databendlabs/databend · error

get_input_read_buffer_size should not fail

Error message

get_input_read_buffer_size should not fail

What it means

streaming_load_handler_inner reads the session setting `input_read_buffer_size` via get_input_read_buffer_size(), which returns Result because the setting value must parse as a number. The code expects it to always be valid since defaults are correct; an Err means the setting holds an unparseable/invalid value in the session, so the handler panics with 500.

Solutions

1. Check the session/global value: `SELECT value FROM system.settings WHERE name='input_read_buffer_size'` and reset it with `SET input_read_buffer_size=<valid integer>`.
2. Reset to default: `SET GLOBAL input_read_buffer_size = DEFAULT` (or restart session).
3. Upgrade/patch so get_input_read_buffer_size maps errors to a 400 instead of expect().
4. Validate any client-supplied settings at connection time.

Example fix

// before
let input_read_buffer_size = settings.get_input_read_buffer_size().expect("get_input_read_buffer_size should not fail") as usize;
// after
let input_read_buffer_size = settings.get_input_read_buffer_size()
    .map_err(|e| HttpErrorCode::bad_request(format!("invalid input_read_buffer_size: {e}")))? as usize;

SELECT value FROM system.settings WHERE name = 'input_read_buffer_size'; -- must be a plain integer

fn is_valid_buffer_size(v: &str) -> bool { v.parse::<u64>().is_ok() }

let size = settings.get_input_read_buffer_size()
    .map_err(|e| HttpErrorCode::bad_request(format!("invalid input_read_buffer_size: {e}")))?;

When it happens

Trigger: A session-level or global setting `input_read_buffer_size` was set to a non-numeric or invalid value (e.g. via SET or a connection settings string) before running the streaming load (POST /v1/streaming_load).

Common situations: Copy-pasted connection strings with wrong setting syntax; tenants overriding settings with formatted values like '128MB' where a plain integer is required; corrupted settings from older versions.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• Invalid config.rpc
• {}
• Temp table id used up
• Invalid temp table desc
• expect tuple type

AI-assisted analysis of databendlabs/databend@288d84d76e (2026-09-11). Data as JSON: /api/errors/940db88d90e3197d. Report an issue: GitHub.

Appendix: source

Thrown at src/query/service/src/servers/http/v1/streaming_load.rs:236

    let settings = query_context.get_settings();

    let mut planner = Planner::new(query_context.clone());
    let (mut plan, extras) = planner
        .plan_sql(sql)
        .await
        .map_err(|err| err.display_with_sql(sql))
        .map_err(BadRequest)?;

    let entry = QueryEntry::create(&query_context, &plan, &extras).map_err(InternalServerError)?;
    let _guard = QueriesQueueManager::instance()
        .acquire(entry)
        .await
        .map_err(InternalServerError)?;

    let input_read_buffer_size = settings
        .get_input_read_buffer_size()
        .expect("get_input_read_buffer_size should not fail")
        as usize;

    match &mut plan {
        Plan::Insert(insert) => match &mut insert.source {
            InsertInputSource::StreamingLoad(streaming_load) => {
                if !streaming_load.file_format.support_streaming_load() {
                    return Err(poem::Error::from_string(
                        format!(
                            "Unsupported file format: {}",
                            streaming_load.file_format.get_type()
                        ),
                        StatusCode::BAD_REQUEST,
                    ));
                }
                let (tx, rx) = tokio::sync::mpsc::channel(1);
                *streaming_load.receiver.lock() = Some(rx);

                let format = streaming_load.file_format.clone();

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