merge from 0.6

git-svn-id: https://svn.apache.org/repos/asf/cassandra/branches/cassandra-0.7@1071786 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -5,7 +5,10 @@
  * fixes for cache save/load (CASSANDRA-2172, -2174)
  * Handle whole-row deletions in CFOutputFormat (CASSANDRA-2014)
  * Make memtable_flush_writers flush in parallel (CASSANDRA-2178)
- * refactor stress.py to have only one copy of the format string used for creating row keys (CASSANDRA-2108)
+ * make key cache preheating default to false; enable with
+   -Dcompaction_preheat_key_cache=true (CASSANDRA-2175)
+ * refactor stress.py to have only one copy of the format string 
+   used for creating row keys (CASSANDRA-2108)
 
 
 0.7.2

conf/cassandra.yaml

@@ -226,6 +226,11 @@ column_index_size_in_kb: 64
 # will be logged specifying the row key.
 in_memory_compaction_limit_in_mb: 64
 
+# Track cached row keys during compaction, and re-cache their new
+# positions in the compacted sstable.  Disable if you use really large
+# key caches.
+compaction_preheat_key_cache: true
+
 # Time to wait for a reply from other nodes before failing the command 
 rpc_timeout_in_ms: 10000
 

src/java/org/apache/cassandra/config/Config.java

@@ -107,6 +107,7 @@ public class Config
     public Double reduce_cache_sizes_at = 1.0;
     public double reduce_cache_capacity_to = 0.6;
     public int hinted_handoff_throttle_delay_in_ms = 0;
+    public boolean compaction_preheat_key_cache = true;
 
     public static enum CommitLogSync {
         periodic,

src/java/org/apache/cassandra/config/DatabaseDescriptor.java

@@ -1174,4 +1174,9 @@ public class    DatabaseDescriptor
     {
         return conf.hinted_handoff_throttle_delay_in_ms;
     }
+
+    public static boolean getPreheatKeyCache()
+    {
+        return conf.compaction_preheat_key_cache;
+    }
 }

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

@@ -430,12 +430,15 @@ public class CompactionManager implements CompactionManagerMBean
                 long position = writer.append(row);
                 totalkeysWritten++;
 
-                for (SSTableReader sstable : sstables)
+                if (DatabaseDescriptor.getPreheatKeyCache())
                 {
-                    if (sstable.getCachedPosition(row.key) != null)
+                    for (SSTableReader sstable : sstables)
                     {
-                        cachedKeys.put(row.key, position);
-                        break;
+                        if (sstable.getCachedPosition(row.key) != null)
+                        {
+                            cachedKeys.put(row.key, position);
+                            break;
+                        }
                     }
                 }
             }
@@ -447,7 +450,7 @@ public class CompactionManager implements CompactionManagerMBean
 
         SSTableReader ssTable = writer.closeAndOpenReader(getMaxDataAge(sstables));
         cfs.replaceCompactedSSTables(sstables, Arrays.asList(ssTable));
-        for (Entry<DecoratedKey, Long> entry : cachedKeys.entrySet())
+        for (Entry<DecoratedKey, Long> entry : cachedKeys.entrySet()) // empty if preheat is off
             ssTable.cacheKey(entry.getKey(), entry.getValue());
         submitMinorIfNeeded(cfs);