As you already know (if you've read the Introduction) there are two variants of Smart Rendering in dhtmlxGrid. We'll concentrate on more complex one, which allows you working with much bigger datasets. I mean Smart Rendering with Dynamic Loading. Below there are samples of server side code for creating an output XML based on incoming arguments and MySQL database for 4 most popular technologies. Load your variant of file with the following command (put it into script block right after mygrid.enableSmartRendering):

gridQString = "getGridRecords.php";//save query string to global variable (see step 5 for details)
mygrid.loadXML(gridQString );

Sending the request to the URL you specify inside loadXML method, grid adds two properties: posStart - starting position of record in the dataset (if this property was skipped, then it returns records from the beginning of the dataset); count - number of records to be returned with XML. Thus GET request which comes to the server will look something like this: getGridRecords.php?posStart=199&count=100 .

    <?php
        //set content type and xml tag
        header("Content-type:text/xml");
        print("<?xml version=
  "1.0
  "?>");
 
        //define variables from incoming values
        if(isset($_GET["posStart"]))
            $posStart = $_GET['posStart'];
        else
            $posStart = 0;
        if(isset($_GET["count"]))
            $count = $_GET['count'];
        else
            $count = 100;
 
        //connect to database
        $link = mysql_pconnect("localhost", "user", "pwd");
        $db = mysql_select_db ("sampleDB");
 
        //create query to products table
        $sql = "SELECT  * FROM products";
 
        //if this is the first query - get total number of records in the query result
        if($posStart==0){
            $sqlCount = "Select count(*) as cnt from ($sql) as tbl";
            $resCount = mysql_query ($sqlCount);
            $rowCount=mysql_fetch_array($resCount);
            $totalCount = $rowCount["cnt"];
        }
 
        //add limits to query to get only rows necessary for the output
        $sql.= " LIMIT ".$posStart.",".$count;
 
        //query database to retrieve necessary block of data
        $res = mysql_query ($sql);
 
        //output data in XML format   
        print("<rows total_count='".$totalCount."' pos='".$posStart."'>");   
        while($row=mysql_fetch_array($res)){
            print("<row id='".$row['id']."'>");
                print("<cell>");
                    print($row['nm']);  //value for product name
                print("</cell>");
                print("<cell>");
                    print($row['code']);  //value for internal code
                print("</cell>");
                print("<cell>");
                    print($row['num_val']);    //value for price
                print("</cell>");
             print("</row>");
        }
        print("</rows>");
    ?>

sample code was simplified to concentrate you on the main commands. Some necessary error handlers etc. were omitted.

  <%@ page import = "java.sql.*" %>
  <%
      String db_ipp_addr = "localhost";
      String db_username = "root";
      String db_password = "1";
      String db_name = "sampleDB";
 
      // set content type and xml tag
      response.setContentType("text/xml");
      out.println("<?xml version=
  "1.0
  " encoding=
  "UTF-8
  "?>");
 
      // define variables from incoming values
      String posStart = "";
      if (request.getParameter("posStart") != null){
          posStart = request.getParameter("posStart");
      }else{
          posStart = "0";
      }   
 
      String count = "";
      if (request.getParameter("count") != null){
          count = request.getParameter("count");
      }else{
          count = "100";   
      }   
 
      // connect to database
      Connection connection = null;
      Statement statement = null;
      ResultSet rs = null;
      String connectionURL = "jdbc:mysql://" + db_ipp_addr + ":3306/" + db_name;
 
      Class.forName("com.mysql.jdbc.Driver").newInstance();
      connection = DriverManager.getConnection(connectionURL, db_username, db_password);
 
      // query to products table
      String sql = "SELECT  * FROM products";
 
      // if this is the first query - get total number of records in the query result
      String totalCount = "";
      if (posStart.equals("0")){
          String sqlCount = "Select count(*) as cnt from (" + sql + ") as tbl";
          statement = connection.createStatement();
          rs = statement.executeQuery(sqlCount);
          rs.next();
          totalCount = rs.getString("cnt");
          rs.close();
      } else {
          totalCount = "";
      }
 
      // add limits to query to get only rows necessary for output
      sql += " LIMIT " + posStart + "," + count;
 
      // Execute the query
      statement = connection.createStatement();
      rs = statement.executeQuery(sql);
 
      // output data in XML format  
      out.println("<rows total_count='" + totalCount + "' pos='" + posStart + "'>");
      while (rs.next()) {
          out.println("<row id='" + rs.getString("id") + "'>");
              out.println("<cell>");
                  out.println(rs.getString("nm"));  // value for product name
              out.println("</cell>");
              out.println("<cell>");
                  out.println(rs.getString("code")); // value for internal code
              out.println("</cell>");
              out.println("<cell>");
                  out.println(rs.getString("num_val"));   // value for price
              out.println("</cell>");
          out.println("</row>");
      }
      out.write("</rows>");
      rs.close();
  %>

  <%@ LANGUAGE = VBScript %>
  <% option explicit %>
 
  <%
      Dim db_ipp_addr, db_username, db_password, db_name
      db_ipp_addr = "localhost"
      db_username = "root"
      db_password = "1"
      db_name = "sampleDB"
 
      ' set content type and xml tag
      Response.ContentType = "text/xml"
      Response.write("<?xml version=""1.0"" encoding=""UTF-8""?>")
 
      ' define variables from incoming values
      Dim posStart, count
      If not isEmpty(Request.QueryString("posStart")) Then
          posStart = Request.QueryString("posStart")
      Else
          posStart = 0
      End If   
 
      If not isEmpty(Request.QueryString("count")) Then
          count = Request.QueryString("count")
      Else
          count = 100
      End If   
 
      ' connect to database
      Dim objConnection, rs, connString, sql
      Set objConnection = Server.CreateObject("ADODB.Connection")
      Set rs = Server.CreateObject("ADODB.Recordset")
      connString###### "DRIVERMySQL ODBC 3.51 Driver}; SERVER=" &amp; db_ipp_addr &amp; "; 
DATABASE=" &amp; db_name &amp; "; UID=" &amp; db_username &amp; "; PWD=" &amp; db_password
      objConnection.Open connString
 
 
      ' query to products table
      sql = "SELECT  * FROM products"
 
      ' if this is the first query - get total number of records in the query result
      Dim sqlCount, totalCount
      If posStart = 0 Then
          sqlCount = "Select count(*) as cnt from (" &amp; sql &amp; ") as tbl"
          rs.Open sqlCount, objConnection
          totalCount = rs("cnt")
          rs.Close
      Else
          totalCount = ""   
      End If
 
      ' add limits to query to get only rows necessary for output
      sql = sql &amp; " LIMIT " &amp; posStart &amp; "," &amp; count
 
      ' Execute the query
      rs.Open sql, objConnection
 
      ' output data in XML format  
      Response.write("<rows total_count='" &amp; totalCount &amp; "' pos='" &amp; posStart &amp; "'>")
      Do while not rs.EOF
          Response.write("<row id='" &amp; rs("id") &amp; "'>")
              Response.write("<cell>")
                  Response.write(rs("nm"))  ' value for product name
              Response.write("</cell>")
              Response.write("<cell>")
                  Response.write(rs("code"))  ' value for internal code
              Response.write("</cell>")
              Response.write("<cell>")
                  Response.write(rs("num_val"))    ' value for price
              Response.write("</cell>")
          Response.write("</row>")
          rs.MoveNext
      Loop
      Response.write("</rows>")
      rs.Close
      Set rs = Nothing
      objConnection.Close
      Set objConnection = Nothing
  %>

  <cfset dsn = "sampleDB">
  <cfsetting  enablecfoutputonly="yes">
 
  <!--- set content type and xml tag --->
  <cfcontent reset="yes" type="text/xml; charset=UTF-8"><cfoutput><?xml version="1.0"?></cfoutput>
 
      <!---    define variables from incoming values --->
      <cfif isDefined("url.posStart")>
          <cfset posStart = url.posStart>
      <cfelse>
          <cfset posStart = 0>
      </cfif>   
 
      <cfif isDefined("url.count")>
          <cfset count = url.count>
      <cfelse>
          <cfset count = 100>
      </cfif>   
 
      <!--- if this is the first query - get total number of records in the query result --->
      <cfif posStart eq 0>
          <cfquery datasource="#dsn#" name="getCount">
              Select count(*) as cnt
              FROM products
          </cfquery>
          <cfset totalCount = getCount.cnt>
      <cfelse>
          <Cfset totalCount = "">   
      </cfif>
 
      <!--- query to products table --->
      <cfquery datasource="#dsn#" name="getRecords">
          SELECT  *
          FROM products
          <!--- add limits to query to get only rows necessary for output --->
          LIMIT #posStart#, #count#
      </cfquery>
 
      <!--- output data in XML format   --->
      <cfoutput><rows total_count="#totalCount#" pos="#posStart#"></cfoutput>  
      <cfloop query="getRecords">
          <cfoutput><row id="#getRecords.id#"></cfoutput>
              <!--- value for product name --->
              <cfoutput><cell>#getRecords.nm#</cell></cfoutput>
              <!--- value for internal code --->
              <cfoutput><cell>#getRecords.code#</cell></cfoutput>
              <!--- value for price --->
              <cfoutput><cell>#getRecords.num_val#</cell></cfoutput>
          <cfoutput></row></cfoutput>
      </cfloop>
      <cfoutput></rows></cfoutput>

After loading the file the grid will look something like in the picture below. When you stop scrolling the grid will load and draw a new portion of records.