prestodb/presto · error · SQLFeatureNotSupportedException

isFirst

Error message

isFirst

What it means

isFirst cannot be answered by the Presto driver because its result sets are forward-only streams with no absolute row positioning; PrestoResultSet throws SQLFeatureNotSupportedException unconditionally. The capability simply does not exist in this driver.

Source

Thrown at presto-jdbc/src/main/java/com/facebook/presto/jdbc/PrestoResultSet.java:629

    @Override
    public boolean isBeforeFirst()
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("isBeforeFirst");
    }

    @Override
    public boolean isAfterLast()
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("isAfterLast");
    }

    @Override
    public boolean isFirst()
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("isFirst");
    }

    @Override
    public boolean isLast()
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("isLast");
    }

    @Override
    public void beforeFirst()
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("beforeFirst");
    }

    @Override
    public void afterLast()

View on GitHub (pinned to 55bb57d202)

Solutions

  1. Use a boolean/counter flag set when the first rs.next() succeeds
  2. If first/last distinctions matter, materialize the rows into a List first
  3. Never rely on cursor-position APIs against Presto result sets

Example fix

// before
while (rs.next()) { if (rs.isFirst()) renderHeader(); renderRow(rs); }
// after
boolean first = true;
while (rs.next()) { if (first) { renderHeader(); first = false; } renderRow(rs); }
Defensive patterns

Strategy: try-catch

Validate before calling

if (rs instanceof com.facebook.presto.jdbc.PrestoResultSet) {
    // maintain a first-row flag yourself
}

Type guard

boolean isPrestoResultSet(ResultSet rs) { return rs instanceof com.facebook.presto.jdbc.PrestoResultSet; }

Try / catch

try {
    boolean first = rs.isFirst();
} catch (SQLFeatureNotSupportedException e) {
    // maintain your own row counter/flag
}

Prevention

When it happens

Trigger: Calling rs.isFirst() on a PrestoResultSet, often in row-number-sensitive processing logic.

Common situations: Rendering code that special-cases the first row; frameworks migrated from scrollable result-set drivers.

Related errors

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/cf6e914fce1f7671. Report an issue: GitHub.