Help Center/ MapReduce Service/ Component Operation Guide (LTS)/ Using ClickHouse/ Enterprise-Class Enhancements of ClickHouse/ ClickHouse Multi-Tenancy/ Modifying the Memory Limit of ClickHouse on a ClickHouseServer Node
Updated on 2025-08-22 GMT+08:00
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Modifying the Memory Limit of ClickHouse on a ClickHouseServer Node

Scenarios

Modify the maximum memory allowed for ClickHouse on a ClickHouseServer node to ensure the normal use of other service instances on the node.

Notes and Constraints

This section applies only to MRS 3.2.0-LTS or later.

Procedure

  1. Log in to FusionInsight Manager.

    For details, see Accessing FusionInsight Manager.

  2. Choose Cluster > Services > ClickHouse. Click Configuration then All Configurations, and choose ClickHouseServer(Role) > Performance.

  3. Change the value of max_server_memory_usage_to_ram_ratio as required and save the configuration.

    • Restart is not required for the modification to take effect.
    • The value can be -1 or a number between 0 and 1, indicating the proportion of the server's total RAM that ClickHouse can use. For example, if the server has 10 GB of physical memory (RAM) and the limit is set to 0.9, the memory available to ClickHouse on the current server is 9 GB (10 GB x 0.9). Setting the value to 0 removes the memory usage limit, allowing ClickHouse to use all physical memory of the server. Setting the value to -1 allows the system to dynamically adjust memory allocation. The value of this parameter can contain a maximum of two decimal places.

Parent topic: ClickHouse Multi-Tenancy