svn commit: r1599218 - /lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java

[us...@apache.org]

Author: uschindler
Date: Mon Jun  2 13:35:42 2014
New Revision: 1599218

URL: http://svn.apache.org/r1599218
Log:
LUCENE-5722: Speed up MMapDirectory.seek() - first small patch for multi-mmap case

Modified:
    lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java

Modified: lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java
URL: http://svn.apache.org/viewvc/lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java?rev=1599218&r1=1599217&r2=1599218&view=diff
==============================================================================
--- lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java (original)
+++ lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java Mon Jun  2 13:35:42 2014
@@ -46,7 +46,7 @@ abstract class ByteBufferIndexInput exte
   private long length;
   private String sliceDescription;
 
-  private int curBufIndex;
+  private int curBufIndex = -1;
 
   private ByteBuffer curBuf; // redundant for speed: buffers[curBufIndex]
 
@@ -163,11 +163,15 @@ abstract class ByteBufferIndexInput exte
     // in case pos + offset overflows.
     final int bi = (int) (pos >> chunkSizePower);
     try {
-      final ByteBuffer b = buffers[bi];
-      b.position((int) (pos & chunkSizeMask));
-      // write values, on exception all is unchanged
-      this.curBufIndex = bi;
-      this.curBuf = b;
+      if (bi == curBufIndex) {
+        curBuf.position((int) (pos & chunkSizeMask));
+      } else {
+        final ByteBuffer b = buffers[bi];
+        b.position((int) (pos & chunkSizeMask));
+        // write values, on exception all is unchanged
+        this.curBufIndex = bi;
+        this.curBuf = b;
+      }
     } catch (ArrayIndexOutOfBoundsException aioobe) {
       throw new EOFException("seek past EOF: " + this);
     } catch (IllegalArgumentException iae) {
@@ -228,6 +232,7 @@ abstract class ByteBufferIndexInput exte
     clone.buffers = buildSlice(buffers, offset, length);
     clone.offset = (int) (offset & chunkSizeMask);
     clone.length = length;
+    clone.curBufIndex = -1;
 
     // register the new clone in our clone list to clean it up on closing:
     if (clones != null) {