[DERBY-6946] Argument checking for EmbedResultSet_setFetchSize(int) may be incorrect

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 10.12.1.1
• Component/s: JDBC
• Assignee: Unassigned
• Reporter: Hao Zhong
• Created: 05/Jul/17 08:44
• Updated: 06/Jul/17 00:38

Description

The EmbedResultSet_setFetchSize method has the following code to check its argument:

public void setFetchSize(int rows) throws SQLException {
		checkStatus();
        if (rows < 0  || (this.getMaxRows() != 0 && 
                             rows > this.getMaxRows()))
        {
	        throw newSQLException(SQLState.INVALID_ST_FETCH_SIZE, rows);
        }else if ( rows > 0 ) // ignore the call if the value is zero
            fetchSize = rows;
	}

The check seems to be incorrect. DERBY-3573 fixed a similar problem, and explained why the check is incorrect. The buggy code is as follow:

public void setFetchSize(int rows) throws SQLException {
		checkIfClosed("setFetchSize");
		if (rows < 0 || (stmt.getMaxRows() != 0 && rows > stmt.getMaxRows())) {
			throw Util.generateCsSQLException(SQLState.INVALID_FETCH_SIZE,
					new Integer(rows));
		} else if (rows > 0) // if it is zero ignore the call
		{
			fetchSize = rows;
		}
	}

The fixed code is:

public void setFetchSize(int rows) throws SQLException {
		checkIfClosed("setFetchSize");
		if (rows < 0) {
			throw Util.generateCsSQLException(SQLState.INVALID_FETCH_SIZE,
					new Integer(rows));
		} else if (rows > 0) // if it is zero ignore the call
		{
			fetchSize = rows;
		}
	}