jackc/pgx · error

statement description failed: %w

Error message

statement description failed: %w

What it means

Error "statement description failed: %w" thrown in jackc/pgx.

Source

Thrown at copy_from.go:155

	switch ct.mode {
	case QueryExecModeExec, QueryExecModeSimpleProtocol:
		// These modes don't support the binary format. Before the inclusion of the
		// QueryExecModes, Conn.Prepare was called on every COPY operation to get
		// the OIDs. These prepared statements were not cached.
		//
		// Since that's the same behavior provided by QueryExecModeDescribeExec,
		// we'll default to that mode.
		ct.mode = QueryExecModeDescribeExec
		fallthrough
	case QueryExecModeCacheStatement, QueryExecModeCacheDescribe, QueryExecModeDescribeExec:
		var err error
		sd, err = ct.conn.getStatementDescription(
			ctx,
			ct.mode,
			fmt.Sprintf("select %s from %s", quotedColumnNames, quotedTableName),
		)
		if err != nil {
			return 0, fmt.Errorf("statement description failed: %w", err)
		}
	default:
		return 0, fmt.Errorf("unknown QueryExecMode: %v", ct.mode)
	}

	r, w := io.Pipe()
	doneChan := make(chan struct{})

	go func() {
		defer close(doneChan)

		// Purposely NOT using defer w.Close(). See https://github.com/golang/go/issues/24283.
		buf := ct.conn.wbuf

		buf = append(buf, "PGCOPY\n\377\r\n\000"...)
		buf = pgio.AppendInt32(buf, 0)
		buf = pgio.AppendInt32(buf, 0)

View on GitHub (pinned to ec1a0befd2)

When it happens

Trigger: Thrown at copy_from.go:155 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of jackc/pgx@ec1a0befd2 (2026-08-04). Data as JSON: /data/errors/5c57124c15289195.json. Report an issue: GitHub.