> ## 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.

# max_number_* MergeTree table settings

> ClickHouse MergeTree table settings in the max_number_* 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="max_number_of_merges_with_ttl_in_pool">
  max\_number\_of\_merges\_with\_ttl\_in\_pool
</h2>

<SettingsInfoBlock type="UInt64" default_value="2" />

When there is
more than specified number of merges with TTL entries in pool, do not assign
new merge with TTL. This is to leave free threads for regular merges and
avoid "Too many parts"

<h2 id="max_number_of_mutations_for_replica">
  max\_number\_of\_mutations\_for\_replica
</h2>

<SettingsInfoBlock type="UInt64" default_value="0" />

Limit the number of part mutations per replica to the specified amount.
Zero means no limit on the number of mutations per replica (the execution can
still be constrained by other settings).