Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/860#discussion_r128143493
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/record/SmartAllocationHelper.java
---
@@ -0,0 +1,156 @@
+/*
+ * 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.drill.exec.record;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.apache.drill.exec.vector.AllocationHelper;
+import org.apache.drill.exec.vector.ValueVector;
+import org.apache.drill.exec.vector.complex.AbstractMapVector;
+import org.apache.drill.exec.vector.complex.RepeatedMapVector;
+
+/**
+ * Prototype mechanism to allocate vectors based on expected
+ * data sizes. This version uses a name-based map of fields
+ * to sizes. Better to represent the batch structurally and
+ * simply iterate over the schema rather than doing a per-field
+ * lookup. But, the mechanisms needed to do the efficient solution
+ * don't exist yet.
+ */
+
+public class SmartAllocationHelper {
+
+ public static class AllocationHint {
+ public final int entryWidth;
+ public final int elementCount;
+
+ private AllocationHint(int width, int elements) {
+ entryWidth = width;
+ elementCount = elements;
+ }
+
+ @Override
+ public String toString() {
+ StringBuilder buf = new StringBuilder()
--- End diff --
Clever! Or I can leave it as it is:
* Use of string builder minimizes string copies
* Layout lends itself to adding/removing members (which happens a lot with
toString() methods)
* This is never used in production; only during debugging, so performance
is not a concern (which negates my first point, I suppose...)
Got rid of the flat (though at the cost of assigning to a string; which
someone didn't like in some previous Drill code review...)
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