prestodb/presto · error · SQLException

Fetch size must be positive

Error message

Fetch size must be positive

What it means

setFetchSize in PrestoStatement rejects negative values with this SQLException: a fetch size must be zero (driver default) or a positive row count. It is a pure input validation guard before storing the value in fetchSize.

Source

Thrown at presto-jdbc/src/main/java/com/facebook/presto/jdbc/PrestoStatement.java:390

        }
        // ignore: fetch direction is always forward
    }

    @Override
    public int getFetchDirection()
            throws SQLException
    {
        checkOpen();
        return ResultSet.FETCH_FORWARD;
    }

    @Override
    public void setFetchSize(int rows)
            throws SQLException
    {
        checkOpen();
        if (rows < 0) {
            throw new SQLException("Fetch size must be positive");
        }
        fetchSize.set(rows);
    }

    @Override
    public int getFetchSize()
            throws SQLException
    {
        checkOpen();
        return fetchSize.get();
    }

    @Override
    public int getResultSetConcurrency()
            throws SQLException
    {
        checkOpen();
        return ResultSet.CONCUR_READ_ONLY;

View on GitHub (pinned to 55bb57d202)

Solutions

1. Pass 0 to use the driver default or a positive integer for the fetch size
2. Validate configured fetch-size settings before applying them to statements
3. Catch SQLException when fetch size originates from external configuration

When it happens

Trigger: Thrown at presto-jdbc/src/main/java/com/facebook/presto/jdbc/PrestoStatement.java:390 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/9973085ecf76e80f. Report an issue: GitHub.