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View and configure system parameters

What are system parameters?

System parameters in RisingWave refer to the parameters that advanced users can use to adjust how internal components work in RisingWave.

Currently, these system parameters are availble in RisingWave.

barrier_interval_msThe time interval of the periodic barriers.
checkpoint_frequencySpecify the number of barriers for which a checkpoint will be created. The value must be a positive integer.
sstable_size_mbThe target size of SSTable.
block_size_kbThe size of each block in bytes in SSTable.
bloom_false_positiveFalse positive rate of bloom filter in SSTable.
state_storeThe state store URL.
data_directoryThe remote directory for storing data and metadata objects.
backup_storage_urlThe URL of the remote storage for backups.
backup_storage_directoryThe directory of the remote storage for backups.
telemetry_enabledWhether to enable telemetry or not. For more information, see Telemetry.
max_concurrent_creating_streaming_jobsThe maximum number of streaming jobs that can be created concurrently. That is, the maximum of materialized views, indexes, tables, sinks, or sources that can be created concurrently.

How to view system parameters?

You can use the SHOW PARAMETERS command to view the system parameters, along with their current values.

The Mutable column indicates whether the parameter can be altered using the ALTER SYSTEM SET command after the system is running. t means it can be altered using the ALTER SYSTEM SET command while f means it cannot be altered using the command.

           Name                         |     Value      | Mutable 
barrier_interval_ms | 1000 | f
checkpoint_frequency | 10 | t
sstable_size_mb | 256 | f
block_size_kb | 64 | f
bloom_false_positive | 0.001 | f
state_store | hummock+memory | f
data_directory | hummock_001 | f
backup_storage_url | memory | f
backup_storage_directory | backup | f
telemetry_enabled | true | t
max_concurrent_creating_streaming_jobs | 1 | t

How to configure system parameters?

Mutable and immutable parameters are configured differently.

You can configure mutable parameters using the ALTER SYSTEM SET command in psql.

The full syntax of the ALTER SYSTEM SET statement is:

ALTER SYSTEM SET parameter_name { TO | = } { value | 'value' | DEFAULT };

Immutable parameters need to be initialized in the CLI of the meta node. state_store and data_directory need to be initialized before starting a cluster.

To configure parameter settings in the CLI of the meta node, navigate to the directory where RisingWave is installed and run the following command:

meta-node --<parameter_name> <value>

For example, to initialize the setting of data_directory:

meta-node --data_directory "hummock_001"


As RisingWave reads system parameters at different times, there is no guarantee that a parameter value change takes effect immediately. We recommend that you adjust system parameters before running a streaming query after your RisingWave cluster starts.

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