Version: 3.16

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.

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

JDBC databases
DynamoDB
Cosmos DB for NoSQL
Cassandra

The following configurations are available for JDBC databases.

`storage`

Field: scalar.db.storage
Description: jdbc must be specified.
Default value: empty

`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: 100

`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.

The following configurations are available for DynamoDB.

`storage`

Field: scalar.db.storage
Description: dynamo must be specified.
Default value: empty

`contact_points`

Field: scalar.db.contact_points
Description: AWS region with which ScalarDB should communicate (for example, us-east-1).
Default value: empty

`username`

Field: scalar.db.username
Description: AWS access key used to identify the user interacting with AWS.
Default value: empty

`password`

Field: scalar.db.password
Description: AWS secret access key used to authenticate the user interacting with AWS.
Default value: empty

`dynamo.endpoint_override`

Field: scalar.db.dynamo.endpoint_override
Description: Amazon DynamoDB endpoint with which ScalarDB should communicate. This is primarily used for testing with a local instance instead of an AWS service.
Default value: empty

`dynamo.namespace.prefix`

Field: scalar.db.dynamo.namespace.prefix
Description: Prefix for the user namespaces and metadata namespace names. Since AWS requires having unique tables names in a single AWS region, this is useful if you want to use multiple ScalarDB environments (development, production, etc.) in a single AWS region.
Default value: empty

The following configurations are available for Cosmos DB for NoSQL.

`storage`

Field: scalar.db.storage
Description: cosmos must be specified.
Default value: empty

`contact_points`

Field: scalar.db.contact_points
Description: Azure Cosmos DB for NoSQL endpoint with which ScalarDB should communicate.
Default value: empty

`password`

Field: scalar.db.password
Description: Either a master or read-only key used to perform authentication for accessing Azure Cosmos DB for NoSQL.
Default value: empty

`cosmos.consistency_level`

Field: scalar.db.cosmos.consistency_level
Description: Consistency level used for Cosmos DB operations. STRONG or BOUNDED_STALENESS can be specified.
Default value: STRONG

The following configurations are available for Cassandra.

`storage`

Field: scalar.db.storage
Description: cassandra must be specified.
Default value: empty

`contact_points`

Field: scalar.db.contact_points
Description: Comma-separated contact points.
Default value: empty

`contact_port`

Field: scalar.db.contact_port
Description: Port number for all the contact points.
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

Multi-storage support

ScalarDB supports using multiple storage implementations simultaneously. You can use multiple storages by specifying multi-storage as the value for the scalar.db.storage property.

For details about using multiple storages, see Multi-Storage Transactions.

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 fetch size

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

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.

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

Cluster configurations​

General configurations​

Transaction management configurations​

transaction_manager​

isolation_level​

coordinator.namespace​

Node configurations​

cluster.membership.type​

cluster.membership.kubernetes.endpoint.namespace_name​

cluster.membership.kubernetes.endpoint.name​

cluster.node.decommissioning_duration_secs​

cluster.node.grpc.max_inbound_message_size​

cluster.node.grpc.max_inbound_metadata_size​

cluster.node.port​

cluster.node.prometheus_exporter_port​

cluster.grpc.deadline_duration_millis​

cluster.node.standalone_mode.enabled​

transaction.enabled​

cluster.node.scanner_management.expiration_time_millis​

Performance-related configurations​

parallel_executor_count​

parallel_preparation.enabled​

parallel_validation.enabled​

parallel_commit.enabled​

parallel_rollback.enabled​

async_commit.enabled​

async_rollback.enabled​

parallel_implicit_pre_read.enabled​

one_phase_commit.enabled​

coordinator.write_omission_on_read_only.enabled​

coordinator.group_commit.enabled​

coordinator.group_commit.slot_capacity​

coordinator.group_commit.group_size_fix_timeout_millis​

coordinator.group_commit.delayed_slot_move_timeout_millis​

coordinator.group_commit.old_group_abort_timeout_millis​

coordinator.group_commit.timeout_check_interval_millis​

coordinator.group_commit.metrics_monitor_log_enabled​

Storage-related configurations​

storage

contact_points

username

password

jdbc.connection_pool.min_idle

jdbc.connection_pool.max_idle

jdbc.connection_pool.max_total

jdbc.prepared_statements_pool.enabled

jdbc.prepared_statements_pool.max_open

jdbc.isolation_level

jdbc.table_metadata.connection_pool.min_idle

jdbc.table_metadata.connection_pool.max_idle

jdbc.table_metadata.connection_pool.max_total

jdbc.admin.connection_pool.min_idle

jdbc.admin.connection_pool.max_idle

jdbc.admin.connection_pool.max_total

jdbc.db2.variable_key_column_size

jdbc.db2.time_column.default_date_component

storage

contact_points

username

password

dynamo.endpoint_override

dynamo.namespace.prefix

storage

contact_points

password

cosmos.consistency_level

storage

contact_points

contact_port

username

password

Multi-storage support​

Cross-partition scan configurations​

cross_partition_scan.enabled​

cross_partition_scan.filtering.enabled​

cross_partition_scan.ordering.enabled​

Scan fetch size​

scan_fetch_size​

GraphQL-related configurations​

graphql.enabled​

Cluster configurations

General configurations

Transaction management configurations

`transaction_manager`

`isolation_level`

`coordinator.namespace`

Node configurations

`cluster.membership.type`

`cluster.membership.kubernetes.endpoint.namespace_name`

`cluster.membership.kubernetes.endpoint.name`

`cluster.node.decommissioning_duration_secs`

`cluster.node.grpc.max_inbound_message_size`

`cluster.node.grpc.max_inbound_metadata_size`

`cluster.node.port`

`cluster.node.prometheus_exporter_port`

`cluster.grpc.deadline_duration_millis`

`cluster.node.standalone_mode.enabled`

`transaction.enabled`

`cluster.node.scanner_management.expiration_time_millis`

Performance-related configurations

`parallel_executor_count`

`parallel_preparation.enabled`

`parallel_validation.enabled`

`parallel_commit.enabled`

`parallel_rollback.enabled`

`async_commit.enabled`

`async_rollback.enabled`

`parallel_implicit_pre_read.enabled`

`one_phase_commit.enabled`

`coordinator.write_omission_on_read_only.enabled`

`coordinator.group_commit.enabled`

`coordinator.group_commit.slot_capacity`

`coordinator.group_commit.group_size_fix_timeout_millis`

`coordinator.group_commit.delayed_slot_move_timeout_millis`

`coordinator.group_commit.old_group_abort_timeout_millis`

`coordinator.group_commit.timeout_check_interval_millis`

`coordinator.group_commit.metrics_monitor_log_enabled`

Storage-related configurations

`storage`

`contact_points`

`username`

`password`

`jdbc.connection_pool.min_idle`

`jdbc.connection_pool.max_idle`

`jdbc.connection_pool.max_total`

`jdbc.prepared_statements_pool.enabled`

`jdbc.prepared_statements_pool.max_open`

`jdbc.isolation_level`

`jdbc.table_metadata.connection_pool.min_idle`

`jdbc.table_metadata.connection_pool.max_idle`

`jdbc.table_metadata.connection_pool.max_total`

`jdbc.admin.connection_pool.min_idle`

`jdbc.admin.connection_pool.max_idle`

`jdbc.admin.connection_pool.max_total`

`jdbc.db2.variable_key_column_size`

`jdbc.db2.time_column.default_date_component`

`storage`

`contact_points`

`username`

`password`

`dynamo.endpoint_override`

`dynamo.namespace.prefix`

`storage`

`contact_points`

`password`

`cosmos.consistency_level`

`storage`

`contact_points`

`contact_port`

`username`

`password`

Multi-storage support

Cross-partition scan configurations

`cross_partition_scan.enabled`

`cross_partition_scan.filtering.enabled`

`cross_partition_scan.ordering.enabled`

Scan fetch size

`scan_fetch_size`

GraphQL-related configurations

`graphql.enabled`