influxdata/influxdb · error · Error::FieldRead

error reading field from body

Error message

error reading field from body: {name} -- {error}

What it means

Thrown when the server fails to read a field out of the request body while decoding the v1 query payload. `FieldRead { name, error }` names the offending field and carries the underlying read/deserialization error as a string. It indicates a malformed or unreadable request body rather than a query problem.

Solutions

1. Check the `name` and `error` fields in the message to identify the failing body field.
2. Send the body with the Content-Type the endpoint expects (application/x-www-form-urlencoded or application/json).
3. Validate the request payload against the API's expected schema before sending.
4. Log the raw request body at the client to confirm what was actually transmitted.

Example fix

// before
curl -d '{"q": "SELECT 1"}' /query  # wrong encoding for form endpoint
// after
curl --data-urlencode 'q=SELECT 1' -H 'Content-Type: application/x-www-form-urlencoded' /query

function buildQueryBody(fields) {
  return Object.fromEntries(
    Object.entries(fields).filter(([, v]) => v !== undefined).map(([k, v]) => [k, String(v)])
  );
}
// send with explicit Content-Type matching the endpoint
const body = new URLSearchParams(buildQueryBody({ q, db, rp }));

try {
  await postQuery(body);
} catch (e) {
  const m = /error reading field from body: (\w+)/.exec(e.message);
  if (m) console.error(`invalid request field: ${m[1]}`);
  else throw e;
}

When it happens

Trigger: POST to the v1 /query endpoint with a body whose fields cannot be read, e.g. malformed JSON/form encoding, wrong Content-Type, or a field value that cannot be deserialized into the expected type.

Common situations: Sending JSON to an endpoint expecting urlencoded form data (or vice versa); truncated request bodies from proxies; clients serializing fields with unexpected types (number where string expected).

Understand the failure class

Background: JSON parse error: "Unexpected token" / "not valid JSON" / "failed to parse" — what JSON parsers are really complaining about — this error's family across 45 libraries.

Related errors

• failed to deserialize db/rp/precision in request
• failed to deserialize org/bucket/precision in request
• invalid mime type ( )
• missing bucket value
• All `DataPoints` must have at least one field. Builder…

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/ae4e5492ce21af4e. Report an issue: GitHub.

Appendix: source

Thrown at core/iox_v1_query_api/src/error.rs:77

    InfluxqlNoDatabase,

    #[error(
        "provided a database in both the parameters ({param_db}) and \
        query string ({query_db}) that do not match, if providing a query \
        that specifies the database, you can omit the 'database' parameter \
        from your request"
    )]
    InfluxqlDatabaseMismatch { param_db: String, query_db: String },

    #[error(
        "provided a retention policy in both the parameters ({param_rp}) and \
        query string ({query_rp}) that do not match, if providing a query \
        that specifies the retention_policy, you can omit the 'rp' parameter \
        from your request"
    )]
    InfluxqlRetentionPolicyMismatch { param_rp: String, query_rp: String },

    #[error("error reading field from body: {name} -- {error}")]
    FieldRead { name: &'static str, error: String },

    #[error("Cannot retrieve database: {0}")]
    Database(DataFusionError),

    #[error("Database {0} not found")]
    DatabaseNotFound(String),

    #[error("v1 query API error: {0}")]
    V1Query(#[from] QueryError),
}

#[derive(Debug, Clone)]
pub enum HttpError {
    NotFound(String),
    Unauthorized(String),
    Invalid(String),
    InternalError(String),

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