Chapter 10 Achieving Optimum Performance with PowerDynamo

Writing cacheable documents

One of the most expensive tasks of a Web site is generating the output of a dynamic document. Caching a document's output with the cachedOutputTimeOut property can significantly reduce the time required by a Web site to respond to a request.

Write Web documents so as many as possible use cacheable output and have a cachedOutputTimeOut value assigned.

The following Web documents do not produce cacheable output:

Documents that require information from the user
Documents without a cachedOutputTimeOut value

Output that use variables given by the user are a good example of non-cacheable output. The first script in the example below, multiIntro.stm, displays a list of radio buttons for users to select the price range of products they would like to see.

Notes

The documents choice1.stm, choice2.stm, and choice3.stm all have cacheable output since each performs a specific query and requires no parameters.
If choice1.stm, choice2.stm, choice3.stm, and the output generated by each remain in the cache, a request for mulchoice.stm does not require any queries against the product table.

multiIntro.stm

<HTML>
<TITLE>multiIntro.stm</TITLE>
<BODY>
<H1>Product List</H1>
<P>The following items are available from the sample database</P>
<!--SQL
SELECT  name 
FROM  product
 -->
<TABLE BORDER>
<TR>
<TH>name</TH>
</TR>
<!--formatting--><TR>
<TD><!--data--></TD>
</TR><!--/formatting-->
</TABLE>
<P>Enter the price range you would like displayed</P>
<FORM METHOD=POST ACTION="mulchoice.stm" MULTIPLE SIZE="5">
<OL>
<INPUT TYPE="radio" NAME="choice" value="less10">Less than $10<BR>
<INPUT TYPE="radio" NAME="choice" value="less20">Less than $20, more than $10<BR>
<INPUT TYPE="radio" NAME="choice" value="less30">Less than $30, more than $20<BR>
</OL>
<P><INPUT TYPE="submit" VALUE="Submit List"></P>
<P><INPUT TYPE="RESET" VALUE="Clear Form"></P>
</FORM>
</BODY>
</HTML>

multiIntro.stm calls the following script, which in turn calls one of three scripts depending on the parameter being passed:

mulchoice.stm

<HTML>
<TITLE>Selected Products</TITLE>
<BODY>
<!--SCRIPT 
    
if( document.value.choice == "less10" ){
    x=site.Include('choice1.stm');
    document.WriteLn(x);
}
if( document.value.choice == "less20" ){
    x=site.Include('choice2.stm');
    document.WriteLn(x);
}
if( document.value.choice == "less30" ){
    x=site.Include('choice3.stm');
    document.WriteLn(x);
}
-->
</BODY>
</HTML>

choice1.stm

<H1>The following items are under $10.00 in price</H1>
<!--SQL
SELECT  product.name, product.color, product.unit_price
FROM DBA.product product
WHERE product.unit_price  <= 10.00
 -->
<TABLE BORDER>
<TR>
<TH>name</TH>
<TH>color</TH>
<TH>unit_price</TH>
</TR>
<!--formatting--><TR>
<TD><!--data--></TD>
<TD><!--data--></TD>
<TD><!--data--></TD>
</TR><!--/formatting-->
</TABLE>
<!--DOCUMENT CACHED_OUTPUT_TIMEOUT = 10 -->

choice2.stm

<H1>The following items are $10.00 to $20.00 in price</H1>
<!--SQL
SELECT  product.name, product.color, product.unit_price
FROM DBA.product product
WHERE product.unit_price <= 20.00 and product.unit_price >= 10.00

 -->
<TABLE BORDER>
<TR>
<TH>name</TH>
<TH>color</TH>
<TH>unit_price</TH>
</TR>
<!--formatting--><TR>
<TD><!--data--></TD>
<TD><!--data--></TD>
<TD><!--data--></TD>
</TR><!--/formatting-->
</TABLE>
<!--DOCUMENT CACHED_OUTPUT_TIMEOUT = 10 -->

choice3.stm

<H1>The following items are $20.00 to $30.00 in price</H1>
<!--SQL
SELECT  product.name, product.color, product.unit_price
FROM DBA.product product
WHERE product.unit_price  <= 30.00 and product.unit_price >= 20.00

 -->
<TABLE BORDER>
<TR>
<TH>name</TH>
<TH>color</TH>
<TH>unit_price</TH>
</TR>
<!--formatting--><TR>
<TD><!--data--></TD>
<TD><!--data--></TD>
<TD><!--data--></TD>
</TR><!--/formatting-->
</TABLE>
<!--DOCUMENT CACHED_OUTPUT_TIMEOUT = 10 -->