# setMaxBlockSizeForReservedMemory {#setmaxblocksizeforreservedmemory}

**Parent topic:**[Functions](../../Functions/category.md)

## Syntax {#syntax}

`setMaxBlockSizeForReservedMemory(blockSizeKB)`

## Arguments {#arguments}

**blockSizeKB** is a positive integer or floating-point number \(in KB\).

## Details {#details}

Modify the maximum reserved memory allocated to a DolphinDB block online. This command can only be executed by the admin on the data node.

**Note:** The modified configuration is only valid for the current node, and will expire after the system restarts. To make it permanent, please change the configuration parameter *maxBlockSizeForReservedMemory*.

