Urgent! Slow Result Set -- temp table slowing me??

Question

-- Running BC4J/JHeadstart/UIX
Description:
I have a uix page that calls a Servlet and passes a TABLE_NAME. The Servlet gets the TABLE_NAME and calls a class that extends oracle.jheadstart.persistence.bc4j.handler.DataSourceHandlerImpl to create a ViewObject and get the data we need. Once the ViewObject is passed back to the servlet, the servlet loops through the VIewObject and builds a report. See the problem below and the code at the bottom.
Problem:
I am running a query that returns approx 5000 records to my ViewObject. I then loop through the rows and construct a report. The view object will return the first 1085 records quickly, however, the following 4000 come back very slowly. I read online that BC4J creates temp tables to store large resultsets and then streams the data to the user as you need it. Is this our potential bottleneck?
Questions:
Is there a way to have it return all the rows? What can I do to speed this up?
Code:
--- Begin Servlet Snippet ---
private ByteArrayOutputStream createReport(HttpServletRequest request)
try{
// PARM_REPORT = table name
String reportName = request.getParameter(PARM_REPORT);
System.out.println(">> calling getReport for " + reportName);
RdmUserHandlerImpl handler = new RdmUserHandlerImpl();
ViewObject vo = handler.getReportView2(reportName, request.getSession().getId());
System.out.println(">> back from get report");
// loop through report and print every 100
while(vo.hasNext())
curRow++;
if (curRow % 100 == 0 )
System.out.println(curRow + "");
--- End Servlet Snippet ---
--- Begin RdmUserHandlerImpl Snippet ---
public ViewObject getReportView2(String tableName, Object sessionId) throws Exception {
System.out.println("IN GET REPORT VIEW");
ApplicationModule appMod = (ApplicationModule)getConnection("classpath...resource.MyUser", sessionId);
// First see if we already created the view definition
ViewObject vo = appMod.findViewObject(tableName);
// If it was already created then refresh it, else lets try to create it
if(vo != null) {
System.out.println("found existing view");
vo.reset();
else {
System.out.println("view not found, making new view");
String query="SELECT * FROM " + tableName;
System.out.println("QUERY = " + query);
vo = appMod.createViewObjectFromQueryStmt(tableName, query);
// max fetch returns -1
System.out.println("MAX Fetch Size = " + vo.getMaxFetchSize());
return vo;
--- End RdmUserHandlerImpl Snippet ---
Please reply asap! Deadline is coming fast!
-Matt

Answer 1

Matt,
I think that you are right, the temporary tables created by BC4J are the reason for making it slow after a certain number of records. One of Steve Muench's articles includes the text:
One of the most frequent performance-related questions we get on the Oracle Technet discussion forum is a question like, "After I query about a 1000 rows in a view object, my application gets very, very slow. What's happening?"
It explains how you can turn off this feature, see the full article at http://www.oracle.com/technology/products/jdev/tips/muench/voperftips/index.html.
The following article gives a lot of helpful information about the temporary tables:
http://www.oracle.com/technology/products/jdev/htdocs/bc4j/bc4j_temp_tables.html
The next article gives general tips for performance tuning of BC4J:
http://www.oracle.com/technology/products/jdev/howtos/10g/adfbc_perf_and_tuning.html
Hope this helps,
Sandra Muller
JHeadstart Team