Does a ResultSet load all data into memory or only when requested?

Question

I have a .jsp page where I have a GUI table that displays records from an Oracle database. This table allows typical pagination behaviour, such as \"FIRST\", \"NEXT\", \"PRE

Answer 1

The JDBC spec does not specify whether the data is streamed or if it is loaded into memory. Oracle streams by default. MySQL does not. To get MySQL to stream the resultset, you need to set the following on the Statement:

    pstmt = conn.prepareStatement(
        sql,
        ResultSet.TYPE_FORWARD_ONLY,
        ResultSet.CONCUR_READ_ONLY);
    pstmt.setFetchSize(Integer.MIN_VALUE);