Using Cursors

Cursors enable applications to process very large data sets. Cursors should also be used where the number of query rows cannot be predicted and may be larger than your JavaScript engine can handle in a single array. A Cursor object is obtained by setting cursor: true in the options parameter of the Connection.execute() method when executing a query. Cursor fetches rows in batches. Cursor.next() method returns the next row from the internal cache. When internal cache is empty, it fetches next batch of rows from the server. fetchCount property lets you set the batch size. Where there is no more row to fetch, Cursor is closed automatically and next() method returns undefined;

const qr = await connection.query('select * from my_table',
        {cursor: true, fetchCount: 250});
console.log(qr.fields);
const cursor = qr.cursor;
let row;
while ((row = await cursor.next())) {
    console.log(row);
}
await cursor.close(); // When you done, close the cursor to release resources