> ## Documentation Index
> Fetch the complete documentation index at: https://clickhouse.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# merge_* MergeTree table settings

> ClickHouse MergeTree table settings in the merge_* generated group.

export const SettingsInfoBlock = ({type, default_value, changeable_without_restart}) => {
  return <div className="not-prose" style={{
    display: "flex",
    flexWrap: "wrap",
    alignItems: "baseline",
    columnGap: "0.5rem",
    rowGap: "0.125rem",
    margin: "0.375rem 0",
    fontSize: "0.8125rem",
    lineHeight: "1.125rem"
  }}>
      <div style={{
    fontWeight: 600,
    opacity: 0.72
  }}>Type</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{type}</div>
      <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>Default</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{default_value}</div>
      {changeable_without_restart && <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>
          Changeable without restart
        </div>}
      {changeable_without_restart && <div style={{
    overflowWrap: "anywhere"
  }}>
          {changeable_without_restart}
        </div>}
    </div>;
};

These settings are available in [system.merge\_tree\_settings](/docs/reference/system-tables/merge_tree_settings) and are autogenerated from ClickHouse source.

<h2 id="merge_total_max_bytes_to_prewarm_cache">
  merge\_total\_max\_bytes\_to\_prewarm\_cache
</h2>

<SettingsInfoBlock type="UInt64" default_value="16106127360" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "25.1"},{"label": "16106127360"},{"label": "Cloud sync"}]}]} />

Only available in ClickHouse Cloud. Maximal size of parts in total to prewarm
cache during merge.

<h2 id="merge_workload">
  merge\_workload
</h2>

Used to regulate how resources are utilized and shared between merges and
other workloads. Specified value is used as `workload` setting value for
background merges of this table. If not specified (empty string), then
server setting `merge_workload` is used instead.

**See Also**

* [Workload Scheduling](/docs/concepts/features/configuration/server-config/workload-scheduling)