> ## 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_hyperscan_* session settings

> ClickHouse session settings in the max_hyperscan_* 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.settings](/docs/reference/system-tables/settings) and are autogenerated from [source](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/Settings.cpp).

<h2 id="max_hyperscan_regexp_length">
  max\_hyperscan\_regexp\_length
</h2>

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

Defines the maximum length for each regular expression in the [hyperscan multi-match functions](/docs/reference/functions/regular-functions/string-search-functions#multiMatchAny).

Possible values:

* Positive integer.
* 0 - The length is not limited.

**Example**

Query:

```sql theme={null}
SELECT multiMatchAny('abcd', ['ab','bcd','c','d']) SETTINGS max_hyperscan_regexp_length = 3;
```

Result:

```text theme={null}
┌─multiMatchAny('abcd', ['ab', 'bcd', 'c', 'd'])─┐
│                                              1 │
└────────────────────────────────────────────────┘
```

Query:

```sql theme={null}
SELECT multiMatchAny('abcd', ['ab','bcd','c','d']) SETTINGS max_hyperscan_regexp_length = 2;
```

Result:

```text theme={null}
Exception: Regexp length too large.
```

**See Also**

* [max\_hyperscan\_regexp\_total\_length](/docs/reference/settings/session-settings/max-hyperscan#max_hyperscan_regexp_total_length)

<h2 id="max_hyperscan_regexp_total_length">
  max\_hyperscan\_regexp\_total\_length
</h2>

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

Sets the maximum length total of all regular expressions in each [hyperscan multi-match function](/docs/reference/functions/regular-functions/string-search-functions#multiMatchAny).

Possible values:

* Positive integer.
* 0 - The length is not limited.

**Example**

Query:

```sql theme={null}
SELECT multiMatchAny('abcd', ['a','b','c','d']) SETTINGS max_hyperscan_regexp_total_length = 5;
```

Result:

```text theme={null}
┌─multiMatchAny('abcd', ['a', 'b', 'c', 'd'])─┐
│                                           1 │
└─────────────────────────────────────────────┘
```

Query:

```sql theme={null}
SELECT multiMatchAny('abcd', ['ab','bc','c','d']) SETTINGS max_hyperscan_regexp_total_length = 5;
```

Result:

```text theme={null}
Exception: Total regexp lengths too large.
```

**See Also**

* [max\_hyperscan\_regexp\_length](/docs/reference/settings/session-settings/max-hyperscan#max_hyperscan_regexp_length)