction feature is enabled. For example, if you use only the embedding feature, you can set this property to false.
  • Default value: true
cluster.node.scanner_management.expiration_time_millis​
  • Field: scalar.db.cluster.node.scanner_management.expiration_time_millis
  • Description: ScalarDB Cluster nodes maintain in-progress scanners. This process expires scanners that have been idle for an extended period to prevent resource leaks. This configuration specifies the expiration time of this scanner management feature in milliseconds.
  • Default value: 60000 (60 seconds)

The following performance-related configurations are available for the Consensus Commit transaction manager.

parallel_executor_count​

  • Field: scalar.db.consensus_commit.parallel_executor_count
  • Description: Number of executors (threads) for parallel execution. This number refers to the total number of threads across transactions in a ScalarDB Cluster node or a ScalarDB Core process.
  • Default value: 128

parallel_preparation.enabled​

  • Field: scalar.db.consensus_commit.parallel_preparation.enabled
  • Description: Whether or not the preparation phase is executed in parallel.
  • Default value: true

parallel_validation.enabled​

  • Field: scalar.db.consensus_commit.parallel_validation.enabled
  • Description: Whether or not the validation phase (in EXTRA_READ) is executed in parallel.
  • Default value: The value of scalar.db.consensus_commit.parallel_commit.enabled

parallel_commit.enabled​

  • Field: scalar.db.consensus_commit.parallel_commit.enabled
  • Description: Whether or not the commit phase is executed in parallel.
  • Default value: true

parallel_rollback.enabled​

  • Field: scalar.db.consensus_commit.parallel_rollback.enabled
  • Description: Whether or not the rollback phase is executed in parallel.
  • Default value: The value of scalar.db.consensus_commit.parallel_commit.enabled

async_commit.enabled​

  • Field: scalar.db.consensus_commit.async_commit.enabled
  • Description: Whether or not the commit phase is executed asynchronously.
  • Default value: false

async_rollback.enabled​

  • Field: scalar.db.consensus_commit.async_rollback.enabled
  • Description: Whether or not the rollback phase is executed asynchronously.
  • Default value: The value of scalar.db.consensus_commit.async_commit.enabled

parallel_implicit_pre_read.enabled​

  • Field: scalar.db.consensus_commit.parallel_implicit_pre_read.enabled
  • Description: Whether or not implicit pre-read is executed in parallel.
  • Default value: true

one_phase_commit.enabled​

  • Field: scalar.db.consensus_commit.one_phase_commit.enabled
  • Description: Whether or not the one-phase commit optimization is enabled.
  • Default value: false

coordinator.write_omission_on_read_only.enabled​

  • Field: scalar.db.consensus_commit.coordinator.write_omission_on_read_only.enabled
  • Description: Whether or not the Coordinator write omission optimization is enabled for read-only transactions. This optimization is useful for read-only transactions that do not modify any data, as it avoids unnecessary writes to the Coordinator tables.
  • Default value: true

coordinator.group_commit.enabled​

  • Field: scalar.db.consensus_commit.coordinator.group_commit.enabled
  • Description: Whether or not committing the transaction state is executed in batch mode. This feature can't be used with a two-phase commit interface.
  • Default value: false

coordinator.group_commit.slot_capacity​

  • Field: scalar.db.consensus_commit.coordinator.group_commit.slot_capacity
  • Description: Maximum number of slots in a group for the group commit feature. A large value improves the efficiency of group commit, but may also increase latency and the likelihood of transaction conflicts.1
  • Default value: 20

coordinator.group_commit.group_size_fix_timeout_millis​

  • Field: scalar.db.consensus_commit.coordinator.group_commit.group_size_fix_timeout_millis
  • Description: Timeout to fix the size of slots in a group. A large value improves the efficiency of group commit, but may also increase latency and the likelihood of transaction conflicts.1
  • Default value: 40

coordinator.group_commit.delayed_slot_move_timeout_millis​

  • Field: scalar.db.consensus_commit.coordinator.group_commit.delayed_slot_move_timeout_millis
  • Description: Timeout to move delayed slots from a group to another isolated group to prevent the original group from being affected by delayed transactions. A large value improves the efficiency of group commit, but may also increase the latency and the likelihood of transaction conflicts.1
  • Default value: 1200

coordinator.group_commit.old_group_abort_timeout_millis​

  • Field: scalar.db.consensus_commit.coordinator.group_commit.old_group_abort_timeout_millis
  • Description: Timeout to abort an old ongoing group. A small value reduces resource consumption through aggressive aborts, but may also increase the likelihood of unnecessary aborts for long-running transactions.
  • Default value: 60000

coordinator.group_commit.timeout_check_interval_millis​

  • Field: scalar.db.consensus_commit.coordinator.group_commit.timeout_check_interval_millis
  • Description: Interval for checking the group commit–related timeouts.
  • Default value: 20

coordinator.group_commit.metrics_monitor_log_enabled​

  • Field: scalar.db.consensus_commit.coordinator.group_commit.metrics_monitor_log_enabled
  • Description: Whether or not the metrics of the group commit are logged periodically.
  • Default value: false

ScalarDB has a storage (database) abstraction layer that supports multiple storage implementations. You can specify the storage implementation by using the scalar.db.storage property.

note

For details about using multiple storages, see Multi-storage configurations.

Select a database to see the configurations available for each storage.

The following configurations are available for JDBC databases.

storage

  • Field: scalar.db.storage
  • Description: jdbc must be specified.

contact_points

  • Field: scalar.db.contact_points
  • Description: JDBC connection URL.
  • Default value: empty

username

  • Field: scalar.db.username
  • Description: Username to access the database.
  • Default value: empty

password

  • Field: scalar.db.password
  • Description: Password to access the database.
  • Default value: empty

jdbc.connection_pool.min_idle

  • Field: scalar.db.jdbc.connection_pool.min_idle
  • Description: Minimum number of idle connections in the connection pool.
  • Default value: 20

jdbc.connection_pool.max_idle

  • Field: scalar.db.jdbc.connection_pool.max_idle
  • Description: Maximum number of connections that can remain idle in the connection pool.
  • Default value: 50

jdbc.connection_pool.max_total

  • Field: scalar.db.jdbc.connection_pool.max_total
  • Description: Maximum total number of idle and borrowed connections that can be active at the same time for the connection pool. Use a negative value for no limit.
  • Default value: 200

jdbc.prepared_statements_pool.enabled

  • Field: scalar.db.jdbc.prepared_statements_pool.enabled
  • Description: Setting this property to true enables prepared-statement pooling.
  • Default value: false

jdbc.prepared_statements_pool.max_open

  • Field: scalar.db.jdbc.prepared_statements_pool.max_open
  • Description: Maximum number of open statements that can be allocated from the statement pool at the same time. Use a negative value for no limit.
  • Default value: -1

jdbc.isolation_level

  • Field: scalar.db.jdbc.isolation_level
  • Description: Isolation level for JDBC. READ_COMMITTED, REPEATABLE_READ, or SERIALIZABLE can be specified.
  • Default value: Underlying-database specific

jdbc.table_metadata.connection_pool.min_idle

  • Field: scalar.db.jdbc.table_metadata.connection_pool.min_idle
  • Description: Minimum number of idle connections in the connection pool for the table metadata.
  • Default value: 5

jdbc.table_metadata.connection_pool.max_idle

  • Field: scalar.db.jdbc.table_metadata.connection_pool.max_idle
  • Description: Maximum number of connections that can remain idle in the connection pool for the table metadata.
  • Default value: 10

jdbc.table_metadata.connection_pool.max_total

  • Field: scalar.db.jdbc.table_metadata.connection_pool.max_total
  • Description: Maximum total number of idle and borrowed connections that can be active at the same time for the connection pool for the table metadata. Use a negative value for no limit.
  • Default value: 25

jdbc.admin.connection_pool.min_idle

  • Field: scalar.db.jdbc.admin.connection_pool.min_idle
  • Description: Minimum number of idle connections in the connection pool for admin.
  • Default value: 5

jdbc.admin.connection_pool.max_idle

  • Field: scalar.db.jdbc.admin.connection_pool.max_idle
  • Description: Maximum number of connections that can remain idle in the connection pool for admin.
  • Default value: 10

jdbc.admin.connection_pool.max_total

  • Field: scalar.db.jdbc.admin.connection_pool.max_total
  • Description: Maximum total number of idle and borrowed connections that can be active at the same time for the connection pool for admin. Use a negative value for no limit.
  • Default value: 25

jdbc.db2.variable_key_column_size

  • Field: scalar.db.jdbc.db2.variable_key_column_size
  • Description: Column size for TEXT and BLOB columns in IBM Db2 when they are used as a primary key or secondary key. Minimum 64 bytes.
  • Default value: 128

jdbc.db2.time_column.default_date_component

  • Field: scalar.db.jdbc.db2.time_column.default_date_component
  • Description: Value of the date component used for storing TIME data in IBM Db2. Since the IBM Db2 TIMESTAMP type is used to store ScalarDB TIME type data because it provides fractional-second precision, ScalarDB stores TIME data with the same date component value for ease of comparison and sorting.
  • Default value: 1970-01-01
note

If you're using SQLite3 as a JDBC database, you must set scalar.db.contact_points as follows:

scalar.db.contact_points=jdbc:sqlite:<SQLITE_DB_FILE_PATH>?busy_timeout=10000

Unlike other JDBC databases, SQLite3 doesn't fully support concurrent access. To avoid frequent errors caused internally by SQLITE_BUSY, we recommend setting a busy_timeout parameter.

Multi-storage configurations​

ScalarDB supports using multiple storage implementations simultaneously. For details about using multiple storages, see Multi-Storage Transactions.

storage​
  • Field: scalar.db.storage
  • Description: multi-storage must be specified.
multi_storage.storages​
  • Field: scalar.db.multi_storage.storages
  • Description: Comma-separated storage names (for example, cassandra,mysql). These storage names will be used in the scalar.db.multi_storage.namespace_mapping property to map namespaces to storages.
  • Default value: empty
multi_storage.default_storage​
  • Field: scalar.db.multi_storage.default_storage
  • Description: Default storage name. This storage will be used for any namespace that doesn't have mapping defined in the scalar.db.multi_storage.namespace_mapping property.
  • Default value: empty
multi_storage.namespace_mapping​
  • Field: scalar.db.multi_storage.namespace_mapping
  • Description: Mapping of namespaces to storages (for example, user:my_cassandra,coordinator:my_mysql).
  • Default value: empty
tip

The storage names (<STORAGE_NAME_FOR_NAMESPACE>) are arbitrary values that you need to define. You can use any names that you like as long as they are consistent across the multi-storage configurations.

multi_storage.storages.<STORAGE_NAME_FOR_NAMESPACE>.<PROPERTY_NAME>​

For configuring specific storages, use scalar.db.multi_storage.storages.<STORAGE_NAME_FOR_NAMESPACE>.<PROPERTY_NAME>, with <STORAGE_NAME_FOR_NAMESPACE> being one of the storage names specified in the scalar.db.multi_storage.storages property and <PROPERTY_NAME> being the property name for the specific storage.

For example, if you've defined namespace mapping as scalar.db.multi_storage.namespace_mapping=user:my_cassandra,coordinator:my_mysql, with my_cassandra and my_mysql being the storage names for the user and coordinator namespaces, respectively:

  • You can specify the contact points for Cassandra by using scalar.db.multi_storage.storages.my_cassandra.contact_points.
  • You can specify the max idle time for the connection pool settings for MySQL by using scalar.db.multi_storage.storages.my_mysql.jdbc.connection_pool.max_idle.

For details about the properties available for each storage, see Storage-related configurations.

Cross-partition scan configurations​

By enabling the cross-partition scan option as described below, the Scan operation can retrieve all records across partitions. In addition, you can specify arbitrary conditions and orderings in the cross-partition Scan operation by enabling cross_partition_scan.filtering and cross_partition_scan.ordering, respectively. Currently, the cross-partition scan with ordering option is available only for JDBC databases. To enable filtering and ordering, scalar.db.cross_partition_scan.enabled must be set to true.

For details on how to use cross-partition scan, see Scan operation.

warning

For non-JDBC databases, we do not recommend enabling cross-partition scan with the SERIALIAZABLE isolation level because transactions could be executed at a lower isolation level (that is, SNAPSHOT). When using non-JDBC databases, use cross-partition scan at your own risk only if consistency does not matter for your transactions.

cross_partition_scan.enabled​
  • Field: scalar.db.cross_partition_scan.enabled
  • Description: Enable cross-partition scan.
  • Default value: false
cross_partition_scan.filtering.enabled​
  • Field: scalar.db.cross_partition_scan.filtering.enabled
  • Description: Enable filtering in cross-partition scan.
  • Default value: false
cross_partition_scan.ordering.enabled​
  • Field: scalar.db.cross_partition_scan.ordering.enabled
  • Description: Enable ordering in cross-partition scan.
  • Default value: false

Scan configurations​

You can configure the fetch size for storage scan operations by using the following property.

scan_fetch_size​
  • Field: scalar.db.scan_fetch_size
  • Description: Specifies the number of records to fetch in a single batch during a storage scan operation. A larger value can improve performance for a large result set by reducing round trips to the storage, but it also increases memory usage. A smaller value uses less memory but may increase latency.
  • Default value: 10

The configurations for ScalarDB Cluster GraphQL are as follows:

graphql.enabled​

  • Field: scalar.db.graphql.enabled
  • Description: Whether ScalarDB Cluster GraphQL is enabled.
  • Default value: false

graphql.port​

  • Field: scalar.db.graphql.port
  • Description: Port number of the GraphQL server.
  • Default value: 8080

graphql.path​

  • Field: scalar.db.graphql.path
  • Description: Path component of the URL of the GraphQL endpoint.
  • Default value: /graphql

graphql.namespaces​

  • Field: scalar.db.graphql.namespaces
  • Description: Comma-separated list of namespaces of tables for which the GraphQL server generates a schema. If not specified, the GraphQL server generates a schema for all tables in all ScalarDB-managed namespaces.
  • Default value: empty

graphql.graphiql​

  • Field: scalar.db.graphql.graphiql
  • Description: Whether the GraphQL server serves GraphiQL IDE.
  • Default value: true

graphql.schema_checking_interval_millis​

  • Field: scalar.db.graphql.schema_checking_interval_millis
  • Description: Interval in milliseconds at which GraphQL server will rebuild the GraphQL schema if any change is detected in the ScalarDB schema.
  • Default value: 30000 (30 seconds)

Creating or modifying the ScalarDB schema when the server is running​

Since the GraphQL schema is statically built at server startup, if the ScalarDB schema is modified (for example, if a table is added, altered, or deleted), then the corresponding GraphQL schema won't reflect the changes unless it is rebuilt. To address this, the GraphQL server provides two mechanisms: a periodic check and an on-demand check.

Run periodic checks​

The server periodically checks if changes in the ScalarDB schema occur and rebuilds the corresponding GraphQL schema if necessary. By default, the check occurs every 30 seconds, but the interval can be configured by using the scalar.db.graphql.schema_checking_interval_millis property.

If you don't need to run periodic checks, you can disable it by setting the property value to -1.

Run on-demand checks​

You can also request the server to check changes in the ScalarDB schema and rebuild the corresponding GraphQL schema if necessary by performing a POST request to the /update-graphql-schema endpoint of the HTTP API.

For example, if the HTTP API is running on localhost:8080 and the scalar.db.graphql.path property is set to /graphql, this endpoint can be called by running the following command:

curl -X POST http://localhost:8080/graphql/update-graphql-schema

The configurations for ScalarDB Cluster SQL are as follows:

sql.enabled​

  • Field: scalar.db.sql.enabled
  • Description: Whether ScalarDB Cluster SQL is enabled.
  • Default value: false

sql.statement_cache.enabled​

  • Field: scalar.db.sql.statement_cache.enabled
  • Description: Enable the statement cache.
  • Default value: false

sql.statement_cache.size​

  • Field: scalar.db.sql.statement_cache.size
  • Description: Maximum number of cached statements.
  • Default value: 100

sql.default_transaction_mode​

  • Field: scalar.db.sql.default_transaction_mode
  • Description: Default transaction mode. TRANSACTION or TWO_PHASE_COMMIT_TRANSACTION can be set.
  • Default value: TRANSACTION

sql.default_namespace_name​

  • Field: scalar.db.sql.default_namespace_name
  • Description: Default namespace name. If you don't specify a namespace name in your SQL statement, this value is used.
  • Default value: empty

ABAC configurations​

The following shows the attribute-based access control (ABAC) configurations for ScalarDB Cluster.

warning

The single CRUD operation transaction manager does not support ABAC.

abac.enabled​

  • Field: scalar.db.cluster.abac.enabled
  • Description: Whether the ABAC feature is enabled.
  • Default value: false
warning

If you enable the ABAC feature, you will also need to do the following:

abac.cache_expiration_time_millis​

  • Field: scalar.db.cluster.abac.cache_expiration_time_millis
  • Description: The cache expiration time of the ABAC metadata cache in milliseconds. If you update the ABAC metadata, for example, the policy configuration, you might need to wait until this expiration time is reached for the changes to be applied. Setting this property to a low number may increase the number of accesses to the backend database and decrease performance.
  • Default value: 60000 (1 minute)

Other ScalarDB Cluster configurations​

The following are additional configurations available for ScalarDB Cluster.

metadata.cache_expiration_time_secs​

  • Field: scalar.db.metadata.cache_expiration_time_secs
  • Description: ScalarDB has a metadata cache to reduce the number of requests to the database. This setting specifies the expiration time of the cache in seconds. If you specify -1, the cache will never expire.
  • Default value: 60

active_transaction_management.expiration_time_millis​

  • Field: scalar.db.active_transaction_management.expiration_time_millis
  • Description: ScalarDB maintains in-progress transactions, which can be resumed by using a transaction ID. This process expires transactions that have been idle for an extended period to prevent resource leaks. This setting specifies the expiration time of this transaction management feature in milliseconds.
  • Default value: 60000 (60 seconds)

consensus_commit.include_metadata.enabled​

  • Field: scalar.db.consensus_commit.include_metadata.enabled
  • Description: When using Consensus Commit, if this is set to true, Get and Scan operations results will contain transaction metadata. To see the transaction metadata columns details for a given table, you can use the DistributedTransactionAdmin.getTableMetadata() method, which will return the table metadata augmented with the transaction metadata columns. Using this configuration can be useful to investigate transaction-related issues.
  • Default value: false

default_namespace_name​

  • Field: scalar.db.default_namespace_name
  • Description: The given namespace name will be used by operations that do not already specify a namespace.
  • Default value: empty

Client configurations​

This section describes the general configurations for the ScalarDB Cluster client.

Configurations for the primitive interface​

The following shows the general configurations for the ScalarDB Cluster client.

transaction_manager​

  • Field: scalar.db.transaction_manager
  • Description: cluster should be specified.
  • Default value: empty

contact_points​

  • Field: scalar.db.contact_points
  • Description: Contact point of the cluster. If you use the indirect client mode, specify the IP address of the load balancer in front of your cluster nodes by using the format indirect:<the load balancer IP address>. If you use the direct-kubernetes client mode, specify the namespace name (optional) and the name of the endpoint resource to get the membership information by using the format direct-kubernetes:<namespace name>/<endpoint name> or just direct-kubernetes:<endpoint name>. If you don't specify the namespace name, the client will use the default namespace.
  • Default value: empty

contact_port​

  • Field: scalar.db.contact_port
  • Description: Port number for the contact point.
  • Default value: 60053

cluster.grpc.deadline_duration_millis​

  • Field: scalar.db.cluster.grpc.deadline_duration_millis
  • Description: Deadline duration for gRPC in millis.
  • Default value: 60000 (60 seconds)

cluster.grpc.max_inbound_message_size​

  • Field: scalar.db.cluster.grpc.max_inbound_message_size
  • Description: Maximum message size allowed for a single gRPC frame.
  • Default value: The gRPC default value

cluster.grpc.max_inbound_metadata_size​

  • Field: scalar.db.cluster.grpc.max_inbound_metadata_size
  • Description: Maximum size of metadata allowed to be received.
  • Default value: The gRPC default value

cluster.client.scan_fetch_size​

  • Field: scalar.db.cluster.client.scan_fetch_size
  • Description: The fetch size used for Scanner to fetch data from the cluster. This is the number of records that Scanner fetches at once from the cluster. A larger value can improve performance by reducing the number of round trips to the cluster, but it may also increase memory usage.
  • Default value: 10

For example, if you use the indirect client mode and the load balancer IP address is 192.168.10.1, you can configure the client as follows:

scalar.db.transaction_manager=cluster
scalar.db.contact_points=indirect:192.168.10.1

Or if you use the direct-kubernetes client mode, with the namespace of the endpoint as ns and the endpoint name as scalardb-cluster, you can configure the client as follows:

scalar.db.transaction_manager=cluster
scalar.db.contact_points=direct-kubernetes:ns/scalardb-cluster

Configurations for the SQL interface​

The following shows the configurations for the ScalarDB Cluster SQL client.

sql.connection_mode​

  • Field: scalar.db.sql.connection_mode
  • Description: cluster should be specified.
  • Default value: empty

sql.cluster_mode.contact_points​

  • Field: scalar.db.sql.cluster_mode.contact_points
  • Description: Contact point of the cluster. If you use the indirect client mode, specify the IP address of the load balancer in front of your cluster nodes by using the format indirect:<the load balancer IP address>. If you use the direct-kubernetes client mode, specify the namespace name (optional) and the name of the endpoint resource to get the membership information by using the format direct-kubernetes:<namespace name>/<endpoint name> or just direct-kubernetes:<endpoint name>. If you don't specify the namespace name, the client will use the default namespace.
  • Default value: empty

sql.cluster_mode.contact_port​

  • Field: scalar.db.sql.cluster_mode.contact_port
  • Description: Port number for the contact point.
  • Default value: 60053

sql.default_transaction_mode​

  • Field: scalar.db.sql.default_transaction_mode
  • Description: Default transaction mode. TRANSACTION or TWO_PHASE_COMMIT_TRANSACTION can be set.
  • Default value: TRANSACTION

sql.default_namespace_name​

  • Field: scalar.db.sql.default_namespace_name
  • Description: Default namespace name. If you don't specify a namespace name in your SQL statement, this value is used.
  • Default value: empty

cluster.grpc.deadline_duration_millis​

  • Field: scalar.db.cluster.grpc.deadline_duration_millis
  • Description: Deadline duration for gRPC in millis.
  • Default value: 60000 (60 seconds)

cluster.grpc.max_inbound_message_size​

  • Field: scalar.db.cluster.grpc.max_inbound_message_size
  • Description: Maximum message size allowed for a single gRPC frame.
  • Default value: The gRPC default value

cluster.grpc.max_inbound_metadata_size​

  • Field: scalar.db.cluster.grpc.max_inbound_metadata_size
  • Description: Maximum size of metadata allowed to be received.
  • Default value: The gRPC default value

For example, if you use the indirect client mode and the load balancer IP address is 192.168.10.1, you can configure the client as follows:

scalar.db.sql.connection_mode=cluster
scalar.db.sql.cluster_mode.contact_points=indirect:192.168.10.1

Or if you use the direct-kubernetes client mode, with the namespace of the endpoint as ns and the endpoint name as scalardb-cluster, you can configure the client as follows:

scalar.db.sql.connection_mode=cluster
scalar.db.sql.cluster_mode.contact_points=direct-kubernetes:ns/scalardb-cluster

For details about how to configure ScalarDB JDBC, see JDBC connection URL.

For details about how to configure Spring Data JDBC for ScalarDB, see Configurations.

Configuration example - App, ScalarDB Cluster, and database​

In this example configuration, the app (ScalarDB library with gRPC) connects to an underlying storage or database (in this case, Cassandra) through ScalarDB Cluster, which is a component that is available only in the ScalarDB Enterprise edition.

note

This configuration is acceptable for production use because ScalarDB Cluster implements the Scalar Admin interface, which enables you to take transactionally consistent backups for ScalarDB by pausing ScalarDB Cluster.

The following is an example of the configuration for connecting the app to the underlying database through ScalarDB Cluster:

# Transaction manager implementation.
scalar.db.transaction_manager=cluster

# Contact point of the cluster.
scalar.db.contact_points=indirect:<SCALARDB_CLUSTER_CONTACT_POINT>

For details about client configurations, see the ScalarDB Cluster client configurations.

Footnotes​

  1. It's worth benchmarking the performance with a few variations (for example, 75% and 125% of the default value) on the same underlying storage that your application uses, considering your application's access pattern, to determine the optimal configuration as it really depends on those factors. Also, it's important to benchmark combinations of these parameters (for example, first, slot_capacity:20 and group_size_fix_timeout_millis:40; second, slot_capacity:30 and group_size_fix_timeout_millis:40; and third, slot_capacity:20 and group_size_fix_timeout_millis:80) to determine the optimal combination. ↩ ↩2 ↩3