made logging performance drain obvious

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git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@352730 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/xdocs/faq.xml

@@ -2,6 +2,19 @@
 <!DOCTYPE faqs PUBLIC "-//APACHE//DTD FAQ V1.1//EN" "./dtd/faq-v11.dtd">
 
 <faqs title="Frequently Asked Questions">
+    <faq>
+        <question>
+          Why is reading a simple sheet taking so long?
+        </question>
+        <answer>
+          You've probably enabled logging.  Logging is intended only for 
+          autopsie style debugging.  Having it enabled will reduce performance
+          by a factor of at least 100.  Logging is helpful for understanding 
+          why POI can't read some file or developing POI itself.  Important
+          errors are thrown as exceptions, which means you probably don't need
+          logging.
+        </answer>
+    </faq>
     <faq>
         <question>
           What is the HSSF "eventmodel"?

src/documentation/xdocs/utils/logging.xml

@@ -7,6 +7,7 @@
   <subtitle>Overview</subtitle>
   <authors>
    <person name="Nicola Ken Barozzi" email="nicolaken@apache.org"/>     
+   <person name="Andrew C. Oliver" email="acoliver@apache.org"/>     
   </authors>
  </header>
 
@@ -15,7 +16,11 @@
 
   <p>
     Logging in POI is used only as a debugging mechanism, not a normal runtime
-    logging system.
+    logging system.  Logging is ONLY for autopsie type debugging, and should 
+    NEVER be enabled on a production system.  Enabling logging will reduce 
+    performance by at least a factor of 100.  If you are not developing 
+    POI or trying to debug why POI isn't reading a file correctly, then DO 
+    NOT enable logging.  You've been warned. 
   </p>
 
   <p>