> ## 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.

# min_* MergeTree table settings

> ClickHouse MergeTree table settings in the min_* 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="min_absolute_delay_to_close">
  min\_absolute\_delay\_to\_close
</h2>

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

Minimal absolute delay to close, stop serving requests and not
return Ok during status check.

<h2 id="min_columns_to_activate_adaptive_write_buffer">
  min\_columns\_to\_activate\_adaptive\_write\_buffer
</h2>

<SettingsInfoBlock type="UInt64" default_value="500" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.1"},{"label": "500"},{"label": "New setting"}]}]} />

Allow to reduce memory usage for tables with lots of columns by using adaptive writer buffers.

Possible values:

* 0 - unlimited
* 1 - always enabled

<h2 id="min_compress_block_size">
  min\_compress\_block\_size
</h2>

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

Minimum size of blocks of uncompressed data required for compression when
writing the next mark. You can also specify this setting in the global settings
(see [min\_compress\_block\_size](/docs/reference/settings/merge-tree-settings/min#min_compress_block_size)
setting). The value specified when the table is created overrides the global value
for this setting.

<h2 id="min_index_granularity_bytes">
  min\_index\_granularity\_bytes
</h2>

<SettingsInfoBlock type="UInt64" default_value="1024" />

Min allowed size of data granules in bytes.

To provide a safeguard against accidentally creating tables with very low
`index_granularity_bytes`.

<h2 id="min_marks_to_honor_max_concurrent_queries">
  min\_marks\_to\_honor\_max\_concurrent\_queries
</h2>

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

The minimal number of marks read by the query for applying the [max\_concurrent\_queries](/docs/reference/settings/merge-tree-settings/max#max_concurrent_queries)
setting.

<Note>
  Queries will still be limited by other `max_concurrent_queries` settings.
</Note>

Possible values:

* Positive integer.
* `0` — Disabled (`max_concurrent_queries` limit applied to no queries).

**Example**

```xml theme={null}
<min_marks_to_honor_max_concurrent_queries>10</min_marks_to_honor_max_concurrent_queries>
```

<h2 id="min_merge_bytes_to_use_direct_io">
  min\_merge\_bytes\_to\_use\_direct\_io
</h2>

<SettingsInfoBlock type="UInt64" default_value="10737418240" />

The minimum data volume for merge operation that is required for using direct
I/O access to the storage disk. When merging data parts, ClickHouse calculates
the total storage volume of all the data to be merged. If the volume exceeds
`min_merge_bytes_to_use_direct_io` bytes, ClickHouse reads and writes the
data to the storage disk using the direct I/O interface (`O_DIRECT` option).
If `min_merge_bytes_to_use_direct_io = 0`, then direct I/O is disabled.

<h2 id="min_parts_to_merge_at_once">
  min\_parts\_to\_merge\_at\_once
</h2>

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

Minimal amount of data parts which merge selector can pick to merge at once
(expert level setting, don't change if you don't understand what it is doing).
0 - disabled. Works for Simple and StochasticSimple merge selectors.

<h2 id="min_replicated_logs_to_keep">
  min\_replicated\_logs\_to\_keep
</h2>

<SettingsInfoBlock type="UInt64" default_value="10" />

Keep about this number of last records in ZooKeeper log, even if they are
obsolete. It doesn't affect work of tables: used only to diagnose ZooKeeper
log before cleaning.

Possible values:

* Any positive integer.