[GitHub] [calcite] zabetak commented on a change in pull request #1080: [CALCITE-2887] Improve performance of RelLiteral#toJavaString

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zabetak commented on a change in pull request #1080: [CALCITE-2887] Improve performance of RelLiteral#toJavaString
URL: https://github.com/apache/calcite/pull/1080#discussion_r262063337
 
 

 ##########
 File path: ubenchmark/src/main/java/org/apache/calcite/benchmarks/StringConstructBenchmark.java
 ##########
 @@ -0,0 +1,133 @@
+/*
+ * 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.calcite.benchmarks;
+
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Threads;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.io.Writer;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * A benchmark of the most common patterns that are used to construct gradually String objects.
+ *
+ * The benchmark emphasizes on the build patterns that appear in the Calcite project.
+ */
+@Fork(value = 1, jvmArgsPrepend = "-Xmx2048m")
+@Measurement(iterations = 10, time = 100, timeUnit = TimeUnit.MILLISECONDS)
+@Warmup(iterations = 10, time = 100, timeUnit = TimeUnit.MILLISECONDS)
+@Threads(1)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@BenchmarkMode(Mode.Throughput)
+public class StringConstructBenchmark {
+
+  /**
+   * A state holding a Writer object which is initialized only once at the beginning of the
+   * benchmark.
+   */
+  @State(Scope.Thread)
+  public static class WriterState {
+    public Writer writer;
+
+    @Setup(Level.Trial)
+    public void setup() {
+      this.writer = new StringWriter();
+    }
+  }
+
+  /**
+   * A state holding an Appendable object which is initialized once at the beginning of every
+   * iteration.
+   */
+  @State(Scope.Thread)
+  public static class AppenderState {
+    /**
+     * The type of the appender to be initialised.
+     */
+    @Param({"StringBuilder", "StringWriter", "PrintWriter"})
+    public String appenderType;
+
+    public Appendable appender;
+
+    @Setup(Level.Iteration)
+    public void setup() {
+      if (appenderType.equals("StringBuilder")) {
+        this.appender = new StringBuilder();
+      }
+      if (appenderType.equals("StringWriter")) {
+        this.appender = new StringWriter();
+      }
+      if (appenderType.equals("PrintWriter")) {
+        this.appender = new PrintWriter(new StringWriter());
+      }
+      throw new IllegalStateException("No correct appender type is specified.");
+    }
+  }
+
+  @Benchmark
+  public StringBuilder initStringBuilder() {
+    return new StringBuilder();
+  }
+
+  @Benchmark
+  public StringWriter initStringWriter() {
+    return new StringWriter();
+  }
+
+  @Benchmark
+  public PrintWriter initPrintWriter(WriterState writerState) {
+    return new PrintWriter(writerState.writer);
+  }
+
+
+  @Benchmark
+  public void appendString(Blackhole bh, AppenderState appenderState) throws IOException {
+    bh.consume(appenderState.appender.append("A small string"));
 
 Review comment:
   @vlsi : I changed a bit the `appendString` benchmark to include `@Param int maxAppends` so now it also includes the time to instantiate the Appendable. This is a more realistic representation of what is happening in `RexLiteral#toJavaString`.

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