diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IPartitionedInvertedIndex.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IPartitionedInvertedIndex.java
index 7db972c..89fd69d 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IPartitionedInvertedIndex.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/api/IPartitionedInvertedIndex.java
@@ -15,13 +15,17 @@
 
 package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api;
 
+import java.util.ArrayList;
+
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexOperationContext;
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.InvertedListPartitions;
 
 public interface IPartitionedInvertedIndex {
-    public void openInvertedListPartitionCursors(IInvertedIndexSearcher searcher, IIndexOperationContext ictx,
-            short numTokensLowerBound, short numTokensUpperBound, InvertedListPartitions invListPartitions)
-            throws HyracksDataException, IndexException;
+    public boolean openInvertedListPartitionCursors(IInvertedIndexSearcher searcher, IIndexOperationContext ictx,
+            short numTokensLowerBound, short numTokensUpperBound, InvertedListPartitions invListPartitions,
+            ArrayList<IInvertedListCursor> cursorsOrderedByTokens) throws HyracksDataException, IndexException;
+
+    public boolean isEmpty();
 }
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/dataflow/BinaryTokenizerOperatorNodePushable.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/dataflow/BinaryTokenizerOperatorNodePushable.java
index 0ad10a7..6f28f61 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/dataflow/BinaryTokenizerOperatorNodePushable.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/dataflow/BinaryTokenizerOperatorNodePushable.java
@@ -121,14 +121,13 @@
                 }
             }
         }
-
-        if (appender.getTupleCount() > 0) {
-            FrameUtils.flushFrame(writeBuffer, writer);
-        }
     }
 
     @Override
     public void close() throws HyracksDataException {
+        if (appender.getTupleCount() > 0) {
+            FrameUtils.flushFrame(writeBuffer, writer);
+        }
         writer.close();
     }
 
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/PartitionedInMemoryInvertedIndex.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/PartitionedInMemoryInvertedIndex.java
index 13e9b5c..7c3f4e4 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/PartitionedInMemoryInvertedIndex.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/inmemory/PartitionedInMemoryInvertedIndex.java
@@ -14,6 +14,7 @@
  */
 package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.inmemory;
 
+import java.util.ArrayList;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
@@ -30,6 +31,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOperation;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexSearcher;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListCursor;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IPartitionedInvertedIndex;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.InvertedListPartitions;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search.PartitionedTOccurrenceSearcher;
@@ -86,9 +88,9 @@
     }
 
     @Override
-    public void openInvertedListPartitionCursors(IInvertedIndexSearcher searcher, IIndexOperationContext ictx,
-            short numTokensLowerBound, short numTokensUpperBound, InvertedListPartitions invListPartitions)
-            throws HyracksDataException, IndexException {
+    public boolean openInvertedListPartitionCursors(IInvertedIndexSearcher searcher, IIndexOperationContext ictx,
+            short numTokensLowerBound, short numTokensUpperBound, InvertedListPartitions invListPartitions,
+            ArrayList<IInvertedListCursor> cursorsOrderedByTokens) throws HyracksDataException, IndexException {
         short minPartitionIndex;
         short maxPartitionIndex;
         partitionIndexLock.readLock().lock();
@@ -98,7 +100,7 @@
 
         if (minPartitionIndex == Short.MAX_VALUE && maxPartitionIndex == Short.MIN_VALUE) {
             // Index must be empty.
-            return;
+            return false;
         }
         short partitionStartIndex = minPartitionIndex;
         short partitionEndIndex = maxPartitionIndex;
@@ -108,7 +110,7 @@
         if (numTokensUpperBound >= 0) {
             partitionEndIndex = (short) Math.min(maxPartitionIndex, numTokensUpperBound);
         }
-        
+
         PartitionedTOccurrenceSearcher partSearcher = (PartitionedTOccurrenceSearcher) searcher;
         PartitionedInMemoryInvertedIndexOpContext ctx = (PartitionedInMemoryInvertedIndexOpContext) ictx;
         ctx.setOperation(IndexOperation.SEARCH);
@@ -127,5 +129,18 @@
             inMemListCursor.reset(searchKey);
             invListPartitions.addInvertedListCursor(inMemListCursor, i);
         }
+        return true;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        partitionIndexLock.readLock().lock();
+        if (minPartitionIndex == Short.MAX_VALUE && maxPartitionIndex == Short.MIN_VALUE) {
+            // Index must be empty.
+            partitionIndexLock.readLock().unlock();
+            return true;
+        }
+        partitionIndexLock.readLock().unlock();
+        return false;
     }
 }
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java
index ed8f600..f55a700 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/FixedSizeElementInvertedListCursor.java
@@ -46,6 +46,8 @@
     private final FixedSizeTupleReference tuple;
     private ICachedPage[] pages = new ICachedPage[10];
     private int[] elementIndexes = new int[10];
+    
+    private boolean pinned = false;
 
     public FixedSizeElementInvertedListCursor(IBufferCache bufferCache, int fileId, ITypeTraits[] invListFields) {
         this.bufferCache = bufferCache;
@@ -84,12 +86,16 @@
 
     @Override
     public void pinPages() throws HyracksDataException {
+        if (pinned) {
+            return;
+        }
         int pix = 0;
         for (int i = startPageId; i <= endPageId; i++) {
             pages[pix] = bufferCache.pin(BufferedFileHandle.getDiskPageId(fileId, i), false);
             pages[pix].acquireReadLatch();
             pix++;
         }
+        pinned = true;
     }
 
     @Override
@@ -99,6 +105,7 @@
             pages[i].releaseReadLatch();
             bufferCache.unpin(pages[i]);
         }
+        pinned = false;
     }
 
     private void positionCursor(int elementIx) {
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/PartitionedOnDiskInvertedIndex.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/PartitionedOnDiskInvertedIndex.java
index 5b2ec60..6e395e7 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/PartitionedOnDiskInvertedIndex.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/PartitionedOnDiskInvertedIndex.java
@@ -15,6 +15,8 @@
 
 package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk;
 
+import java.util.ArrayList;
+
 import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparatorFactory;
 import edu.uci.ics.hyracks.api.dataflow.value.ITypeTraits;
 import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
@@ -61,9 +63,9 @@
     }
 
     @Override
-    public void openInvertedListPartitionCursors(IInvertedIndexSearcher searcher, IIndexOperationContext ictx,
-            short numTokensLowerBound, short numTokensUpperBound, InvertedListPartitions invListPartitions)
-            throws HyracksDataException, IndexException {
+    public boolean openInvertedListPartitionCursors(IInvertedIndexSearcher searcher, IIndexOperationContext ictx,
+            short numTokensLowerBound, short numTokensUpperBound, InvertedListPartitions invListPartitions,
+            ArrayList<IInvertedListCursor> cursorsOrderedByTokens) throws HyracksDataException, IndexException {
         PartitionedTOccurrenceSearcher partSearcher = (PartitionedTOccurrenceSearcher) searcher;
         OnDiskInvertedIndexOpContext ctx = (OnDiskInvertedIndexOpContext) ictx;
         ITupleReference lowSearchKey = null;
@@ -86,6 +88,7 @@
         ctx.btreePred.setLowKey(lowSearchKey, true);
         ctx.btreePred.setHighKey(highSearchKey, true);
         ctx.btreeAccessor.search(ctx.btreeCursor, ctx.btreePred);
+        boolean tokenExists = false;
         try {
             while (ctx.btreeCursor.hasNext()) {
                 ctx.btreeCursor.next();
@@ -95,11 +98,19 @@
                         btreeTuple.getFieldStart(PARTITIONING_NUM_TOKENS_FIELD));
                 IInvertedListCursor invListCursor = partSearcher.getCachedInvertedListCursor();
                 resetInvertedListCursor(btreeTuple, invListCursor);
+                cursorsOrderedByTokens.add(invListCursor);
                 invListPartitions.addInvertedListCursor(invListCursor, numTokens);
+                tokenExists = true;
             }
         } finally {
             ctx.btreeCursor.close();
             ctx.btreeCursor.reset();
         }
+        return tokenExists;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return false;
     }
 }
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/PartitionedTOccurrenceSearcher.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/PartitionedTOccurrenceSearcher.java
index fb8b9b0..3ce1f48 100644
--- a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/PartitionedTOccurrenceSearcher.java
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/PartitionedTOccurrenceSearcher.java
@@ -43,6 +43,10 @@
     protected final ConcatenatingTupleReference fullLowSearchKey = new ConcatenatingTupleReference(2);
     protected final ConcatenatingTupleReference fullHighSearchKey = new ConcatenatingTupleReference(2);
 
+    // Inverted list cursors ordered by token. Used to read relevant inverted-list partitions of one token one after
+    // the other for better I/O performance (because the partitions of one inverted list are stored contiguously in a file).
+    // The above implies that we currently require holding all inverted list for a query in memory.
+    protected final ArrayList<IInvertedListCursor> cursorsOrderedByTokens = new ArrayList<IInvertedListCursor>();
     protected final InvertedListPartitions partitions = new InvertedListPartitions();
 
     public PartitionedTOccurrenceSearcher(IHyracksCommonContext ctx, IInvertedIndex invIndex) {
@@ -80,32 +84,69 @@
 
     public void search(OnDiskInvertedIndexSearchCursor resultCursor, InvertedIndexSearchPredicate searchPred,
             IIndexOperationContext ictx) throws HyracksDataException, IndexException {
+        IPartitionedInvertedIndex partInvIndex = (IPartitionedInvertedIndex) invIndex;
+        searchResult.reset();
+        if (partInvIndex.isEmpty()) {
+            return;
+        }
+        
         tokenizeQuery(searchPred);
         short numQueryTokens = (short) queryTokenAccessor.getTupleCount();
 
         IInvertedIndexSearchModifier searchModifier = searchPred.getSearchModifier();
         short numTokensLowerBound = searchModifier.getNumTokensLowerBound(numQueryTokens);
         short numTokensUpperBound = searchModifier.getNumTokensUpperBound(numQueryTokens);
-
-        IPartitionedInvertedIndex partInvIndex = (IPartitionedInvertedIndex) invIndex;
-        invListCursorCache.reset();
-        partitions.reset(numTokensLowerBound, numTokensUpperBound);
-        for (int i = 0; i < numQueryTokens; i++) {
-            searchKey.reset(queryTokenAccessor, i);
-            partInvIndex.openInvertedListPartitionCursors(this, ictx, numTokensLowerBound, numTokensUpperBound,
-                    partitions);
-        }
-
+        
         occurrenceThreshold = searchModifier.getOccurrenceThreshold(numQueryTokens);
         if (occurrenceThreshold <= 0) {
             throw new OccurrenceThresholdPanicException("Merge Threshold is <= 0. Failing Search.");
         }
-
-        // Process the partitions one-by-one.
+        
+        short maxCountPossible = numQueryTokens;
+        invListCursorCache.reset();
+        partitions.reset(numTokensLowerBound, numTokensUpperBound);
+        cursorsOrderedByTokens.clear();
+        for (int i = 0; i < numQueryTokens; i++) {
+            searchKey.reset(queryTokenAccessor, i);
+            if (!partInvIndex.openInvertedListPartitionCursors(this, ictx, numTokensLowerBound, numTokensUpperBound,
+                    partitions, cursorsOrderedByTokens)) {
+                maxCountPossible--;
+                // No results possible.
+                if (maxCountPossible < occurrenceThreshold) {                    
+                    return;
+                }
+            }
+        }
+        
         ArrayList<IInvertedListCursor>[] partitionCursors = partitions.getPartitions();
         short start = partitions.getMinValidPartitionIndex();
         short end = partitions.getMaxValidPartitionIndex();
-        searchResult.reset();
+        
+        // Typically, we only enter this case for disk-based inverted indexes. 
+        // TODO: This behavior could potentially lead to a deadlock if we cannot pin 
+        // all inverted lists in memory, and are forced to wait for a page to get evicted
+        // (other concurrent searchers may be in the same situation).
+        // We should detect such cases, then unpin all pages, and then keep retrying to pin until we succeed.
+        // This will require a different "tryPin()" mechanism in the BufferCache that will return false
+        // if we'd have to wait for a page to get evicted.
+        if (!cursorsOrderedByTokens.isEmpty()) {
+            for (int i = start; i <= end; i++) {
+                if (partitionCursors[i] == null) {
+                    continue;
+                }
+                // Prune partition because no element in it can satisfy the occurrence threshold.
+                if (partitionCursors[i].size() < occurrenceThreshold) {
+                    cursorsOrderedByTokens.removeAll(partitionCursors[i]);
+                }
+            }
+            // Pin all the cursors in the order of tokens.
+            int numCursors = cursorsOrderedByTokens.size();
+            for (int i = 0; i < numCursors; i++) {
+                cursorsOrderedByTokens.get(i).pinPages();
+            }
+        }
+        
+        // Process the partitions one-by-one.
         for (int i = start; i <= end; i++) {
             if (partitionCursors[i] == null) {
                 continue;
@@ -119,7 +160,7 @@
             invListMerger.reset();
             invListMerger.merge(partitionCursors[i], occurrenceThreshold, numPrefixLists, searchResult);
         }
-
+        
         resultCursor.open(null, searchPred);
     }