edit.pdfjpgconverter.com |
||
.NET/Java PDF, Tiff, Barcode SDK LibraryTo get an idea of the impact on performance of changing fetch size, I wrote a benchmark program, BenchmarkPrefetch, that finds the elapsed time of a query retrieving 50,000 rows from t1. This program extends the utility class JBenchmark discussed in the section Timing Java Programs in 1. The program begins with import statements, getting a connection and invoking the method _runBenchmark(): /* This program benchmarks the impact of prefetch on a query. * COMPATIBLITY NOTE: runs successfully against 10.1.0.2.0, and 9.2.0.1.0 */ import java.sql.ResultSet; import java.sql.SQLException; import java.sql.CallableStatement; import java.sql.Connection; import oracle.jdbc.OracleTypes; import book.util.JDBCUtil; import book.util.JBenchmark; class BenchmarkPrefetch extends JBenchmark { public static void main(String args[]) { Connection conn = null; try { conn = JDBCUtil.getConnection("benchmark", "benchmark", "ora10g"); new BenchmarkPrefetch()._runBenchmark( conn ); qr code generator vb.net, onbarcode.barcode.winforms.dll crack, winforms code 128, vb.net generate ean 128, vb.net generate ean 13, codigo fuente pdf417 vb.net, itextsharp remove text from pdf c#, replace text in pdf c#, vb.net generate data matrix barcode, c# remove text from pdf,member this.Page_Load(sender: obj, e: EventArgs) = if not this.Page.IsPostBack then this.Time.Text <- DateTime.Now.ToString() member this.Reload_Click(sender: obj, e: EventArgs) = this.Time.Text <- "(R) " + DateTime.Now.ToString() } catch (Exception e) { // handle the exception properly - in this case, we just // print the stack trace. JDBCUtil.printException ( e ); } finally { // release the JDBC resources in the finally clause. JDBCUtil.close( conn ); } } // end of main() The following method, _runBenchmark(), prepares the statement to run our query that retrieves 50,000 rows. Before running the query, we start the SQL trace by invoking the method JDBCUtil.startTrace(). The query runs through a number of executions, each time retrieving a total of 50,000 rows using a given fetch size. The static array s_fetchSizes (declared later) defines all fetch sizes this program will benchmark our query on. Inside the loop, we find out the time taken by passing the fetch size information in an object array to the method timeMethod() inherited from JBenchmark: private void _runBenchmark( Connection conn ) throws Exception { String stmtString = "{ call prefetch_pkg.get_details ( , , ) }"; try { s_cstmt = conn.prepareCall( stmtString ); JDBCUtil.startTrace( conn ); for( int i=0; i < s_fetchSizes.length; i++ ) { Integer fetchSize = new Integer ( s_fetchSizes[i] ); timeMethod( JBenchmark.FIRST_METHOD, conn, new Object[]{fetchSize}, "Fetch Size: " + fetchSize ); } } finally { JDBCUtil.close( s_cstmt ); } } We override the method firstMethod() to execute our query for a given fetch size. Note that we once again put the fetch size inside a dummy hint that acts as our SQL tag: public void firstMethod( Connection conn, Object[] parameters ) throws Exception { ResultSet rset = null; Integer fetchSize = (Integer) parameters[0]; PreReleaseRequestState ReleaseRequestState PostReleaseRequestState PreUpdateRequestCache UpdateRequestCache PostUpdateRequestCache EndRequest PreSendRequestHeaders PreSendRequestContent The minimalist application shown in Listing 14-2 and Figure 14-1 does nothing but use the server to compute the time, something easily done on the local machine. Listing 14-6 shows the .aspx code for a web application shown in Figure 14-2 that computes a list of prime numbers for a selected range. The web.config file for this application remains the same. Listing 14-6. Computing and Displaying a Range of Prime Numbers Using the Web Server <%@ Page Language="F#" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script language="F#" runat="server"> member page.GenerateData_Click(sender: obj, e: EventArgs) = let isPrime(i: bigint) = let lim = Math.BigInt.FromInt64(int64(sqrt(float(i)))) let rec check j = j > lim or (i % j <> 0I && check (j+1I)) check 2I let lowerLimit = Math.BigInt.Parse(page.LowerLimit.Text) let upperLimit = Math.BigInt.Parse(page.UpperLimit.Text) let data = [ let previousTime = ref System.DateTime.Now for i in lowerLimit..upperLimit do if isPrime(i) then let time = System.DateTime.Now yield (i, time-previousTime.Value) do previousTime := time ] page.Repeater.DataSource <- data page.Repeater.DataBind() </script> <html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title>Current time</title> <style type="text/css"> body { font-family:calibri,verdana,sans-serif; } </style> try { String sqlTag = "/*+ FETCH_SIZE=" + fetchSize + "*/"; s_cstmt.setInt( 1, 50000); s_cstmt.setString( 2, sqlTag ); s_cstmt.registerOutParameter( 3, OracleTypes.CURSOR ); s_cstmt.execute(); rset = (ResultSet) s_cstmt.getObject( 3 ); rset.setFetchSize( fetchSize.intValue() ); int i=0; while (rset.next()) { i++; } } finally { // release JDBC-related resources in the finally clause. JDBCUtil.close( rset ); } } Finally, we declare the array containing fetch sizes for which this program was executed along with the static variable containing the CallableStatement object: private static int[] s_fetchSizes = {10, 20, 50, 100, 500, 1000, 5000, 10000, 30000}; private static CallableStatement s_cstmt; } // end of program The results of my run are shown in the chart in Figure 7-1.
|
||