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Posted to commits@cassandra.apache.org by ma...@apache.org on 2014/12/24 14:09:53 UTC

[1/3] cassandra git commit: Increase bloom filter true positive count on key cache hit

Repository: cassandra
Updated Branches:
  refs/heads/trunk 20ccf46f1 -> c37e7bfbb


Increase bloom filter true positive count on key cache hit

Patch by marcuse; reviewed by thobbs for CASSANDRA-8525


Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/f981bd59
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/f981bd59
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/f981bd59

Branch: refs/heads/trunk
Commit: f981bd5969ad677e3ae6cda832075d94245acd4c
Parents: 5f54285
Author: Marcus Eriksson <ma...@apache.org>
Authored: Mon Dec 22 09:00:04 2014 +0100
Committer: Marcus Eriksson <ma...@apache.org>
Committed: Wed Dec 24 13:57:00 2014 +0100

----------------------------------------------------------------------
 CHANGES.txt                                     |  1 +
 .../cassandra/io/sstable/SSTableReader.java     |  3 ++
 .../cassandra/io/sstable/SSTableReaderTest.java | 36 +++++++++++++++++++-
 3 files changed, 39 insertions(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/cassandra/blob/f981bd59/CHANGES.txt
----------------------------------------------------------------------
diff --git a/CHANGES.txt b/CHANGES.txt
index 57ab5b4..c8cf1d4 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
 2.0.12:
+ * Increase bf true positive count on key cache hit (CASSANDRA-8525)
  * Move MeteredFlusher to its own thread (CASSANDRA-8485)
  * Fix non-distinct results in DISTNCT queries on static columns when
    paging is enabled (CASSANDRA-8087)

http://git-wip-us.apache.org/repos/asf/cassandra/blob/f981bd59/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/io/sstable/SSTableReader.java b/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
index f0e9e65..803c7fa 100644
--- a/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
+++ b/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
@@ -887,7 +887,10 @@ public class SSTableReader extends SSTable implements Closeable
                 RowIndexEntry cachedEntry = keyCache.get(unifiedKey);
                 keyCacheRequest.incrementAndGet();
                 if (cachedEntry != null)
+                {
                     keyCacheHit.incrementAndGet();
+                    bloomFilterTracker.addTruePositive();
+                }
                 return cachedEntry;
             }
             else

http://git-wip-us.apache.org/repos/asf/cassandra/blob/f981bd59/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
----------------------------------------------------------------------
diff --git a/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java b/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
index 427d089..e49e564 100644
--- a/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
+++ b/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
@@ -56,6 +56,7 @@ import org.apache.cassandra.thrift.IndexExpression;
 import org.apache.cassandra.thrift.IndexOperator;
 import org.apache.cassandra.utils.ByteBufferUtil;
 import org.apache.cassandra.utils.Pair;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
 @RunWith(OrderedJUnit4ClassRunner.class)
@@ -204,6 +205,39 @@ public class SSTableReaderTest extends SchemaLoader
     }
 
     @Test
+    public void testGetPositionsKeyCacheStats() throws IOException, ExecutionException, InterruptedException
+    {
+        Keyspace keyspace = Keyspace.open("Keyspace1");
+        ColumnFamilyStore store = keyspace.getColumnFamilyStore("Standard2");
+        CacheService.instance.keyCache.setCapacity(1000);
+
+        // insert data and compact to a single sstable
+        CompactionManager.instance.disableAutoCompaction();
+        for (int j = 0; j < 10; j++)
+        {
+            ByteBuffer key = ByteBufferUtil.bytes(String.valueOf(j));
+            RowMutation rm = new RowMutation("Keyspace1", key);
+            rm.add("Standard2", ByteBufferUtil.bytes("0"), ByteBufferUtil.EMPTY_BYTE_BUFFER, j);
+            rm.apply();
+        }
+        store.forceBlockingFlush();
+        CompactionManager.instance.performMaximal(store);
+
+        SSTableReader sstable = store.getSSTables().iterator().next();
+        sstable.getPosition(k(2), SSTableReader.Operator.EQ);
+        assertEquals(0, sstable.getKeyCacheHit());
+        assertEquals(1, sstable.getBloomFilterTruePositiveCount());
+        sstable.getPosition(k(2), SSTableReader.Operator.EQ);
+        assertEquals(1, sstable.getKeyCacheHit());
+        assertEquals(2, sstable.getBloomFilterTruePositiveCount());
+        sstable.getPosition(k(15), SSTableReader.Operator.EQ);
+        assertEquals(1, sstable.getKeyCacheHit());
+        assertEquals(2, sstable.getBloomFilterTruePositiveCount());
+
+    }
+
+
+    @Test
     public void testPersistentStatisticsWithSecondaryIndex() throws IOException, ExecutionException, InterruptedException
     {
         // Create secondary index and flush to disk
@@ -254,7 +288,7 @@ public class SSTableReaderTest extends SchemaLoader
 
         // test to see if sstable can be opened as expected
         SSTableReader target = SSTableReader.open(desc);
-        Assert.assertEquals(target.getKeySampleSize(), 1);
+        assertEquals(target.getKeySampleSize(), 1);
         Assert.assertArrayEquals(ByteBufferUtil.getArray(firstKey.key), target.getKeySample(0));
         assert target.first.equals(firstKey);
         assert target.last.equals(lastKey);


[2/3] cassandra git commit: Merge branch 'cassandra-2.0' into cassandra-2.1

Posted by ma...@apache.org.
Merge branch 'cassandra-2.0' into cassandra-2.1

Conflicts:
	CHANGES.txt
	test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java


Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/b53fefa7
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/b53fefa7
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/b53fefa7

Branch: refs/heads/trunk
Commit: b53fefa731e326391573e7d24af4420c2a79c303
Parents: 5cff788 f981bd5
Author: Marcus Eriksson <ma...@apache.org>
Authored: Wed Dec 24 14:00:05 2014 +0100
Committer: Marcus Eriksson <ma...@apache.org>
Committed: Wed Dec 24 14:00:05 2014 +0100

----------------------------------------------------------------------
 CHANGES.txt                                     |  1 +
 .../cassandra/io/sstable/SSTableReader.java     |  3 ++
 .../cassandra/io/sstable/SSTableReaderTest.java | 32 +++++++++++++++++++-
 3 files changed, 35 insertions(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/cassandra/blob/b53fefa7/CHANGES.txt
----------------------------------------------------------------------
diff --cc CHANGES.txt
index 64bdb62,c8cf1d4..ec64aa9
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@@ -1,47 -1,5 +1,48 @@@
 -2.0.12:
 +2.1.3
 + * Stress - user defined writes should populate sequentally (CASSANDRA-8524)
 + * Fix regression in SSTableRewriter causing some rows to become unreadable 
 +   during compaction (CASSANDRA-8429)
 + * Run major compactions for repaired/unrepaired in parallel (CASSANDRA-8510)
 + * (cqlsh) Fix compression options in DESCRIBE TABLE output when compression
 +   is disabled (CASSANDRA-8288)
 + * (cqlsh) Fix DESCRIBE output after keyspaces are altered (CASSANDRA-7623)
 + * Make sure we set lastCompactedKey correctly (CASSANDRA-8463)
 + * (cqlsh) Fix output of CONSISTENCY command (CASSANDRA-8507)
 + * (cqlsh) Fixed the handling of LIST statements (CASSANDRA-8370)
 + * Make sstablescrub check leveled manifest again (CASSANDRA-8432)
 + * Check first/last keys in sstable when giving out positions (CASSANDRA-8458)
 + * Disable mmap on Windows (CASSANDRA-6993)
 + * Add missing ConsistencyLevels to cassandra-stress (CASSANDRA-8253)
 + * Add auth support to cassandra-stress (CASSANDRA-7985)
 + * Fix ArrayIndexOutOfBoundsException when generating error message
 +   for some CQL syntax errors (CASSANDRA-8455)
 + * Scale memtable slab allocation logarithmically (CASSANDRA-7882)
 + * cassandra-stress simultaneous inserts over same seed (CASSANDRA-7964)
 + * Reduce cassandra-stress sampling memory requirements (CASSANDRA-7926)
 + * Ensure memtable flush cannot expire commit log entries from its future (CASSANDRA-8383)
 + * Make read "defrag" async to reclaim memtables (CASSANDRA-8459)
 + * Remove tmplink files for offline compactions (CASSANDRA-8321)
 + * Reduce maxHintsInProgress (CASSANDRA-8415)
 + * BTree updates may call provided update function twice (CASSANDRA-8018)
 + * Release sstable references after anticompaction (CASSANDRA-8386)
 + * Handle abort() in SSTableRewriter properly (CASSANDRA-8320)
 + * Fix high size calculations for prepared statements (CASSANDRA-8231)
 + * Centralize shared executors (CASSANDRA-8055)
 + * Fix filtering for CONTAINS (KEY) relations on frozen collection
 +   clustering columns when the query is restricted to a single
 +   partition (CASSANDRA-8203)
 + * Do more aggressive entire-sstable TTL expiry checks (CASSANDRA-8243)
 + * Add more log info if readMeter is null (CASSANDRA-8238)
 + * add check of the system wall clock time at startup (CASSANDRA-8305)
 + * Support for frozen collections (CASSANDRA-7859)
 + * Fix overflow on histogram computation (CASSANDRA-8028)
 + * Have paxos reuse the timestamp generation of normal queries (CASSANDRA-7801)
 + * Fix incremental repair not remove parent session on remote (CASSANDRA-8291)
 + * Improve JBOD disk utilization (CASSANDRA-7386)
 + * Log failed host when preparing incremental repair (CASSANDRA-8228)
 + * Force config client mode in CQLSSTableWriter (CASSANDRA-8281)
 +Merged from 2.0:
+  * Increase bf true positive count on key cache hit (CASSANDRA-8525)
   * Move MeteredFlusher to its own thread (CASSANDRA-8485)
   * Fix non-distinct results in DISTNCT queries on static columns when
     paging is enabled (CASSANDRA-8087)

http://git-wip-us.apache.org/repos/asf/cassandra/blob/b53fefa7/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
----------------------------------------------------------------------

http://git-wip-us.apache.org/repos/asf/cassandra/blob/b53fefa7/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
----------------------------------------------------------------------
diff --cc test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
index 03b5553,e49e564..51588f2
--- a/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
+++ b/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
@@@ -64,14 -50,13 +64,13 @@@ import org.apache.cassandra.dht.Token
  import org.apache.cassandra.io.util.FileDataInput;
  import org.apache.cassandra.io.util.MmappedSegmentedFile;
  import org.apache.cassandra.io.util.SegmentedFile;
 +import org.apache.cassandra.service.CacheService;
  import org.apache.cassandra.service.StorageService;
 -import org.apache.cassandra.thrift.IndexExpression;
 -import org.apache.cassandra.thrift.IndexOperator;
  import org.apache.cassandra.utils.ByteBufferUtil;
  import org.apache.cassandra.utils.Pair;
- 
 +import static org.apache.cassandra.Util.cellname;
  import static org.junit.Assert.assertEquals;
 +import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  
  @RunWith(OrderedJUnit4ClassRunner.class)
@@@ -250,22 -205,55 +249,53 @@@ public class SSTableReaderTest extends 
      }
  
      @Test
 +    public void testPersistentStatisticsWithSecondaryIndex()
 +    {
 +        // Create secondary index and flush to disk
 +        Keyspace keyspace = Keyspace.open("Keyspace1");
 +        ColumnFamilyStore store = keyspace.getColumnFamilyStore("Indexed1");
 +        ByteBuffer key = ByteBufferUtil.bytes(String.valueOf("k1"));
 +        Mutation rm = new Mutation("Keyspace1", key);
 +        rm.add("Indexed1", cellname("birthdate"), ByteBufferUtil.bytes(1L), System.currentTimeMillis());
 +        rm.apply();
 +        store.forceBlockingFlush();
 +
 +        // check if opening and querying works
 +        assertIndexQueryWorks(store);
 +    }
+     public void testGetPositionsKeyCacheStats() throws IOException, ExecutionException, InterruptedException
+     {
+         Keyspace keyspace = Keyspace.open("Keyspace1");
+         ColumnFamilyStore store = keyspace.getColumnFamilyStore("Standard2");
+         CacheService.instance.keyCache.setCapacity(1000);
+ 
+         // insert data and compact to a single sstable
+         CompactionManager.instance.disableAutoCompaction();
+         for (int j = 0; j < 10; j++)
+         {
+             ByteBuffer key = ByteBufferUtil.bytes(String.valueOf(j));
 -            RowMutation rm = new RowMutation("Keyspace1", key);
 -            rm.add("Standard2", ByteBufferUtil.bytes("0"), ByteBufferUtil.EMPTY_BYTE_BUFFER, j);
++            Mutation rm = new Mutation("Keyspace1", key);
++            rm.add("Standard2", cellname("0"), ByteBufferUtil.EMPTY_BYTE_BUFFER, j);
+             rm.apply();
+         }
+         store.forceBlockingFlush();
+         CompactionManager.instance.performMaximal(store);
+ 
+         SSTableReader sstable = store.getSSTables().iterator().next();
+         sstable.getPosition(k(2), SSTableReader.Operator.EQ);
+         assertEquals(0, sstable.getKeyCacheHit());
+         assertEquals(1, sstable.getBloomFilterTruePositiveCount());
+         sstable.getPosition(k(2), SSTableReader.Operator.EQ);
+         assertEquals(1, sstable.getKeyCacheHit());
+         assertEquals(2, sstable.getBloomFilterTruePositiveCount());
+         sstable.getPosition(k(15), SSTableReader.Operator.EQ);
+         assertEquals(1, sstable.getKeyCacheHit());
+         assertEquals(2, sstable.getBloomFilterTruePositiveCount());
+ 
+     }
+ 
  
      @Test
 -    public void testPersistentStatisticsWithSecondaryIndex() throws IOException, ExecutionException, InterruptedException
 -    {
 -        // Create secondary index and flush to disk
 -        Keyspace keyspace = Keyspace.open("Keyspace1");
 -        ColumnFamilyStore store = keyspace.getColumnFamilyStore("Indexed1");
 -        ByteBuffer key = ByteBufferUtil.bytes(String.valueOf("k1"));
 -        RowMutation rm = new RowMutation("Keyspace1", key);
 -        rm.add("Indexed1", ByteBufferUtil.bytes("birthdate"), ByteBufferUtil.bytes(1L), System.currentTimeMillis());
 -        rm.apply();
 -        store.forceBlockingFlush();
 -
 -        // check if opening and querying works
 -        assertIndexQueryWorks(store);
 -    }
 -
 -    @Test
      public void testOpeningSSTable() throws Exception
      {
          String ks = "Keyspace1";


[3/3] cassandra git commit: Merge branch 'cassandra-2.1' into trunk

Posted by ma...@apache.org.
Merge branch 'cassandra-2.1' into trunk


Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/c37e7bfb
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/c37e7bfb
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/c37e7bfb

Branch: refs/heads/trunk
Commit: c37e7bfbbf53a5fd73d0c9d5b36d45641f43024d
Parents: 20ccf46 b53fefa
Author: Marcus Eriksson <ma...@apache.org>
Authored: Wed Dec 24 14:03:24 2014 +0100
Committer: Marcus Eriksson <ma...@apache.org>
Committed: Wed Dec 24 14:05:55 2014 +0100

----------------------------------------------------------------------
 CHANGES.txt                                     |  1 +
 .../io/sstable/format/SSTableReader.java        |  3 ++
 .../cassandra/io/sstable/SSTableReaderTest.java | 32 +++++++++++++++++++-
 3 files changed, 35 insertions(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/cassandra/blob/c37e7bfb/CHANGES.txt
----------------------------------------------------------------------

http://git-wip-us.apache.org/repos/asf/cassandra/blob/c37e7bfb/src/java/org/apache/cassandra/io/sstable/format/SSTableReader.java
----------------------------------------------------------------------
diff --cc src/java/org/apache/cassandra/io/sstable/format/SSTableReader.java
index 41898c8,0000000..482d0cc
mode 100644,000000..100644
--- a/src/java/org/apache/cassandra/io/sstable/format/SSTableReader.java
+++ b/src/java/org/apache/cassandra/io/sstable/format/SSTableReader.java
@@@ -1,1878 -1,0 +1,1881 @@@
 +/*
 + * Licensed to the Apache Software Foundation (ASF) under one
 + * or more contributor license agreements.  See the NOTICE file
 + * distributed with this work for additional information
 + * regarding copyright ownership.  The ASF licenses this file
 + * to you under the Apache License, Version 2.0 (the
 + * "License"); you may not use this file except in compliance
 + * with the License.  You may obtain a copy of the License at
 + *
 + *     http://www.apache.org/licenses/LICENSE-2.0
 + *
 + * Unless required by applicable law or agreed to in writing, software
 + * distributed under the License is distributed on an "AS IS" BASIS,
 + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 + * See the License for the specific language governing permissions and
 + * limitations under the License.
 + */
 +package org.apache.cassandra.io.sstable.format;
 +
 +import java.io.*;
 +import java.nio.ByteBuffer;
 +import java.util.*;
 +import java.util.concurrent.*;
 +import java.util.concurrent.atomic.AtomicBoolean;
 +import java.util.concurrent.atomic.AtomicInteger;
 +import java.util.concurrent.atomic.AtomicLong;
 +
 +import com.google.common.annotations.VisibleForTesting;
 +import com.google.common.base.Predicate;
 +import com.google.common.collect.Iterators;
 +import com.google.common.collect.Ordering;
 +import com.google.common.primitives.Longs;
 +import com.google.common.util.concurrent.RateLimiter;
 +
 +import com.clearspring.analytics.stream.cardinality.CardinalityMergeException;
 +import com.clearspring.analytics.stream.cardinality.ICardinality;
 +import org.apache.cassandra.cache.CachingOptions;
 +import org.apache.cassandra.cache.InstrumentingCache;
 +import org.apache.cassandra.cache.KeyCacheKey;
 +import org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor;
 +import org.apache.cassandra.concurrent.ScheduledExecutors;
 +import org.apache.cassandra.config.*;
 +import org.apache.cassandra.db.*;
 +import org.apache.cassandra.db.columniterator.OnDiskAtomIterator;
 +import org.apache.cassandra.db.commitlog.ReplayPosition;
 +import org.apache.cassandra.db.composites.CellName;
 +import org.apache.cassandra.db.filter.ColumnSlice;
 +import org.apache.cassandra.db.index.SecondaryIndex;
 +import org.apache.cassandra.dht.*;
 +import org.apache.cassandra.io.compress.CompressedRandomAccessReader;
 +import org.apache.cassandra.io.compress.CompressedThrottledReader;
 +import org.apache.cassandra.io.compress.CompressionMetadata;
 +import org.apache.cassandra.io.sstable.*;
 +import org.apache.cassandra.io.sstable.metadata.*;
 +import org.apache.cassandra.io.util.*;
 +import org.apache.cassandra.metrics.RestorableMeter;
 +import org.apache.cassandra.metrics.StorageMetrics;
 +import org.apache.cassandra.service.ActiveRepairService;
 +import org.apache.cassandra.service.CacheService;
 +import org.apache.cassandra.service.StorageService;
 +import org.apache.cassandra.utils.*;
 +import org.apache.cassandra.utils.concurrent.OpOrder;
 +import org.slf4j.Logger;
 +import org.slf4j.LoggerFactory;
 +
 +import static org.apache.cassandra.db.Directories.SECONDARY_INDEX_NAME_SEPARATOR;
 +
 +/**
 + * SSTableReaders are open()ed by Keyspace.onStart; after that they are created by SSTableWriter.renameAndOpen.
 + * Do not re-call open() on existing SSTable files; use the references kept by ColumnFamilyStore post-start instead.
 + */
 +public abstract class SSTableReader extends SSTable
 +{
 +    private static final Logger logger = LoggerFactory.getLogger(SSTableReader.class);
 +
 +    private static final ScheduledThreadPoolExecutor syncExecutor = new ScheduledThreadPoolExecutor(1);
 +    private static final RateLimiter meterSyncThrottle = RateLimiter.create(100.0);
 +
 +    public static final Comparator<SSTableReader> maxTimestampComparator = new Comparator<SSTableReader>()
 +    {
 +        public int compare(SSTableReader o1, SSTableReader o2)
 +        {
 +            long ts1 = o1.getMaxTimestamp();
 +            long ts2 = o2.getMaxTimestamp();
 +            return (ts1 > ts2 ? -1 : (ts1 == ts2 ? 0 : 1));
 +        }
 +    };
 +
 +    public static final Comparator<SSTableReader> sstableComparator = new Comparator<SSTableReader>()
 +    {
 +        public int compare(SSTableReader o1, SSTableReader o2)
 +        {
 +            return o1.first.compareTo(o2.first);
 +        }
 +    };
 +
 +    public static final Ordering<SSTableReader> sstableOrdering = Ordering.from(sstableComparator);
 +
 +    /**
 +     * maxDataAge is a timestamp in local server time (e.g. System.currentTimeMilli) which represents an upper bound
 +     * to the newest piece of data stored in the sstable. In other words, this sstable does not contain items created
 +     * later than maxDataAge.
 +     *
 +     * The field is not serialized to disk, so relying on it for more than what truncate does is not advised.
 +     *
 +     * When a new sstable is flushed, maxDataAge is set to the time of creation.
 +     * When a sstable is created from compaction, maxDataAge is set to max of all merged sstables.
 +     *
 +     * The age is in milliseconds since epoc and is local to this host.
 +     */
 +    public final long maxDataAge;
 +
 +    public enum OpenReason
 +    {
 +        NORMAL,
 +        EARLY,
 +        METADATA_CHANGE
 +    }
 +
 +    public final OpenReason openReason;
 +
 +    // indexfile and datafile: might be null before a call to load()
 +    protected SegmentedFile ifile;
 +    protected SegmentedFile dfile;
 +
 +    protected IndexSummary indexSummary;
 +    protected IFilter bf;
 +
 +    protected final RowIndexEntry.IndexSerializer rowIndexEntrySerializer;
 +
 +    protected InstrumentingCache<KeyCacheKey, RowIndexEntry> keyCache;
 +
 +    protected final BloomFilterTracker bloomFilterTracker = new BloomFilterTracker();
 +
 +    protected final AtomicInteger references = new AtomicInteger(1);
 +    // technically isCompacted is not necessary since it should never be unreferenced unless it is also compacted,
 +    // but it seems like a good extra layer of protection against reference counting bugs to not delete data based on that alone
 +    protected final AtomicBoolean isCompacted = new AtomicBoolean(false);
 +    protected final AtomicBoolean isSuspect = new AtomicBoolean(false);
 +
 +    // not final since we need to be able to change level on a file.
 +    protected volatile StatsMetadata sstableMetadata;
 +
 +    protected final AtomicLong keyCacheHit = new AtomicLong(0);
 +    protected final AtomicLong keyCacheRequest = new AtomicLong(0);
 +
 +    /**
 +     * To support replacing this sstablereader with another object that represents that same underlying sstable, but with different associated resources,
 +     * we build a linked-list chain of replacement, which we synchronise using a shared object to make maintenance of the list across multiple threads simple.
 +     * On close we check if any of the closeable resources differ between any chains either side of us; any that are in neither of the adjacent links (if any) are closed.
 +     * Once we've made this decision we remove ourselves from the linked list, so that anybody behind/ahead will compare against only other still opened resources.
 +     */
 +    protected Object replaceLock = new Object();
 +    protected SSTableReader replacedBy;
 +    private SSTableReader replaces;
 +    private SSTableDeletingTask deletingTask;
 +    private Runnable runOnClose;
 +
 +    @VisibleForTesting
 +    public RestorableMeter readMeter;
 +    protected ScheduledFuture readMeterSyncFuture;
 +
 +    /**
 +     * Calculate approximate key count.
 +     * If cardinality estimator is available on all given sstables, then this method use them to estimate
 +     * key count.
 +     * If not, then this uses index summaries.
 +     *
 +     * @param sstables SSTables to calculate key count
 +     * @return estimated key count
 +     */
 +    public static long getApproximateKeyCount(Collection<SSTableReader> sstables)
 +    {
 +        long count = -1;
 +
 +        // check if cardinality estimator is available for all SSTables
 +        boolean cardinalityAvailable = !sstables.isEmpty() && Iterators.all(sstables.iterator(), new Predicate<SSTableReader>()
 +        {
 +            public boolean apply(SSTableReader sstable)
 +            {
 +                return sstable.descriptor.version.hasNewStatsFile();
 +            }
 +        });
 +
 +        // if it is, load them to estimate key count
 +        if (cardinalityAvailable)
 +        {
 +            boolean failed = false;
 +            ICardinality cardinality = null;
 +            for (SSTableReader sstable : sstables)
 +            {
 +                try
 +                {
 +                    CompactionMetadata metadata = (CompactionMetadata) sstable.descriptor.getMetadataSerializer().deserialize(sstable.descriptor, MetadataType.COMPACTION);
 +                    assert metadata != null : sstable.getFilename();
 +                    if (cardinality == null)
 +                        cardinality = metadata.cardinalityEstimator;
 +                    else
 +                        cardinality = cardinality.merge(metadata.cardinalityEstimator);
 +                }
 +                catch (IOException e)
 +                {
 +                    logger.warn("Reading cardinality from Statistics.db failed.", e);
 +                    failed = true;
 +                    break;
 +                }
 +                catch (CardinalityMergeException e)
 +                {
 +                    logger.warn("Cardinality merge failed.", e);
 +                    failed = true;
 +                    break;
 +                }
 +            }
 +            if (cardinality != null && !failed)
 +                count = cardinality.cardinality();
 +        }
 +
 +        // if something went wrong above or cardinality is not available, calculate using index summary
 +        if (count < 0)
 +        {
 +            for (SSTableReader sstable : sstables)
 +                count += sstable.estimatedKeys();
 +        }
 +        return count;
 +    }
 +
 +    public static SSTableReader open(Descriptor descriptor) throws IOException
 +    {
 +        CFMetaData metadata;
 +        if (descriptor.cfname.contains(SECONDARY_INDEX_NAME_SEPARATOR))
 +        {
 +            int i = descriptor.cfname.indexOf(SECONDARY_INDEX_NAME_SEPARATOR);
 +            String parentName = descriptor.cfname.substring(0, i);
 +            CFMetaData parent = Schema.instance.getCFMetaData(descriptor.ksname, parentName);
 +            ColumnDefinition def = parent.getColumnDefinitionForIndex(descriptor.cfname.substring(i + 1));
 +            metadata = CFMetaData.newIndexMetadata(parent, def, SecondaryIndex.getIndexComparator(parent, def));
 +        }
 +        else
 +        {
 +            metadata = Schema.instance.getCFMetaData(descriptor.ksname, descriptor.cfname);
 +        }
 +        return open(descriptor, metadata);
 +    }
 +
 +    public static SSTableReader open(Descriptor desc, CFMetaData metadata) throws IOException
 +    {
 +        IPartitioner p = desc.cfname.contains(SECONDARY_INDEX_NAME_SEPARATOR)
 +                ? new LocalPartitioner(metadata.getKeyValidator())
 +                : StorageService.getPartitioner();
 +        return open(desc, componentsFor(desc), metadata, p);
 +    }
 +
 +    public static SSTableReader open(Descriptor descriptor, Set<Component> components, CFMetaData metadata, IPartitioner partitioner) throws IOException
 +    {
 +        return open(descriptor, components, metadata, partitioner, true);
 +    }
 +
 +    public static SSTableReader openNoValidation(Descriptor descriptor, Set<Component> components, CFMetaData metadata) throws IOException
 +    {
 +        return open(descriptor, components, metadata, StorageService.getPartitioner(), false);
 +    }
 +
 +    /**
 +     * Open SSTable reader to be used in batch mode(such as sstableloader).
 +     *
 +     * @param descriptor
 +     * @param components
 +     * @param metadata
 +     * @param partitioner
 +     * @return opened SSTableReader
 +     * @throws IOException
 +     */
 +    public static SSTableReader openForBatch(Descriptor descriptor, Set<Component> components, CFMetaData metadata, IPartitioner partitioner) throws IOException
 +    {
 +        // Minimum components without which we can't do anything
 +        assert components.contains(Component.DATA) : "Data component is missing for sstable" + descriptor;
 +        assert components.contains(Component.PRIMARY_INDEX) : "Primary index component is missing for sstable " + descriptor;
 +
 +        Map<MetadataType, MetadataComponent> sstableMetadata = descriptor.getMetadataSerializer().deserialize(descriptor,
 +                EnumSet.of(MetadataType.VALIDATION, MetadataType.STATS));
 +        ValidationMetadata validationMetadata = (ValidationMetadata) sstableMetadata.get(MetadataType.VALIDATION);
 +        StatsMetadata statsMetadata = (StatsMetadata) sstableMetadata.get(MetadataType.STATS);
 +
 +        // Check if sstable is created using same partitioner.
 +        // Partitioner can be null, which indicates older version of sstable or no stats available.
 +        // In that case, we skip the check.
 +        String partitionerName = partitioner.getClass().getCanonicalName();
 +        if (validationMetadata != null && !partitionerName.equals(validationMetadata.partitioner))
 +        {
 +            logger.error(String.format("Cannot open %s; partitioner %s does not match system partitioner %s.  Note that the default partitioner starting with Cassandra 1.2 is Murmur3Partitioner, so you will need to edit that to match your old partitioner if upgrading.",
 +                    descriptor, validationMetadata.partitioner, partitionerName));
 +            System.exit(1);
 +        }
 +
 +        logger.info("Opening {} ({} bytes)", descriptor, new File(descriptor.filenameFor(Component.DATA)).length());
 +        SSTableReader sstable = internalOpen(descriptor, components, metadata, partitioner, System.currentTimeMillis(),
 +                statsMetadata, OpenReason.NORMAL);
 +
 +        // special implementation of load to use non-pooled SegmentedFile builders
 +        SegmentedFile.Builder ibuilder = new BufferedSegmentedFile.Builder();
 +        SegmentedFile.Builder dbuilder = sstable.compression
 +                ? new CompressedSegmentedFile.Builder(null)
 +                : new BufferedSegmentedFile.Builder();
 +        if (!sstable.loadSummary(ibuilder, dbuilder))
 +            sstable.buildSummary(false, ibuilder, dbuilder, false, Downsampling.BASE_SAMPLING_LEVEL);
 +        sstable.ifile = ibuilder.complete(sstable.descriptor.filenameFor(Component.PRIMARY_INDEX));
 +        sstable.dfile = dbuilder.complete(sstable.descriptor.filenameFor(Component.DATA));
 +        sstable.bf = FilterFactory.AlwaysPresent;
 +
 +        return sstable;
 +    }
 +
 +    private static SSTableReader open(Descriptor descriptor,
 +                                      Set<Component> components,
 +                                      CFMetaData metadata,
 +                                      IPartitioner partitioner,
 +                                      boolean validate) throws IOException
 +    {
 +        // Minimum components without which we can't do anything
 +        assert components.contains(Component.DATA) : "Data component is missing for sstable" + descriptor;
 +        assert components.contains(Component.PRIMARY_INDEX) : "Primary index component is missing for sstable " + descriptor;
 +
 +        Map<MetadataType, MetadataComponent> sstableMetadata = descriptor.getMetadataSerializer().deserialize(descriptor,
 +                EnumSet.of(MetadataType.VALIDATION, MetadataType.STATS));
 +        ValidationMetadata validationMetadata = (ValidationMetadata) sstableMetadata.get(MetadataType.VALIDATION);
 +        StatsMetadata statsMetadata = (StatsMetadata) sstableMetadata.get(MetadataType.STATS);
 +
 +        // Check if sstable is created using same partitioner.
 +        // Partitioner can be null, which indicates older version of sstable or no stats available.
 +        // In that case, we skip the check.
 +        String partitionerName = partitioner.getClass().getCanonicalName();
 +        if (validationMetadata != null && !partitionerName.equals(validationMetadata.partitioner))
 +        {
 +            logger.error(String.format("Cannot open %s; partitioner %s does not match system partitioner %s.  Note that the default partitioner starting with Cassandra 1.2 is Murmur3Partitioner, so you will need to edit that to match your old partitioner if upgrading.",
 +                    descriptor, validationMetadata.partitioner, partitionerName));
 +            System.exit(1);
 +        }
 +
 +        logger.info("Opening {} ({} bytes)", descriptor, new File(descriptor.filenameFor(Component.DATA)).length());
 +        SSTableReader sstable = internalOpen(descriptor, components, metadata, partitioner, System.currentTimeMillis(),
 +                statsMetadata, OpenReason.NORMAL);
 +
 +        // load index and filter
 +        long start = System.nanoTime();
 +        sstable.load(validationMetadata);
 +        logger.debug("INDEX LOAD TIME for {}: {} ms.", descriptor, TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start));
 +
 +        if (validate)
 +            sstable.validate();
 +
 +        if (sstable.getKeyCache() != null)
 +            logger.debug("key cache contains {}/{} keys", sstable.getKeyCache().size(), sstable.getKeyCache().getCapacity());
 +
 +        return sstable;
 +    }
 +
 +    public static void logOpenException(Descriptor descriptor, IOException e)
 +    {
 +        if (e instanceof FileNotFoundException)
 +            logger.error("Missing sstable component in {}; skipped because of {}", descriptor, e.getMessage());
 +        else
 +            logger.error("Corrupt sstable {}; skipped", descriptor, e);
 +    }
 +
 +    public static Collection<SSTableReader> openAll(Set<Map.Entry<Descriptor, Set<Component>>> entries,
 +                                                    final CFMetaData metadata,
 +                                                    final IPartitioner partitioner)
 +    {
 +        final Collection<SSTableReader> sstables = new LinkedBlockingQueue<>();
 +
 +        ExecutorService executor = DebuggableThreadPoolExecutor.createWithFixedPoolSize("SSTableBatchOpen", FBUtilities.getAvailableProcessors());
 +        for (final Map.Entry<Descriptor, Set<Component>> entry : entries)
 +        {
 +            Runnable runnable = new Runnable()
 +            {
 +                public void run()
 +                {
 +                    SSTableReader sstable;
 +                    try
 +                    {
 +                        sstable = open(entry.getKey(), entry.getValue(), metadata, partitioner);
 +                    }
 +                    catch (IOException ex)
 +                    {
 +                        logger.error("Corrupt sstable {}; skipped", entry, ex);
 +                        return;
 +                    }
 +                    sstables.add(sstable);
 +                }
 +            };
 +            executor.submit(runnable);
 +        }
 +
 +        executor.shutdown();
 +        try
 +        {
 +            executor.awaitTermination(7, TimeUnit.DAYS);
 +        }
 +        catch (InterruptedException e)
 +        {
 +            throw new AssertionError(e);
 +        }
 +
 +        return sstables;
 +
 +    }
 +
 +    /**
 +     * Open a RowIndexedReader which already has its state initialized (by SSTableWriter).
 +     */
 +    public static SSTableReader internalOpen(Descriptor desc,
 +                                      Set<Component> components,
 +                                      CFMetaData metadata,
 +                                      IPartitioner partitioner,
 +                                      SegmentedFile ifile,
 +                                      SegmentedFile dfile,
 +                                      IndexSummary isummary,
 +                                      IFilter bf,
 +                                      long maxDataAge,
 +                                      StatsMetadata sstableMetadata,
 +                                      OpenReason openReason)
 +    {
 +        assert desc != null && partitioner != null && ifile != null && dfile != null && isummary != null && bf != null && sstableMetadata != null;
 +
 +        SSTableReader reader = internalOpen(desc, components, metadata, partitioner, maxDataAge, sstableMetadata, openReason);
 +
 +        reader.bf = bf;
 +        reader.ifile = ifile;
 +        reader.dfile = dfile;
 +        reader.indexSummary = isummary;
 +
 +        return reader;
 +    }
 +
 +
 +    private static SSTableReader internalOpen(final Descriptor descriptor,
 +                                            Set<Component> components,
 +                                            CFMetaData metadata,
 +                                            IPartitioner partitioner,
 +                                            Long maxDataAge,
 +                                            StatsMetadata sstableMetadata,
 +                                            OpenReason openReason)
 +    {
 +        Factory readerFactory = descriptor.getFormat().getReaderFactory();
 +
 +        return readerFactory.open(descriptor, components, metadata, partitioner, maxDataAge, sstableMetadata, openReason);
 +    }
 +
 +    protected SSTableReader(final Descriptor desc,
 +                            Set<Component> components,
 +                            CFMetaData metadata,
 +                            IPartitioner partitioner,
 +                            long maxDataAge,
 +                            StatsMetadata sstableMetadata,
 +                            OpenReason openReason)
 +    {
 +        super(desc, components, metadata, partitioner);
 +        this.sstableMetadata = sstableMetadata;
 +        this.maxDataAge = maxDataAge;
 +        this.openReason = openReason;
 +
 +        this.rowIndexEntrySerializer = descriptor.version.getSSTableFormat().getIndexSerializer(metadata);
 +
 +        deletingTask = new SSTableDeletingTask(this);
 +
 +        // Don't track read rates for tables in the system keyspace.  Also don't track reads for special operations (like early open)
 +        // this is to avoid overflowing the executor queue (see CASSANDRA-8066)
 +        if (SystemKeyspace.NAME.equals(desc.ksname) || openReason != OpenReason.NORMAL)
 +        {
 +            readMeter = null;
 +            readMeterSyncFuture = null;
 +            return;
 +        }
 +
 +        readMeter = SystemKeyspace.getSSTableReadMeter(desc.ksname, desc.cfname, desc.generation);
 +        // sync the average read rate to system.sstable_activity every five minutes, starting one minute from now
 +        readMeterSyncFuture = syncExecutor.scheduleAtFixedRate(new Runnable()
 +        {
 +            public void run()
 +            {
 +                if (!isCompacted.get())
 +                {
 +                    meterSyncThrottle.acquire();
 +                    SystemKeyspace.persistSSTableReadMeter(desc.ksname, desc.cfname, desc.generation, readMeter);
 +                }
 +            }
 +        }, 1, 5, TimeUnit.MINUTES);
 +    }
 +
 +    public static long getTotalBytes(Iterable<SSTableReader> sstables)
 +    {
 +        long sum = 0;
 +        for (SSTableReader sstable : sstables)
 +        {
 +            sum += sstable.onDiskLength();
 +        }
 +        return sum;
 +    }
 +
 +    private void tidy(boolean release)
 +    {
 +        if (readMeterSyncFuture != null)
 +            readMeterSyncFuture.cancel(false);
 +
 +        if (references.get() != 0)
 +        {
 +            throw new IllegalStateException("SSTable is not fully released (" + references.get() + " references)");
 +        }
 +
 +        synchronized (replaceLock)
 +        {
 +            boolean closeBf = true, closeSummary = true, closeFiles = true, deleteFiles = isCompacted.get();
 +
 +            if (replacedBy != null)
 +            {
 +                closeBf = replacedBy.bf != bf;
 +                closeSummary = replacedBy.indexSummary != indexSummary;
 +                closeFiles = replacedBy.dfile != dfile;
 +                // if the replacement sstablereader uses a different path, clean up our paths
 +                deleteFiles = !dfile.path.equals(replacedBy.dfile.path);
 +            }
 +
 +            if (replaces != null)
 +            {
 +                closeBf &= replaces.bf != bf;
 +                closeSummary &= replaces.indexSummary != indexSummary;
 +                closeFiles &= replaces.dfile != dfile;
 +                deleteFiles &= !dfile.path.equals(replaces.dfile.path);
 +            }
 +
 +            boolean deleteAll = false;
 +            if (release && isCompacted.get())
 +            {
 +                assert replacedBy == null;
 +                if (replaces != null && !deleteFiles)
 +                {
 +                    replaces.replacedBy = null;
 +                    replaces.deletingTask = deletingTask;
 +                    replaces.markObsolete();
 +                }
 +                else
 +                {
 +                    deleteAll = true;
 +                }
 +            }
 +            else
 +            {
 +                if (replaces != null)
 +                    replaces.replacedBy = replacedBy;
 +                if (replacedBy != null)
 +                    replacedBy.replaces = replaces;
 +            }
 +
 +            scheduleTidy(closeBf, closeSummary, closeFiles, deleteFiles, deleteAll);
 +        }
 +    }
 +
 +    private void scheduleTidy(final boolean closeBf, final boolean closeSummary, final boolean closeFiles, final boolean deleteFiles, final boolean deleteAll)
 +    {
 +        if (references.get() != 0)
 +            throw new IllegalStateException("SSTable is not fully released (" + references.get() + " references)");
 +
 +        final ColumnFamilyStore cfs = Schema.instance.getColumnFamilyStoreInstance(metadata.cfId);
 +        final OpOrder.Barrier barrier;
 +        if (cfs != null)
 +        {
 +            barrier = cfs.readOrdering.newBarrier();
 +            barrier.issue();
 +        }
 +        else
 +            barrier = null;
 +
 +        ScheduledExecutors.nonPeriodicTasks.execute(new Runnable()
 +        {
 +            public void run()
 +            {
 +                if (barrier != null)
 +                    barrier.await();
 +                if (closeBf)
 +                    bf.close();
 +                if (closeSummary)
 +                    indexSummary.close();
 +                if (closeFiles)
 +                {
 +                    ifile.cleanup();
 +                    dfile.cleanup();
 +                }
 +                if (runOnClose != null)
 +                    runOnClose.run();
 +                if (deleteAll)
 +                {
 +                    /**
 +                     * Do the OS a favour and suggest (using fadvice call) that we
 +                     * don't want to see pages of this SSTable in memory anymore.
 +                     *
 +                     * NOTE: We can't use madvice in java because it requires the address of
 +                     * the mapping, so instead we always open a file and run fadvice(fd, 0, 0) on it
 +                     */
 +                    dropPageCache();
 +                    deletingTask.run();
 +                }
 +                else if (deleteFiles)
 +                {
 +                    FileUtils.deleteWithConfirm(new File(dfile.path));
 +                    FileUtils.deleteWithConfirm(new File(ifile.path));
 +                }
 +            }
 +        });
 +    }
 +
 +    public boolean equals(Object that)
 +    {
 +        return that instanceof SSTableReader && ((SSTableReader) that).descriptor.equals(this.descriptor);
 +    }
 +
 +    public int hashCode()
 +    {
 +        return this.descriptor.hashCode();
 +    }
 +
 +    public String getFilename()
 +    {
 +        return dfile.path;
 +    }
 +
 +    public String getIndexFilename()
 +    {
 +        return ifile.path;
 +    }
 +
 +    public void setTrackedBy(DataTracker tracker)
 +    {
 +        deletingTask.setTracker(tracker);
 +        // under normal operation we can do this at any time, but SSTR is also used outside C* proper,
 +        // e.g. by BulkLoader, which does not initialize the cache.  As a kludge, we set up the cache
 +        // here when we know we're being wired into the rest of the server infrastructure.
 +        keyCache = CacheService.instance.keyCache;
 +    }
 +
 +    private void load(ValidationMetadata validation) throws IOException
 +    {
 +        if (metadata.getBloomFilterFpChance() == 1.0)
 +        {
 +            // bf is disabled.
 +            load(false, true);
 +            bf = FilterFactory.AlwaysPresent;
 +        }
 +        else if (!components.contains(Component.FILTER) || validation == null)
 +        {
 +            // bf is enabled, but filter component is missing.
 +            load(true, true);
 +        }
 +        else if (validation.bloomFilterFPChance != metadata.getBloomFilterFpChance())
 +        {
 +            // bf fp chance in sstable metadata and it has changed since compaction.
 +            load(true, true);
 +        }
 +        else
 +        {
 +            // bf is enabled and fp chance matches the currently configured value.
 +            load(false, true);
 +            loadBloomFilter();
 +        }
 +    }
 +
 +    /**
 +     * Load bloom filter from Filter.db file.
 +     *
 +     * @throws IOException
 +     */
 +    private void loadBloomFilter() throws IOException
 +    {
 +        DataInputStream stream = null;
 +        try
 +        {
 +            stream = new DataInputStream(new BufferedInputStream(new FileInputStream(descriptor.filenameFor(Component.FILTER))));
 +            bf = FilterFactory.deserialize(stream, true);
 +        }
 +        finally
 +        {
 +            FileUtils.closeQuietly(stream);
 +        }
 +    }
 +
 +    /**
 +     * Loads ifile, dfile and indexSummary, and optionally recreates the bloom filter.
 +     * @param saveSummaryIfCreated for bulk loading purposes, if the summary was absent and needed to be built, you can
 +     *                             avoid persisting it to disk by setting this to false
 +     */
 +    private void load(boolean recreateBloomFilter, boolean saveSummaryIfCreated) throws IOException
 +    {
 +        SegmentedFile.Builder ibuilder = SegmentedFile.getBuilder(DatabaseDescriptor.getIndexAccessMode());
 +        SegmentedFile.Builder dbuilder = compression
 +                ? SegmentedFile.getCompressedBuilder()
 +                : SegmentedFile.getBuilder(DatabaseDescriptor.getDiskAccessMode());
 +
 +        boolean summaryLoaded = loadSummary(ibuilder, dbuilder);
 +        if (recreateBloomFilter || !summaryLoaded)
 +            buildSummary(recreateBloomFilter, ibuilder, dbuilder, summaryLoaded, Downsampling.BASE_SAMPLING_LEVEL);
 +
 +        ifile = ibuilder.complete(descriptor.filenameFor(Component.PRIMARY_INDEX));
 +        dfile = dbuilder.complete(descriptor.filenameFor(Component.DATA));
 +        if (saveSummaryIfCreated && (recreateBloomFilter || !summaryLoaded)) // save summary information to disk
 +            saveSummary(ibuilder, dbuilder);
 +    }
 +
 +    /**
 +     * Build index summary(and optionally bloom filter) by reading through Index.db file.
 +     *
 +     * @param recreateBloomFilter true if recreate bloom filter
 +     * @param ibuilder
 +     * @param dbuilder
 +     * @param summaryLoaded true if index summary is already loaded and not need to build again
 +     * @throws IOException
 +     */
 +    private void buildSummary(boolean recreateBloomFilter, SegmentedFile.Builder ibuilder, SegmentedFile.Builder dbuilder, boolean summaryLoaded, int samplingLevel) throws IOException
 +    {
 +        // we read the positions in a BRAF so we don't have to worry about an entry spanning a mmap boundary.
 +        RandomAccessReader primaryIndex = RandomAccessReader.open(new File(descriptor.filenameFor(Component.PRIMARY_INDEX)));
 +
 +        try
 +        {
 +            long indexSize = primaryIndex.length();
 +            long histogramCount = sstableMetadata.estimatedRowSize.count();
 +            long estimatedKeys = histogramCount > 0 && !sstableMetadata.estimatedRowSize.isOverflowed()
 +                    ? histogramCount
 +                    : estimateRowsFromIndex(primaryIndex); // statistics is supposed to be optional
 +
 +            if (recreateBloomFilter)
 +                bf = FilterFactory.getFilter(estimatedKeys, metadata.getBloomFilterFpChance(), true);
 +
 +            IndexSummaryBuilder summaryBuilder = null;
 +            if (!summaryLoaded)
 +                summaryBuilder = new IndexSummaryBuilder(estimatedKeys, metadata.getMinIndexInterval(), samplingLevel);
 +
 +            long indexPosition;
 +            RowIndexEntry.IndexSerializer rowIndexSerializer = descriptor.getFormat().getIndexSerializer(metadata);
 +
 +            while ((indexPosition = primaryIndex.getFilePointer()) != indexSize)
 +            {
 +                ByteBuffer key = ByteBufferUtil.readWithShortLength(primaryIndex);
 +                RowIndexEntry indexEntry = rowIndexSerializer.deserialize(primaryIndex, descriptor.version);
 +                DecoratedKey decoratedKey = partitioner.decorateKey(key);
 +                if (first == null)
 +                    first = decoratedKey;
 +                last = decoratedKey;
 +
 +                if (recreateBloomFilter)
 +                    bf.add(decoratedKey.getKey());
 +
 +                // if summary was already read from disk we don't want to re-populate it using primary index
 +                if (!summaryLoaded)
 +                {
 +                    summaryBuilder.maybeAddEntry(decoratedKey, indexPosition);
 +                    ibuilder.addPotentialBoundary(indexPosition);
 +                    dbuilder.addPotentialBoundary(indexEntry.position);
 +                }
 +            }
 +
 +            if (!summaryLoaded)
 +                indexSummary = summaryBuilder.build(partitioner);
 +        }
 +        finally
 +        {
 +            FileUtils.closeQuietly(primaryIndex);
 +        }
 +
 +        first = getMinimalKey(first);
 +        last = getMinimalKey(last);
 +    }
 +
 +    /**
 +     * Load index summary from Summary.db file if it exists.
 +     *
 +     * if loaded index summary has different index interval from current value stored in schema,
 +     * then Summary.db file will be deleted and this returns false to rebuild summary.
 +     *
 +     * @param ibuilder
 +     * @param dbuilder
 +     * @return true if index summary is loaded successfully from Summary.db file.
 +     */
 +    public boolean loadSummary(SegmentedFile.Builder ibuilder, SegmentedFile.Builder dbuilder)
 +    {
 +        File summariesFile = new File(descriptor.filenameFor(Component.SUMMARY));
 +        if (!summariesFile.exists())
 +            return false;
 +
 +        DataInputStream iStream = null;
 +        try
 +        {
 +            iStream = new DataInputStream(new FileInputStream(summariesFile));
 +            indexSummary = IndexSummary.serializer.deserialize(iStream, partitioner, descriptor.version.hasSamplingLevel(), metadata.getMinIndexInterval(), metadata.getMaxIndexInterval());
 +            first = partitioner.decorateKey(ByteBufferUtil.readWithLength(iStream));
 +            last = partitioner.decorateKey(ByteBufferUtil.readWithLength(iStream));
 +            ibuilder.deserializeBounds(iStream);
 +            dbuilder.deserializeBounds(iStream);
 +        }
 +        catch (IOException e)
 +        {
 +            logger.debug("Cannot deserialize SSTable Summary File {}: {}", summariesFile.getPath(), e.getMessage());
 +            // corrupted; delete it and fall back to creating a new summary
 +            FileUtils.closeQuietly(iStream);
 +            // delete it and fall back to creating a new summary
 +            FileUtils.deleteWithConfirm(summariesFile);
 +            return false;
 +        }
 +        finally
 +        {
 +            FileUtils.closeQuietly(iStream);
 +        }
 +
 +        return true;
 +    }
 +
 +    /**
 +     * Save index summary to Summary.db file.
 +     *
 +     * @param ibuilder
 +     * @param dbuilder
 +     */
 +    public void saveSummary(SegmentedFile.Builder ibuilder, SegmentedFile.Builder dbuilder)
 +    {
 +        saveSummary(ibuilder, dbuilder, indexSummary);
 +    }
 +
 +    private void saveSummary(SegmentedFile.Builder ibuilder, SegmentedFile.Builder dbuilder, IndexSummary summary)
 +    {
 +        File summariesFile = new File(descriptor.filenameFor(Component.SUMMARY));
 +        if (summariesFile.exists())
 +            FileUtils.deleteWithConfirm(summariesFile);
 +
 +        DataOutputStreamAndChannel oStream = null;
 +        try
 +        {
 +            oStream = new DataOutputStreamAndChannel(new FileOutputStream(summariesFile));
 +            IndexSummary.serializer.serialize(summary, oStream, descriptor.version.hasSamplingLevel());
 +            ByteBufferUtil.writeWithLength(first.getKey(), oStream);
 +            ByteBufferUtil.writeWithLength(last.getKey(), oStream);
 +            ibuilder.serializeBounds(oStream);
 +            dbuilder.serializeBounds(oStream);
 +        }
 +        catch (IOException e)
 +        {
 +            logger.debug("Cannot save SSTable Summary: ", e);
 +
 +            // corrupted hence delete it and let it load it now.
 +            if (summariesFile.exists())
 +                FileUtils.deleteWithConfirm(summariesFile);
 +        }
 +        finally
 +        {
 +            FileUtils.closeQuietly(oStream);
 +        }
 +    }
 +
 +    public void setReplacedBy(SSTableReader replacement)
 +    {
 +        synchronized (replaceLock)
 +        {
 +            assert replacedBy == null;
 +            replacedBy = replacement;
 +            replacement.replaces = this;
 +            replacement.replaceLock = replaceLock;
 +        }
 +    }
 +
 +    public SSTableReader cloneWithNewStart(DecoratedKey newStart, final Runnable runOnClose)
 +    {
 +        synchronized (replaceLock)
 +        {
 +            assert replacedBy == null;
 +
 +            if (newStart.compareTo(this.first) > 0)
 +            {
 +                if (newStart.compareTo(this.last) > 0)
 +                {
 +                    this.runOnClose = new Runnable()
 +                    {
 +                        public void run()
 +                        {
 +                            CLibrary.trySkipCache(dfile.path, 0, 0);
 +                            CLibrary.trySkipCache(ifile.path, 0, 0);
 +                            runOnClose.run();
 +                        }
 +                    };
 +                }
 +                else
 +                {
 +                    final long dataStart = getPosition(newStart, Operator.GE).position;
 +                    final long indexStart = getIndexScanPosition(newStart);
 +                    this.runOnClose = new Runnable()
 +                    {
 +                        public void run()
 +                        {
 +                            CLibrary.trySkipCache(dfile.path, 0, dataStart);
 +                            CLibrary.trySkipCache(ifile.path, 0, indexStart);
 +                            runOnClose.run();
 +                        }
 +                    };
 +                }
 +            }
 +
 +            SSTableReader replacement = internalOpen(descriptor, components, metadata, partitioner, ifile, dfile, indexSummary.readOnlyClone(), bf, maxDataAge, sstableMetadata,
 +                    openReason == OpenReason.EARLY ? openReason : OpenReason.METADATA_CHANGE);
 +            replacement.readMeterSyncFuture = this.readMeterSyncFuture;
 +            replacement.readMeter = this.readMeter;
 +            replacement.first = this.last.compareTo(newStart) > 0 ? newStart : this.last;
 +            replacement.last = this.last;
 +            setReplacedBy(replacement);
 +            return replacement;
 +        }
 +    }
 +
 +    /**
 +     * Returns a new SSTableReader with the same properties as this SSTableReader except that a new IndexSummary will
 +     * be built at the target samplingLevel.  This (original) SSTableReader instance will be marked as replaced, have
 +     * its DeletingTask removed, and have its periodic read-meter sync task cancelled.
 +     * @param samplingLevel the desired sampling level for the index summary on the new SSTableReader
 +     * @return a new SSTableReader
 +     * @throws IOException
 +     */
 +    public SSTableReader cloneWithNewSummarySamplingLevel(ColumnFamilyStore parent, int samplingLevel) throws IOException
 +    {
 +        synchronized (replaceLock)
 +        {
 +            assert replacedBy == null;
 +
 +            int minIndexInterval = metadata.getMinIndexInterval();
 +            int maxIndexInterval = metadata.getMaxIndexInterval();
 +            double effectiveInterval = indexSummary.getEffectiveIndexInterval();
 +
 +            IndexSummary newSummary;
 +            long oldSize = bytesOnDisk();
 +
 +            // We have to rebuild the summary from the on-disk primary index in three cases:
 +            // 1. The sampling level went up, so we need to read more entries off disk
 +            // 2. The min_index_interval changed (in either direction); this changes what entries would be in the summary
 +            //    at full sampling (and consequently at any other sampling level)
 +            // 3. The max_index_interval was lowered, forcing us to raise the sampling level
 +            if (samplingLevel > indexSummary.getSamplingLevel() || indexSummary.getMinIndexInterval() != minIndexInterval || effectiveInterval > maxIndexInterval)
 +            {
 +                newSummary = buildSummaryAtLevel(samplingLevel);
 +            }
 +            else if (samplingLevel < indexSummary.getSamplingLevel())
 +            {
 +                // we can use the existing index summary to make a smaller one
 +                newSummary = IndexSummaryBuilder.downsample(indexSummary, samplingLevel, minIndexInterval, partitioner);
 +
 +                SegmentedFile.Builder ibuilder = SegmentedFile.getBuilder(DatabaseDescriptor.getIndexAccessMode());
 +                SegmentedFile.Builder dbuilder = compression
 +                        ? SegmentedFile.getCompressedBuilder()
 +                        : SegmentedFile.getBuilder(DatabaseDescriptor.getDiskAccessMode());
 +                saveSummary(ibuilder, dbuilder, newSummary);
 +            }
 +            else
 +            {
 +                throw new AssertionError("Attempted to clone SSTableReader with the same index summary sampling level and " +
 +                        "no adjustments to min/max_index_interval");
 +            }
 +
 +            long newSize = bytesOnDisk();
 +            StorageMetrics.load.inc(newSize - oldSize);
 +            parent.metric.liveDiskSpaceUsed.inc(newSize - oldSize);
 +
 +            SSTableReader replacement = internalOpen(descriptor, components, metadata, partitioner, ifile, dfile, newSummary, bf, maxDataAge, sstableMetadata,
 +                    openReason == OpenReason.EARLY ? openReason : OpenReason.METADATA_CHANGE);
 +            replacement.readMeterSyncFuture = this.readMeterSyncFuture;
 +            replacement.readMeter = this.readMeter;
 +            replacement.first = this.first;
 +            replacement.last = this.last;
 +            setReplacedBy(replacement);
 +            return replacement;
 +        }
 +    }
 +
 +    private IndexSummary buildSummaryAtLevel(int newSamplingLevel) throws IOException
 +    {
 +        // we read the positions in a BRAF so we don't have to worry about an entry spanning a mmap boundary.
 +        RandomAccessReader primaryIndex = RandomAccessReader.open(new File(descriptor.filenameFor(Component.PRIMARY_INDEX)));
 +        try
 +        {
 +            long indexSize = primaryIndex.length();
 +            IndexSummaryBuilder summaryBuilder = new IndexSummaryBuilder(estimatedKeys(), metadata.getMinIndexInterval(), newSamplingLevel);
 +
 +            long indexPosition;
 +            while ((indexPosition = primaryIndex.getFilePointer()) != indexSize)
 +            {
 +                summaryBuilder.maybeAddEntry(partitioner.decorateKey(ByteBufferUtil.readWithShortLength(primaryIndex)), indexPosition);
 +                RowIndexEntry.Serializer.skip(primaryIndex);
 +            }
 +
 +            return summaryBuilder.build(partitioner);
 +        }
 +        finally
 +        {
 +            FileUtils.closeQuietly(primaryIndex);
 +        }
 +    }
 +
 +    public int getIndexSummarySamplingLevel()
 +    {
 +        return indexSummary.getSamplingLevel();
 +    }
 +
 +    public long getIndexSummaryOffHeapSize()
 +    {
 +        return indexSummary.getOffHeapSize();
 +    }
 +
 +    public int getMinIndexInterval()
 +    {
 +        return indexSummary.getMinIndexInterval();
 +    }
 +
 +    public double getEffectiveIndexInterval()
 +    {
 +        return indexSummary.getEffectiveIndexInterval();
 +    }
 +
 +    public void releaseSummary() throws IOException
 +    {
 +        indexSummary.close();
 +        indexSummary = null;
 +    }
 +
 +    private void validate()
 +    {
 +        if (this.first.compareTo(this.last) > 0)
 +            throw new IllegalStateException(String.format("SSTable first key %s > last key %s", this.first, this.last));
 +    }
 +
 +    /**
 +     * Gets the position in the index file to start scanning to find the given key (at most indexInterval keys away,
 +     * modulo downsampling of the index summary).
 +     */
 +    public long getIndexScanPosition(RowPosition key)
 +    {
 +        return getIndexScanPositionFromBinarySearchResult(indexSummary.binarySearch(key), indexSummary);
 +    }
 +
 +    protected static long getIndexScanPositionFromBinarySearchResult(int binarySearchResult, IndexSummary referencedIndexSummary)
 +    {
 +        if (binarySearchResult == -1)
 +            return -1;
 +        else
 +            return referencedIndexSummary.getPosition(getIndexSummaryIndexFromBinarySearchResult(binarySearchResult));
 +    }
 +
 +    protected static int getIndexSummaryIndexFromBinarySearchResult(int binarySearchResult)
 +    {
 +        if (binarySearchResult < 0)
 +        {
 +            // binary search gives us the first index _greater_ than the key searched for,
 +            // i.e., its insertion position
 +            int greaterThan = (binarySearchResult + 1) * -1;
 +            if (greaterThan == 0)
 +                return -1;
 +            return greaterThan - 1;
 +        }
 +        else
 +        {
 +            return binarySearchResult;
 +        }
 +    }
 +
 +    /**
 +     * Returns the compression metadata for this sstable.
 +     * @throws IllegalStateException if the sstable is not compressed
 +     */
 +    public CompressionMetadata getCompressionMetadata()
 +    {
 +        if (!compression)
 +            throw new IllegalStateException(this + " is not compressed");
 +
 +        CompressionMetadata cmd = ((ICompressedFile) dfile).getMetadata();
 +
 +        //We need the parent cf metadata
 +        String cfName = metadata.isSecondaryIndex() ? metadata.getParentColumnFamilyName() : metadata.cfName;
 +        cmd.parameters.setLiveMetadata(Schema.instance.getCFMetaData(metadata.ksName, cfName));
 +
 +        return cmd;
 +    }
 +
 +    /**
 +     * Returns the amount of memory in bytes used off heap by the compression meta-data.
 +     * @return the amount of memory in bytes used off heap by the compression meta-data
 +     */
 +    public long getCompressionMetadataOffHeapSize()
 +    {
 +        if (!compression)
 +            return 0;
 +
 +        return getCompressionMetadata().offHeapSize();
 +    }
 +
 +    /**
 +     * For testing purposes only.
 +     */
 +    public void forceFilterFailures()
 +    {
 +        bf = FilterFactory.AlwaysPresent;
 +    }
 +
 +    public IFilter getBloomFilter()
 +    {
 +        return bf;
 +    }
 +
 +    public long getBloomFilterSerializedSize()
 +    {
 +        return bf.serializedSize();
 +    }
 +
 +    /**
 +     * Returns the amount of memory in bytes used off heap by the bloom filter.
 +     * @return the amount of memory in bytes used off heap by the bloom filter
 +     */
 +    public long getBloomFilterOffHeapSize()
 +    {
 +        return bf.offHeapSize();
 +    }
 +
 +    /**
 +     * @return An estimate of the number of keys in this SSTable based on the index summary.
 +     */
 +    public long estimatedKeys()
 +    {
 +        return indexSummary.getEstimatedKeyCount();
 +    }
 +
 +    /**
 +     * @param ranges
 +     * @return An estimate of the number of keys for given ranges in this SSTable.
 +     */
 +    public long estimatedKeysForRanges(Collection<Range<Token>> ranges)
 +    {
 +        long sampleKeyCount = 0;
 +        List<Pair<Integer, Integer>> sampleIndexes = getSampleIndexesForRanges(indexSummary, ranges);
 +        for (Pair<Integer, Integer> sampleIndexRange : sampleIndexes)
 +            sampleKeyCount += (sampleIndexRange.right - sampleIndexRange.left + 1);
 +
 +        // adjust for the current sampling level: (BSL / SL) * index_interval_at_full_sampling
 +        long estimatedKeys = sampleKeyCount * (Downsampling.BASE_SAMPLING_LEVEL * indexSummary.getMinIndexInterval()) / indexSummary.getSamplingLevel();
 +        return Math.max(1, estimatedKeys);
 +    }
 +
 +    /**
 +     * Returns the number of entries in the IndexSummary.  At full sampling, this is approximately 1/INDEX_INTERVALth of
 +     * the keys in this SSTable.
 +     */
 +    public int getIndexSummarySize()
 +    {
 +        return indexSummary.size();
 +    }
 +
 +    /**
 +     * Returns the approximate number of entries the IndexSummary would contain if it were at full sampling.
 +     */
 +    public int getMaxIndexSummarySize()
 +    {
 +        return indexSummary.getMaxNumberOfEntries();
 +    }
 +
 +    /**
 +     * Returns the key for the index summary entry at `index`.
 +     */
 +    public byte[] getIndexSummaryKey(int index)
 +    {
 +        return indexSummary.getKey(index);
 +    }
 +
 +    private static List<Pair<Integer,Integer>> getSampleIndexesForRanges(IndexSummary summary, Collection<Range<Token>> ranges)
 +    {
 +        // use the index to determine a minimal section for each range
 +        List<Pair<Integer,Integer>> positions = new ArrayList<>();
 +
 +        for (Range<Token> range : Range.normalize(ranges))
 +        {
 +            RowPosition leftPosition = range.left.maxKeyBound();
 +            RowPosition rightPosition = range.right.maxKeyBound();
 +
 +            int left = summary.binarySearch(leftPosition);
 +            if (left < 0)
 +                left = (left + 1) * -1;
 +            else
 +                // left range are start exclusive
 +                left = left + 1;
 +            if (left == summary.size())
 +                // left is past the end of the sampling
 +                continue;
 +
 +            int right = Range.isWrapAround(range.left, range.right)
 +                    ? summary.size() - 1
 +                    : summary.binarySearch(rightPosition);
 +            if (right < 0)
 +            {
 +                // range are end inclusive so we use the previous index from what binarySearch give us
 +                // since that will be the last index we will return
 +                right = (right + 1) * -1;
 +                if (right == 0)
 +                    // Means the first key is already stricly greater that the right bound
 +                    continue;
 +                right--;
 +            }
 +
 +            if (left > right)
 +                // empty range
 +                continue;
 +            positions.add(Pair.create(left, right));
 +        }
 +        return positions;
 +    }
 +
 +    public Iterable<DecoratedKey> getKeySamples(final Range<Token> range)
 +    {
 +        final List<Pair<Integer, Integer>> indexRanges = getSampleIndexesForRanges(indexSummary, Collections.singletonList(range));
 +
 +        if (indexRanges.isEmpty())
 +            return Collections.emptyList();
 +
 +        return new Iterable<DecoratedKey>()
 +        {
 +            public Iterator<DecoratedKey> iterator()
 +            {
 +                return new Iterator<DecoratedKey>()
 +                {
 +                    private Iterator<Pair<Integer, Integer>> rangeIter = indexRanges.iterator();
 +                    private Pair<Integer, Integer> current;
 +                    private int idx;
 +
 +                    public boolean hasNext()
 +                    {
 +                        if (current == null || idx > current.right)
 +                        {
 +                            if (rangeIter.hasNext())
 +                            {
 +                                current = rangeIter.next();
 +                                idx = current.left;
 +                                return true;
 +                            }
 +                            return false;
 +                        }
 +
 +                        return true;
 +                    }
 +
 +                    public DecoratedKey next()
 +                    {
 +                        byte[] bytes = indexSummary.getKey(idx++);
 +                        return partitioner.decorateKey(ByteBuffer.wrap(bytes));
 +                    }
 +
 +                    public void remove()
 +                    {
 +                        throw new UnsupportedOperationException();
 +                    }
 +                };
 +            }
 +        };
 +    }
 +
 +    /**
 +     * Determine the minimal set of sections that can be extracted from this SSTable to cover the given ranges.
 +     * @return A sorted list of (offset,end) pairs that cover the given ranges in the datafile for this SSTable.
 +     */
 +    public List<Pair<Long,Long>> getPositionsForRanges(Collection<Range<Token>> ranges)
 +    {
 +        // use the index to determine a minimal section for each range
 +        List<Pair<Long,Long>> positions = new ArrayList<>();
 +        for (Range<Token> range : Range.normalize(ranges))
 +        {
 +            assert !range.isWrapAround() || range.right.isMinimum();
 +            // truncate the range so it at most covers the sstable
 +            AbstractBounds<RowPosition> bounds = range.toRowBounds();
 +            RowPosition leftBound = bounds.left.compareTo(first) > 0 ? bounds.left : first.getToken().minKeyBound();
 +            RowPosition rightBound = bounds.right.isMinimum() ? last.getToken().maxKeyBound() : bounds.right;
 +
 +            if (leftBound.compareTo(last) > 0 || rightBound.compareTo(first) < 0)
 +                continue;
 +
 +            long left = getPosition(leftBound, Operator.GT).position;
 +            long right = (rightBound.compareTo(last) > 0)
 +                         ? (openReason == OpenReason.EARLY
 +                            // if opened early, we overlap with the old sstables by one key, so we know that the last
 +                            // (and further) key(s) will be streamed from these if necessary
 +                            ? getPosition(last.getToken().maxKeyBound(), Operator.GT).position
 +                            : uncompressedLength())
 +                         : getPosition(rightBound, Operator.GT).position;
 +
 +            if (left == right)
 +                // empty range
 +                continue;
 +
 +            assert left < right : String.format("Range=%s openReason=%s first=%s last=%s left=%d right=%d", range, openReason, first, last, left, right);
 +            positions.add(Pair.create(left, right));
 +        }
 +        return positions;
 +    }
 +
 +    public void invalidateCacheKey(DecoratedKey key)
 +    {
 +        KeyCacheKey cacheKey = new KeyCacheKey(metadata.cfId, descriptor, key.getKey());
 +        keyCache.remove(cacheKey);
 +    }
 +
 +    public void cacheKey(DecoratedKey key, RowIndexEntry info)
 +    {
 +        CachingOptions caching = metadata.getCaching();
 +
 +        if (!caching.keyCache.isEnabled()
 +                || keyCache == null
 +                || keyCache.getCapacity() == 0)
 +        {
 +            return;
 +        }
 +
 +        KeyCacheKey cacheKey = new KeyCacheKey(metadata.cfId, descriptor, key.getKey());
 +        logger.trace("Adding cache entry for {} -> {}", cacheKey, info);
 +        keyCache.put(cacheKey, info);
 +    }
 +
 +    public RowIndexEntry getCachedPosition(DecoratedKey key, boolean updateStats)
 +    {
 +        return getCachedPosition(new KeyCacheKey(metadata.cfId, descriptor, key.getKey()), updateStats);
 +    }
 +
 +    protected RowIndexEntry getCachedPosition(KeyCacheKey unifiedKey, boolean updateStats)
 +    {
 +        if (keyCache != null && keyCache.getCapacity() > 0) {
 +            if (updateStats)
 +            {
 +                RowIndexEntry cachedEntry = keyCache.get(unifiedKey);
 +                keyCacheRequest.incrementAndGet();
 +                if (cachedEntry != null)
++                {
 +                    keyCacheHit.incrementAndGet();
++                    bloomFilterTracker.addTruePositive();
++                }
 +                return cachedEntry;
 +            }
 +            else
 +            {
 +                return keyCache.getInternal(unifiedKey);
 +            }
 +        }
 +        return null;
 +    }
 +
 +    /**
 +     * Get position updating key cache and stats.
 +     * @see #getPosition(org.apache.cassandra.db.RowPosition, SSTableReader.Operator, boolean)
 +     */
 +    public RowIndexEntry getPosition(RowPosition key, Operator op)
 +    {
 +        return getPosition(key, op, true);
 +    }
 +
 +    /**
 +     * @param key The key to apply as the rhs to the given Operator. A 'fake' key is allowed to
 +     * allow key selection by token bounds but only if op != * EQ
 +     * @param op The Operator defining matching keys: the nearest key to the target matching the operator wins.
 +     * @param updateCacheAndStats true if updating stats and cache
 +     * @return The index entry corresponding to the key, or null if the key is not present
 +     */
 +    public abstract RowIndexEntry getPosition(RowPosition key, Operator op, boolean updateCacheAndStats);
 +
 +    //Corresponds to a name column
 +    public abstract OnDiskAtomIterator iterator(DecoratedKey key, SortedSet<CellName> columns);
 +    public abstract OnDiskAtomIterator iterator(FileDataInput file, DecoratedKey key, SortedSet<CellName> columns, RowIndexEntry indexEntry);
 +
 +    //Corresponds to a slice query
 +    public abstract OnDiskAtomIterator iterator(DecoratedKey key, ColumnSlice[] slices, boolean reverse);
 +    public abstract OnDiskAtomIterator iterator(FileDataInput file, DecoratedKey key, ColumnSlice[] slices, boolean reversed, RowIndexEntry indexEntry);
 +
 +    /**
 +     * Finds and returns the first key beyond a given token in this SSTable or null if no such key exists.
 +     */
 +    public DecoratedKey firstKeyBeyond(RowPosition token)
 +    {
 +        long sampledPosition = getIndexScanPosition(token);
 +        if (sampledPosition == -1)
 +            sampledPosition = 0;
 +
 +        Iterator<FileDataInput> segments = ifile.iterator(sampledPosition);
 +        while (segments.hasNext())
 +        {
 +            FileDataInput in = segments.next();
 +            try
 +            {
 +                while (!in.isEOF())
 +                {
 +                    ByteBuffer indexKey = ByteBufferUtil.readWithShortLength(in);
 +                    DecoratedKey indexDecoratedKey = partitioner.decorateKey(indexKey);
 +                    if (indexDecoratedKey.compareTo(token) > 0)
 +                        return indexDecoratedKey;
 +
 +                    RowIndexEntry.Serializer.skip(in);
 +                }
 +            }
 +            catch (IOException e)
 +            {
 +                markSuspect();
 +                throw new CorruptSSTableException(e, in.getPath());
 +            }
 +            finally
 +            {
 +                FileUtils.closeQuietly(in);
 +            }
 +        }
 +
 +        return null;
 +    }
 +
 +    /**
 +     * @return The length in bytes of the data for this SSTable. For
 +     * compressed files, this is not the same thing as the on disk size (see
 +     * onDiskLength())
 +     */
 +    public long uncompressedLength()
 +    {
 +        return dfile.length;
 +    }
 +
 +    /**
 +     * @return The length in bytes of the on disk size for this SSTable. For
 +     * compressed files, this is not the same thing as the data length (see
 +     * length())
 +     */
 +    public long onDiskLength()
 +    {
 +        return dfile.onDiskLength;
 +    }
 +
 +    public boolean acquireReference()
 +    {
 +        while (true)
 +        {
 +            int n = references.get();
 +            if (n <= 0)
 +                return false;
 +            if (references.compareAndSet(n, n + 1))
 +                return true;
 +        }
 +    }
 +
 +    @VisibleForTesting
 +    public int referenceCount()
 +    {
 +        return references.get();
 +    }
 +
 +    /**
 +     * Release reference to this SSTableReader.
 +     * If there is no one referring to this SSTable, and is marked as compacted,
 +     * all resources are cleaned up and files are deleted eventually.
 +     */
 +    public void releaseReference()
 +    {
 +        if (references.decrementAndGet() == 0)
 +            tidy(true);
 +        assert references.get() >= 0 : "Reference counter " +  references.get() + " for " + dfile.path;
 +    }
 +
 +    /**
 +     * Mark the sstable as obsolete, i.e., compacted into newer sstables.
 +     *
 +     * When calling this function, the caller must ensure that the SSTableReader is not referenced anywhere
 +     * except for threads holding a reference.
 +     *
 +     * @return true if the this is the first time the file was marked obsolete.  Calling this
 +     * multiple times is usually buggy (see exceptions in DataTracker.unmarkCompacting and removeOldSSTablesSize).
 +     */
 +    public boolean markObsolete()
 +    {
 +        if (logger.isDebugEnabled())
 +            logger.debug("Marking {} compacted", getFilename());
 +
 +        synchronized (replaceLock)
 +        {
 +            assert replacedBy == null : getFilename();
 +        }
 +        return !isCompacted.getAndSet(true);
 +    }
 +
 +    public boolean isMarkedCompacted()
 +    {
 +        return isCompacted.get();
 +    }
 +
 +    public void markSuspect()
 +    {
 +        if (logger.isDebugEnabled())
 +            logger.debug("Marking {} as a suspect for blacklisting.", getFilename());
 +
 +        isSuspect.getAndSet(true);
 +    }
 +
 +    public boolean isMarkedSuspect()
 +    {
 +        return isSuspect.get();
 +    }
 +
 +
 +    /**
 +     * I/O SSTableScanner
 +     * @return A Scanner for seeking over the rows of the SSTable.
 +     */
 +    public ISSTableScanner getScanner()
 +    {
 +        return getScanner((RateLimiter) null);
 +    }
 +
 +    public ISSTableScanner getScanner(RateLimiter limiter)
 +    {
 +        return getScanner(DataRange.allData(partitioner), limiter);
 +    }
 +
 +    /**
 +     *
 +     * @param dataRange filter to use when reading the columns
 +     * @return A Scanner for seeking over the rows of the SSTable.
 +     */
 +    public ISSTableScanner getScanner(DataRange dataRange)
 +    {
 +        return getScanner(dataRange, null);
 +    }
 +
 +    /**
 +     * Direct I/O SSTableScanner over a defined range of tokens.
 +     *
 +     * @param range the range of keys to cover
 +     * @return A Scanner for seeking over the rows of the SSTable.
 +     */
 +    public ISSTableScanner getScanner(Range<Token> range, RateLimiter limiter)
 +    {
 +        if (range == null)
 +            return getScanner(limiter);
 +        return getScanner(Collections.singletonList(range), limiter);
 +    }
 +
 +    /**
 +     * Direct I/O SSTableScanner over a defined collection of ranges of tokens.
 +     *
 +     * @param ranges the range of keys to cover
 +     * @return A Scanner for seeking over the rows of the SSTable.
 +     */
 +    public abstract ISSTableScanner getScanner(Collection<Range<Token>> ranges, RateLimiter limiter);
 +
 +    /**
 +     *
 +     * @param dataRange filter to use when reading the columns
 +     * @return A Scanner for seeking over the rows of the SSTable.
 +     */
 +    public abstract ISSTableScanner getScanner(DataRange dataRange, RateLimiter limiter);
 +
 +
 +
 +    public FileDataInput getFileDataInput(long position)
 +    {
 +        return dfile.getSegment(position);
 +    }
 +
 +    /**
 +     * Tests if the sstable contains data newer than the given age param (in localhost currentMilli time).
 +     * This works in conjunction with maxDataAge which is an upper bound on the create of data in this sstable.
 +     * @param age The age to compare the maxDataAre of this sstable. Measured in millisec since epoc on this host
 +     * @return True iff this sstable contains data that's newer than the given age parameter.
 +     */
 +    public boolean newSince(long age)
 +    {
 +        return maxDataAge > age;
 +    }
 +
 +    public void createLinks(String snapshotDirectoryPath)
 +    {
 +        for (Component component : components)
 +        {
 +            File sourceFile = new File(descriptor.filenameFor(component));
 +            File targetLink = new File(snapshotDirectoryPath, sourceFile.getName());
 +            FileUtils.createHardLink(sourceFile, targetLink);
 +        }
 +    }
 +
 +    public boolean isRepaired()
 +    {
 +        return sstableMetadata.repairedAt != ActiveRepairService.UNREPAIRED_SSTABLE;
 +    }
 +
 +    public SSTableReader getCurrentReplacement()
 +    {
 +        synchronized (replaceLock)
 +        {
 +            SSTableReader cur = this, next = replacedBy;
 +            while (next != null)
 +            {
 +                cur = next;
 +                next = next.replacedBy;
 +            }
 +            return cur;
 +        }
 +    }
 +
 +    /**
 +     * TODO: Move someplace reusable
 +     */
 +    public abstract static class Operator
 +    {
 +        public static final Operator EQ = new Equals();
 +        public static final Operator GE = new GreaterThanOrEqualTo();
 +        public static final Operator GT = new GreaterThan();
 +
 +        /**
 +         * @param comparison The result of a call to compare/compareTo, with the desired field on the rhs.
 +         * @return less than 0 if the operator cannot match forward, 0 if it matches, greater than 0 if it might match forward.
 +         */
 +        public abstract int apply(int comparison);
 +
 +        final static class Equals extends Operator
 +        {
 +            public int apply(int comparison) { return -comparison; }
 +        }
 +
 +        final static class GreaterThanOrEqualTo extends Operator
 +        {
 +            public int apply(int comparison) { return comparison >= 0 ? 0 : -comparison; }
 +        }
 +
 +        final static class GreaterThan extends Operator
 +        {
 +            public int apply(int comparison) { return comparison > 0 ? 0 : 1; }
 +        }
 +    }
 +
 +    public long getBloomFilterFalsePositiveCount()
 +    {
 +        return bloomFilterTracker.getFalsePositiveCount();
 +    }
 +
 +    public long getRecentBloomFilterFalsePositiveCount()
 +    {
 +        return bloomFilterTracker.getRecentFalsePositiveCount();
 +    }
 +
 +    public long getBloomFilterTruePositiveCount()
 +    {
 +        return bloomFilterTracker.getTruePositiveCount();
 +    }
 +
 +    public long getRecentBloomFilterTruePositiveCount()
 +    {
 +        return bloomFilterTracker.getRecentTruePositiveCount();
 +    }
 +
 +    public InstrumentingCache<KeyCacheKey, RowIndexEntry> getKeyCache()
 +    {
 +        return keyCache;
 +    }
 +
 +    public EstimatedHistogram getEstimatedRowSize()
 +    {
 +        return sstableMetadata.estimatedRowSize;
 +    }
 +
 +    public EstimatedHistogram getEstimatedColumnCount()
 +    {
 +        return sstableMetadata.estimatedColumnCount;
 +    }
 +
 +    public double getEstimatedDroppableTombstoneRatio(int gcBefore)
 +    {
 +        return sstableMetadata.getEstimatedDroppableTombstoneRatio(gcBefore);
 +    }
 +
 +    public double getDroppableTombstonesBefore(int gcBefore)
 +    {
 +        return sstableMetadata.getDroppableTombstonesBefore(gcBefore);
 +    }
 +
 +    public double getCompressionRatio()
 +    {
 +        return sstableMetadata.compressionRatio;
 +    }
 +
 +    public ReplayPosition getReplayPosition()
 +    {
 +        return sstableMetadata.replayPosition;
 +    }
 +
 +    public long getMinTimestamp()
 +    {
 +        return sstableMetadata.minTimestamp;
 +    }
 +
 +    public long getMaxTimestamp()
 +    {
 +        return sstableMetadata.maxTimestamp;
 +    }
 +
 +    public Set<Integer> getAncestors()
 +    {
 +        try
 +        {
 +            CompactionMetadata compactionMetadata = (CompactionMetadata) descriptor.getMetadataSerializer().deserialize(descriptor, MetadataType.COMPACTION);
 +            return compactionMetadata.ancestors;
 +        }
 +        catch (IOException e)
 +        {
 +            SSTableReader.logOpenException(descriptor, e);
 +            return Collections.emptySet();
 +        }
 +    }
 +
 +    public int getSSTableLevel()
 +    {
 +        return sstableMetadata.sstableLevel;
 +    }
 +
 +    /**
 +     * Reloads the sstable metadata from disk.
 +     *
 +     * Called after level is changed on sstable, for example if the sstable is dropped to L0
 +     *
 +     * Might be possible to remove in future versions
 +     *
 +     * @throws IOException
 +     */
 +    public void reloadSSTableMetadata() throws IOException
 +    {
 +        this.sstableMetadata = (StatsMetadata) descriptor.getMetadataSerializer().deserialize(descriptor, MetadataType.STATS);
 +    }
 +
 +    public StatsMetadata getSSTableMetadata()
 +    {
 +        return sstableMetadata;
 +    }
 +
 +    public RandomAccessReader openDataReader(RateLimiter limiter)
 +    {
 +        assert limiter != null;
 +        return compression
 +                ? CompressedThrottledReader.open(getFilename(), getCompressionMetadata(), limiter)
 +                : ThrottledReader.open(new File(getFilename()), limiter);
 +    }
 +
 +    public RandomAccessReader openDataReader()
 +    {
 +        return compression
 +                ? CompressedRandomAccessReader.open(getFilename(), getCompressionMetadata())
 +                : RandomAccessReader.open(new File(getFilename()));
 +    }
 +
 +    public RandomAccessReader openIndexReader()
 +    {
 +        return RandomAccessReader.open(new File(getIndexFilename()));
 +    }
 +
 +    /**
 +     * @param component component to get timestamp.
 +     * @return last modified time for given component. 0 if given component does not exist or IO error occurs.
 +     */
 +    public long getCreationTimeFor(Component component)
 +    {
 +        return new File(descriptor.filenameFor(component)).lastModified();
 +    }
 +
 +    /**
 +     * @return Number of key cache hit
 +     */
 +    public long getKeyCacheHit()
 +    {
 +        return keyCacheHit.get();
 +    }
 +
 +    /**
 +     * @return Number of key cache request
 +     */
 +    public long getKeyCacheRequest()
 +    {
 +        return keyCacheRequest.get();
 +    }
 +
 +    /**
 +     * @param sstables
 +     * @return true if all desired references were acquired.  Otherwise, it will unreference any partial acquisition, and return false.
 +     */
 +    public static boolean acquireReferences(Iterable<SSTableReader> sstables)
 +    {
 +        SSTableReader failed = null;
 +        for (SSTableReader sstable : sstables)
 +        {
 +            if (!sstable.acquireReference())
 +            {
 +                failed = sstable;
 +                break;
 +            }
 +        }
 +
 +        if (failed == null)
 +            return true;
 +
 +        for (SSTableReader sstable : sstables)
 +        {
 +            if (sstable == failed)
 +                break;
 +            sstable.releaseReference();
 +        }
 +        return false;
 +    }
 +
 +    public static void releaseReferences(Iterable<SSTableReader> sstables)
 +    {
 +        for (SSTableReader sstable : sstables)
 +        {
 +            sstable.releaseReference();
 +        }
 +    }
 +
 +    private void dropPageCache()
 +    {
 +        dropPageCache(dfile.path);
 +        dropPageCache(ifile.path);
 +    }
 +
 +    private void dropPageCache(String filePath)
 +    {
 +        RandomAccessFile file = null;
 +
 +        try
 +        {
 +            file = new RandomAccessFile(filePath, "r");
 +
 +            int fd = CLibrary.getfd(file.getFD());
 +
 +            if (fd > 0)
 +            {
 +                if (logger.isDebugEnabled())
 +                    logger.debug(String.format("Dropping page cache of file %s.", filePath));
 +
 +                CLibrary.trySkipCache(fd, 0, 0);
 +            }
 +        }
 +        catch (IOException e)
 +        {
 +            // we don't care if cache cleanup fails
 +        }
 +        finally
 +        {
 +            FileUtils.closeQuietly(file);
 +        }
 +    }
 +
 +    /**
 +     * Increment the total row read count and read rate for this SSTable.  This should not be incremented for range
 +     * slice queries, row cache hits, or non-query reads, like compaction.
 +     */
 +    public void incrementReadCount()
 +    {
 +        if (readMeter != null)
 +            readMeter.mark();
 +    }
 +
 +    public static class SizeComparator implements Comparator<SSTableReader>
 +    {
 +        public int compare(SSTableReader o1, SSTableReader o2)
 +        {
 +            return Longs.compare(o1.onDiskLength(), o2.onDiskLength());
 +        }
 +    }
 +
 +    public static abstract class Factory
 +    {
 +        public abstract SSTableReader open(final Descriptor descriptor,
 +                                           Set<Component> components,
 +                                           CFMetaData metadata,
 +                                           IPartitioner partitioner,
 +                                           Long maxDataAge,
 +                                           StatsMetadata sstableMetadata,
 +                                           OpenReason openReason);
 +
 +    }
 +}

http://git-wip-us.apache.org/repos/asf/cassandra/blob/c37e7bfb/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
----------------------------------------------------------------------
diff --cc test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
index 647a67b,51588f2..0a29255
--- a/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
+++ b/test/unit/org/apache/cassandra/io/sstable/SSTableReaderTest.java
@@@ -287,6 -263,37 +286,37 @@@ public class SSTableReaderTes
          // check if opening and querying works
          assertIndexQueryWorks(store);
      }
+     public void testGetPositionsKeyCacheStats() throws IOException, ExecutionException, InterruptedException
+     {
 -        Keyspace keyspace = Keyspace.open("Keyspace1");
++        Keyspace keyspace = Keyspace.open(KEYSPACE1);
+         ColumnFamilyStore store = keyspace.getColumnFamilyStore("Standard2");
+         CacheService.instance.keyCache.setCapacity(1000);
+ 
+         // insert data and compact to a single sstable
+         CompactionManager.instance.disableAutoCompaction();
+         for (int j = 0; j < 10; j++)
+         {
+             ByteBuffer key = ByteBufferUtil.bytes(String.valueOf(j));
+             Mutation rm = new Mutation("Keyspace1", key);
+             rm.add("Standard2", cellname("0"), ByteBufferUtil.EMPTY_BYTE_BUFFER, j);
+             rm.apply();
+         }
+         store.forceBlockingFlush();
+         CompactionManager.instance.performMaximal(store);
+ 
+         SSTableReader sstable = store.getSSTables().iterator().next();
+         sstable.getPosition(k(2), SSTableReader.Operator.EQ);
+         assertEquals(0, sstable.getKeyCacheHit());
+         assertEquals(1, sstable.getBloomFilterTruePositiveCount());
+         sstable.getPosition(k(2), SSTableReader.Operator.EQ);
+         assertEquals(1, sstable.getKeyCacheHit());
+         assertEquals(2, sstable.getBloomFilterTruePositiveCount());
+         sstable.getPosition(k(15), SSTableReader.Operator.EQ);
+         assertEquals(1, sstable.getKeyCacheHit());
+         assertEquals(2, sstable.getBloomFilterTruePositiveCount());
+ 
+     }
+ 
  
      @Test
      public void testOpeningSSTable() throws Exception