Merge pull request #1 from sirensolutions/issue-3023

do not allocate a new offset buffer if the slice starts at 0 since th…
sirensolutions · Feb 18, 2020 · 5b13305 · 5b13305
2 parents 225ebea + a2f4572
commit 5b13305
Showing 1 changed file with 10 additions and 4 deletions.
diff --git a/java/vector/src/main/java/org/apache/arrow/vector/BaseVariableWidthVector.java b/java/vector/src/main/java/org/apache/arrow/vector/BaseVariableWidthVector.java
@@ -717,10 +717,16 @@ private void splitAndTransferOffsetBuffer(int startIndex, int length, BaseVariab
     final int start = offsetBuffer.getInt(startIndex * OFFSET_WIDTH);
     final int end = offsetBuffer.getInt((startIndex + length) * OFFSET_WIDTH);
     final int dataLength = end - start;
-    target.allocateOffsetBuffer((length + 1) * OFFSET_WIDTH);
-    for (int i = 0; i < length + 1; i++) {
-      final int relativeSourceOffset = offsetBuffer.getInt((startIndex + i) * OFFSET_WIDTH) - start;
-      target.offsetBuffer.setInt(i * OFFSET_WIDTH, relativeSourceOffset);
+
+    if (startIndex == 0) {
+      target.offsetBuffer = offsetBuffer.slice(0, (1 + length) * OFFSET_WIDTH);
+      target.offsetBuffer.getReferenceManager().retain();
+    } else {
+      target.allocateOffsetBuffer((length + 1) * OFFSET_WIDTH);
+      for (int i = 0; i < length + 1; i++) {
+        final int relativeSourceOffset = offsetBuffer.getInt((startIndex + i) * OFFSET_WIDTH) - start;
+        target.offsetBuffer.setInt(i * OFFSET_WIDTH, relativeSourceOffset);
+      }
     }
     final ArrowBuf slicedBuffer = valueBuffer.slice(start, dataLength);
     target.valueBuffer = transferBuffer(slicedBuffer, target.allocator);