[Hyperic-hq-discuss] hq r13076 - trunk/src/org/hyperic/hq/measurement/server/mbean

[<sc...@hy...>]

Author: scottmf
Date: 2009-04-27 14:10:01 -0700 (Mon, 27 Apr 2009)
New Revision: 13076
URL: http://svn.hyperic.org/?view=rev&root=Hyperic+HQ&revision=13076

Modified:
   trunk/src/org/hyperic/hq/measurement/server/mbean/AvailabilityCheckService.java
Log:
added notes about the synchronization in the backfiller

Modified: trunk/src/org/hyperic/hq/measurement/server/mbean/AvailabilityCheckService.java
===================================================================
--- trunk/src/org/hyperic/hq/measurement/server/mbean/AvailabilityCheckService.java	2009-04-27 20:50:30 UTC (rev 13075)
+++ trunk/src/org/hyperic/hq/measurement/server/mbean/AvailabilityCheckService.java	2009-04-27 21:10:01 UTC (rev 13076)
@@ -113,6 +113,10 @@
         return TimingVoodoo.roundDownTime(begin, measInterval);
     }
 
+    /**
+     * Since this method is called from the synchronized block in hitInSession()
+     * please see the associated NOTE.
+     */
     private Collection getDownPlatforms(Date lDate) {
         final boolean debug = _log.isDebugEnabled();
         AvailabilityCache cache = AvailabilityCache.getInstance();
@@ -196,6 +200,13 @@
             }
         }
         try {
+            // PLEASE NOTE: This synchronized block directly affects the
+            // throughput of the availability metrics, while this lock is
+            // active no availability metric will be inserted.  This is to
+            // ensure the backfilled points will not be inserted after the
+            // associated AVAIL_UP value from the agent.
+            // The code must be extremely efficient or else it will have
+            // a big impact on the performance of availability insertion.
             synchronized (cache) {
                 Collection downPlatforms = getDownPlatforms(lDate);
                 List backfillList = getBackfillPts(downPlatforms, current);
@@ -208,6 +219,10 @@
         }
     }
     
+    /**
+     * Since this method is called from the synchronized block in hitInSession()
+     * please see the associated NOTE.
+     */
     private void backfillAvails(List backfillList) {
         final boolean debug = _log.isDebugEnabled();
         final AvailabilityManagerLocal availMan =