> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-revert-104359-revert-104251-parquet-single.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# text_index_* session settings

> ClickHouse session settings in the text_index_* generated group.

export const VersionHistory = ({rows = []}) => {
  if (rows.length === 0) {
    return null;
  }
  const headers = ["Version", "Default value", "Comment"];
  const border = "1px solid rgba(128, 128, 128, 0.3)";
  const cell = {
    border,
    padding: "0.25rem 0.5rem",
    textAlign: "start",
    verticalAlign: "top"
  };
  return <details className="not-prose" style={{
    border,
    borderRadius: "0.5rem",
    margin: "0.5rem 0",
    padding: "0.5rem 0.75rem",
    fontSize: "0.8125rem",
    lineHeight: "1.125rem"
  }}>
      <summary style={{
    cursor: "pointer",
    fontWeight: 600,
    opacity: 0.72
  }}>
        Version history
      </summary>
      <table style={{
    borderCollapse: "collapse",
    width: "100%",
    margin: "0.5rem 0 0"
  }}>
        <thead>
          <tr>
            {headers.map(header => <th key={header} style={{
    ...cell,
    fontWeight: 600,
    opacity: 0.72
  }}>
                {header}
              </th>)}
          </tr>
        </thead>
        <tbody>
          {rows.map((row, row_index) => <tr key={row.id ?? row_index}>
              {(row.items ?? []).map((item, item_index) => <td key={item_index} style={{
    ...cell,
    overflowWrap: "anywhere"
  }}>
                  {item?.label}
                </td>)}
            </tr>)}
        </tbody>
      </table>
    </details>;
};

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.settings](/reference/system-tables/settings) and are autogenerated from [source](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/Settings.cpp).

<h2 id="text_index_hint_max_selectivity">
  text\_index\_hint\_max\_selectivity
</h2>

<SettingsInfoBlock type="Float" default_value="0.2" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "25.12"},{"label": "0.2"},{"label": "New setting"}]}]} />

Maximal selectivity of the filter to use the hint built from the inverted text index.

<h2 id="text_index_lazy_intersection_density_threshold">
  text\_index\_lazy\_intersection\_density\_threshold
</h2>

**Aliases**: `text_index_density_threshold`

<SettingsInfoBlock type="Float" default_value="0.2" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.7"},{"label": "0.2"},{"label": "Renamed from `text_index_density_threshold` (kept as an alias); selects the posting list intersection algorithm in lazy posting list apply mode."}]}]} />

Posting list density threshold that selects the intersection algorithm in lazy posting list apply mode (`text_index_posting_list_apply_mode = 'lazy'`).
Below the threshold: leapfrog intersection (favors sparse posting lists). At or above: brute-force bitmap intersection (favors dense posting lists).

<h2 id="text_index_like_max_postings_to_read">
  text\_index\_like\_max\_postings\_to\_read
</h2>

<SettingsInfoBlock type="UInt64" default_value="50" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.4"},{"label": "50"},{"label": "New setting"}]}]} />

Maximum number of large postings to read when text index LIKE evaluation by the dictionary scan is enabled.

Requires `use_text_index_like_evaluation_by_dictionary_scan` to be enabled.

<h2 id="text_index_like_min_pattern_length">
  text\_index\_like\_min\_pattern\_length
</h2>

<SettingsInfoBlock type="UInt64" default_value="4" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.4"},{"label": "4"},{"label": "New setting"}]}]} />

Minimum length of the alphanumeric needle in a LIKE/ILIKE pattern, or of a `startsWith`/`endsWith` needle,
required to use the text index LIKE evaluation by the dictionary scan.
Patterns shorter than this threshold match too many dictionary tokens and are skipped to avoid expensive scans.

Requires `use_text_index_like_evaluation_by_dictionary_scan` to be enabled.

<h2 id="text_index_posting_list_apply_mode">
  text\_index\_posting\_list\_apply\_mode
</h2>

<SettingsInfoBlock type="TextIndexPostingListApplyMode" default_value="lazy" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.8"},{"label": "lazy"},{"label": "Text index queries now decode posting lists on demand with a cursor instead of materializing them into Roaring Bitmaps, which reduces memory usage and CPU time for selective queries."}]}, {"id": "row-2","items": [{"label": "26.6"},{"label": "materialize"},{"label": "New setting for lazy posting list apply mode"}]}]} />

Controls how posting lists are applied during text index queries.
'materialize' eagerly decodes posting lists into Roaring Bitmaps.
'lazy' (default) uses cursor-based on-demand decoding (requires an index format with a serialized codec).
'lazy' is applied only where it is supported: queries with patterns (such as `LIKE`) and parts with an index written by an older version fall back to 'materialize'.