[2252] update descriptions of last_ixfr_duration and last_axfr_duration

- revise to understand more easily
- express a failure case instead of using an implement detail as "timer"
- switch the order of last_ixfr_duration and last_axfr_duration

src/bin/xfrin/b10-xfrin.xml

@@ -235,7 +235,7 @@ operation
               <listitem><simpara>
                 An actual zone name or special zone name
                 <quote>_SERVER_</quote> representing the entire server.
-                Zone classes (IN, CH, HS) are mixed and counted so far. But
+                Zone classes (e.g. IN, CH, HS) are mixed and counted so far. But
                 these will be distinguished in future release.
                 </simpara>
                 <variablelist>
@@ -297,22 +297,22 @@ operation
                   </varlistentry>
 
                   <varlistentry>
-                    <term>last_ixfr_duration</term>
+                    <term>last_axfr_duration</term>
                     <listitem><simpara>
-                      Duration of the last IXFR. 0.0 means no successful IXFR done
-                      in greater than or equal to a microsecond. If a started
-                      timer is never stopped because of failure, start time of
-                      duration will be reset next time.
+                      Duration in seconds of the last successful AXFR.  0.0
+                      means no successful AXFR done or means a successful AXFR
+                      done in less than a microsecond.  If an AXFR is aborted
+                      due to some failure, this duration won't be updated.
                     </simpara></listitem>
                   </varlistentry>
 
                   <varlistentry>
-                    <term>last_axfr_duration</term>
+                    <term>last_ixfr_duration</term>
                     <listitem><simpara>
-                      Duration of the last AXFR. 0.0 means no successful AXFR done
-                      in greater than or equal to a microsecond. If a started
-                      timer is never stopped because of failure, start time of
-                      duration will be reset next time.
+                      Duration in seconds of the last successful IXFR.  0.0
+                      means no successful IXFR done or means a successful IXFR
+                      done in less than a microsecond.  If an IXFR is aborted
+                      due to some failure, this duration won't be updated.
                     </simpara></listitem>
                   </varlistentry>
 

src/bin/xfrin/xfrin.spec

@@ -189,20 +189,20 @@
               "item_description": "Number of zone transfer requests failed"
             },
             {
-              "item_name": "last_ixfr_duration",
+              "item_name": "last_axfr_duration",
               "item_type": "real",
               "item_optional": false,
               "item_default": 0.0,
-              "item_title": "Last IXFR duration",
-              "item_description": "Duration of the last IXFR. 0.0 means no successful IXFR done in greater than or equal to a microsecond. If a started timer is never stopped because of failure, start time of duration will be reset next time."
+              "item_title": "Last AXFR duration",
+              "item_description": "Duration in seconds of the last successful AXFR.  0.0 means no successful AXFR done or means a successful AXFR done in less than a microsecond.  If an AXFR is aborted due to some failure, this duration won't be updated."
             },
             {
-              "item_name": "last_axfr_duration",
+              "item_name": "last_ixfr_duration",
               "item_type": "real",
               "item_optional": false,
               "item_default": 0.0,
-              "item_title": "Last AXFR duration",
-              "item_description": "Duration of the last AXFR. 0.0 means no successful AXFR done in greater than or equal to a microsecond. If a started timer is never stopped because of failure, start time of duration will be reset next time."
+              "item_title": "Last IXFR duration",
+              "item_description": "Duration in seconds of the last successful IXFR.  0.0 means no successful IXFR done or means a successful IXFR done in less than a microsecond.  If an IXFR is aborted due to some failure, this duration won't be updated."
             }
           ]
         }