📦 apache / fluss

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60---
title: Updating Configs
sidebar_position: 1
---
# Updating Configs

## Overview

Fluss allows you to update cluster or table configurations dynamically without requiring a cluster restart or table recreation. This section demonstrates how to modify and apply such configurations.

## Updating Cluster Configs

From Fluss version 0.8 onwards, some of the server configs can be updated without restarting the server.

Currently, the supported dynamically updatable server configurations include:
- `datalake.format`: Enable lakehouse storage by specifying the lakehouse format, e.g., `paimon`, `iceberg`.
- Options with prefix `datalake.${datalake.format}`
- `kv.rocksdb.shared-rate-limiter.bytes-per-sec`: Control RocksDB flush and compaction write rate shared across all RocksDB instances on the TabletServer. The rate limiter is always enabled. Set to a lower value (e.g., 100MB) to limit the rate, or a very high value to effectively disable rate limiting.


You can update the configuration of a cluster with [Java client](#using-java-client) or [Flink Procedures](engine-flink/procedures.md#cluster-configuration-procedures).

### Using Java Client

Here is a code snippet to demonstrate how to update the cluster configurations using the Java Client:

```java
// Enable lakehouse storage with Paimon format
admin.alterClusterConfigs(
        Collections.singletonList(
                new AlterConfig(DATALAKE_FORMAT.key(), "paimon", AlterConfigOpType.SET)));

// Disable lakehouse storage
admin.alterClusterConfigs(
        Collections.singletonList(
                new AlterConfig(DATALAKE_FORMAT.key(), "paimon", AlterConfigOpType.DELETE)));

// Set RocksDB shared rate limiter to 200MB/sec
admin.alterClusterConfigs(
        Collections.singletonList(
                new AlterConfig(KV_SHARED_RATE_LIMITER_BYTES_PER_SEC.key(), "200MB", AlterConfigOpType.SET)));
```

The `AlterConfig` class contains three properties:
* `key`: The configuration key to be modified (e.g., `datalake.format`)
* `value`: The configuration value to be set (e.g., `paimon`)
* `opType`: The operation type, either `AlterConfigOpType.SET` or `AlterConfigOpType.DELETE`

### Using Flink Stored Procedures

For certain configurations, Fluss provides convenient Flink stored procedures that can be called directly from Flink SQL. See [Procedures](engine-flink/procedures.md#cluster-configuration-procedures) for detailed documentation on using `get_cluster_config` and `set_cluster_config` procedures.

## Updating Table Configs

The connector options on a table including [Storage Options](engine-flink/options.md#storage-options) can be updated dynamically by [ALTER TABLE ... SET](engine-flink/ddl.md#alter-table) statement. See the example below:

```sql
-- Enable lakehouse storage for the given table
ALTER TABLE my_table SET ('table.datalake.enabled' = 'true');
```