> ## 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_selecting_* MergeTree table settings

> ClickHouse MergeTree table settings in the merge_selecting_* 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_selecting_sleep_ms">
  merge\_selecting\_sleep\_ms
</h2>

<SettingsInfoBlock type="UInt64" default_value="5000" />

Minimum time to wait before trying to select parts to merge again after no
parts were selected. A lower setting will trigger selecting tasks in
background\_schedule\_pool frequently which result in large amount of requests
to zookeeper in large-scale clusters

<h2 id="merge_selecting_sleep_slowdown_factor">
  merge\_selecting\_sleep\_slowdown\_factor
</h2>

<SettingsInfoBlock type="Float" default_value="1.2" />

The sleep time for merge selecting task is multiplied by this factor when
there's nothing to merge and divided when a merge was assigned