[GitHub] [druid] gianm commented on a change in pull request #11201: Add "stringEncoding" parameter to DataSketches HLL.

[GitBox <gi...@apache.org>]

gianm commented on a change in pull request #11201:
URL: https://github.com/apache/druid/pull/11201#discussion_r637966467



##########
File path: extensions-core/datasketches/src/main/java/org/apache/druid/query/aggregation/datasketches/hll/vector/ObjectHllSketchBuildVectorProcessor.java
##########
@@ -0,0 +1,86 @@
+/*
+ * 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.druid.query.aggregation.datasketches.hll.vector;
+
+import org.apache.datasketches.hll.HllSketch;
+import org.apache.druid.java.util.common.StringEncoding;
+import org.apache.druid.query.aggregation.datasketches.hll.HllSketchBuildBufferAggregatorHelper;
+import org.apache.druid.query.aggregation.datasketches.hll.HllSketchBuildUtil;
+import org.apache.druid.segment.vector.VectorObjectSelector;
+
+import javax.annotation.Nullable;
+import java.nio.ByteBuffer;
+
+/**
+ * Processor that handles cases where string columns are presented as object selectors instead of dimension selectors.
+ */
+public class ObjectHllSketchBuildVectorProcessor implements HllSketchBuildVectorProcessor
+{
+  private final HllSketchBuildBufferAggregatorHelper helper;
+  private final StringEncoding stringEncoding;
+  private final VectorObjectSelector selector;
+
+  public ObjectHllSketchBuildVectorProcessor(
+      final HllSketchBuildBufferAggregatorHelper helper,
+      final StringEncoding stringEncoding,
+      final VectorObjectSelector selector
+  )
+  {
+    this.helper = helper;
+    this.stringEncoding = stringEncoding;
+    this.selector = selector;
+  }
+
+  @Override
+  public void aggregate(ByteBuffer buf, int position, int startRow, int endRow)
+  {
+    final Object[] vector = selector.getObjectVector();
+    final HllSketch sketch = helper.getSketchAtPosition(buf, position);
+
+    for (int i = startRow; i < endRow; i++) {
+      if (vector[i] != null) {
+        HllSketchBuildUtil.updateSketch(
+            sketch,
+            stringEncoding,
+            vector[i]
+        );
+      }
+    }
+  }
+
+  @Override
+  public void aggregate(ByteBuffer buf, int numRows, int[] positions, @Nullable int[] rows, int positionOffset)
+  {
+    final Object[] vector = selector.getObjectVector();

Review comment:
       Ah, good catch, I'll figure out why the tests didn't catch it. I think we might need to use a filtered aggregator.




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org



---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For additional commands, e-mail: commits-help@druid.apache.org