debug logging

src/java/org/apache/cassandra/db/compaction/AbstractCompactionTask.java

@@ -84,4 +84,9 @@ public abstract class AbstractCompactionTask
     // Can be overriden for action that need to be performed if the task won't
     // execute (if sstable can't be marked successfully)
     protected void cancel() {}
+
+    public String toString()
+    {
+        return "CompactionTask(" + sstables + ")";
+    }
 }

src/java/org/apache/cassandra/db/compaction/CompactionManager.java

@@ -111,6 +111,10 @@ public class CompactionManager implements CompactionManagerMBean
      */
     public Future<Integer> submitBackground(final ColumnFamilyStore cfs)
     {
+        logger.debug("Scheduling a background task check for {}.{} with {}",
+                     new Object[] {cfs.table.name,
+                                   cfs.columnFamily,
+                                   cfs.getCompactionStrategy().getClass().getSimpleName()});
         Callable<Integer> callable = new Callable<Integer>()
         {
             public Integer call() throws IOException
@@ -118,16 +122,24 @@ public class CompactionManager implements CompactionManagerMBean
                 compactionLock.readLock().lock();
                 try
                 {
+                    logger.debug("Checking {}.{}", cfs.table.name, cfs.columnFamily); // log after we get the lock so we can see delays from that if any
                     if (!cfs.isValid())
+                    {
+                        logger.debug("Aborting compaction for dropped CF");
                         return 0;
+                    }
 
                     boolean taskExecuted = false;
                     AbstractCompactionStrategy strategy = cfs.getCompactionStrategy();
                     List<AbstractCompactionTask> tasks = strategy.getBackgroundTasks(getDefaultGcBefore(cfs));
+                    logger.debug("{} minor compaction tasks available", tasks.size());
                     for (AbstractCompactionTask task : tasks)
                     {
                         if (!task.markSSTablesForCompaction())
+                        {
+                            logger.debug("Skipping {}; sstables are busy", task);
                             continue;
+                        }
 
                         taskExecuted = true;
                         try

src/java/org/apache/cassandra/db/compaction/LeveledManifest.java

@@ -448,13 +448,17 @@ public class LeveledManifest
     public synchronized int getEstimatedTasks()
     {
         long tasks = 0;
+        long[] estimated = new long[generations.length];
+
         for (int i = generations.length - 1; i >= 0; i--)
         {
             List<SSTableReader> sstables = generations[i];
-            long n = Math.max(0L, SSTableReader.getTotalBytes(sstables) - maxBytesForLevel(i)) / (maxSSTableSizeInMB * 1024 * 1024);
-            logger.debug("Estimating " + n + " compaction tasks in level " + i);
-            tasks += n;
+            estimated[i] = Math.max(0L, SSTableReader.getTotalBytes(sstables) - maxBytesForLevel(i)) / (maxSSTableSizeInMB * 1024 * 1024);
+            tasks += estimated[i];
         }
+
+        logger.debug("Estimating {} compactions to do for {}.{}",
+                     new Object[] {Arrays.asList(estimated), cfs.table.name, cfs.columnFamily});
         return Ints.checkedCast(tasks);
     }
 }

src/java/org/apache/cassandra/db/compaction/SizeTieredCompactionStrategy.java

@@ -53,11 +53,12 @@ public class SizeTieredCompactionStrategy extends AbstractCompactionStrategy
         if (cfs.isCompactionDisabled())
         {
             logger.debug("Compaction is currently disabled.");
-            return Collections.<AbstractCompactionTask>emptyList();
+            return Collections.emptyList();
         }
 
         List<AbstractCompactionTask> tasks = new LinkedList<AbstractCompactionTask>();
         List<List<SSTableReader>> buckets = getBuckets(createSSTableAndLengthPairs(cfs.getSSTables()), minSSTableSize);
+        logger.debug("Compaction buckets are {}", buckets);
 
         for (List<SSTableReader> bucket : buckets)
         {