> ## 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.

# s3_validate_* session settings

> ClickHouse session settings in the s3_validate_* 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="s3_validate_etag_on_read">
  s3\_validate\_etag\_on\_read
</h2>

<SettingsInfoBlock type="Bool" default_value="1" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.7"},{"label": "1"},{"label": "New setting to detect concurrent in-place overwrites of S3\/GCS objects during a read by validating the GET response ETag against the listed one. previous_value=false so `compatibility` with versions before 26.7 restores the pre-existing behavior (no validation)."}]}]} />

When reading an object from S3 (or an S3-compatible store such as GCS), check that every GET request returns the same ETag that was observed when the object was listed. A single file read issues many ranged GET requests; if the object is overwritten in place between them (for example by an external writer rewriting a fixed key), the reads can otherwise be stitched together from two different object generations and surface as a corrupted checksum or parse error. When a mismatch is detected the read fails with `S3_OBJECT_CHANGED_DURING_READ` instead of returning inconsistent data. Disable only for workloads that intentionally read objects that are being overwritten and can tolerate inconsistent reads.

<h2 id="s3_validate_request_settings">
  s3\_validate\_request\_settings
</h2>

<SettingsInfoBlock type="Bool" default_value="1" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "24.6"},{"label": "1"},{"label": "Allow to disable S3 request settings validation"}]}]} />

Enables s3 request settings validation.
Possible values:

* 1 — validate settings.
* 0 — do not validate settings.