Add micro benchmark by JMH

benchmarks/README.md

@@ -0,0 +1,19 @@
+# OpenSearch SQL/PPL Microbenchmark Suite
+
+This directory contains the microbenchmark suite of OpenSearch SQL/PPL. It relies on [JMH](http://openjdk.java.net/projects/code-tools/jmh/).
+
+## Purpose
+
+Microbenchmarks are intended to spot performance regressions in performance-critical components.
+
+The microbenchmark suite is also handy for ad-hoc microbenchmarks but please remove them again before merging your PR.
+
+## Getting Started
+
+Just run `./gradlew :benchmarks:jmh` from the project root directory or run specific benchmark via your IDE. It will build all microbenchmarks, execute them and print the result.
+
+## Adding Microbenchmarks
+
+Before adding a new microbenchmark, make yourself familiar with the JMH API. You can check our existing microbenchmarks and also the [JMH samples](http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/).
+
+In contrast to tests, the actual name of the benchmark class is not relevant to JMH. However, stick to the naming convention and end the class name of a benchmark with `Benchmark`. To have JMH execute a benchmark, annotate the respective methods with `@Benchmark`.

benchmarks/build.gradle

@@ -0,0 +1,23 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+plugins {
+    id 'java-library'
+    id "me.champeau.jmh" version "0.6.8"
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation project(':core')
+
+    // Dependencies required by JMH micro benchmark
+    api group: 'org.openjdk.jmh', name: 'jmh-core', version: '1.36'
+    annotationProcessor group: 'org.openjdk.jmh', name: 'jmh-generator-annprocess', version: '1.36'
+}
+
+compileJava.options.compilerArgs.addAll(["-processor", "org.openjdk.jmh.generators.BenchmarkProcessor"])

benchmarks/src/jmh/java/org/opensearch/sql/expression/operator/predicate/ComparisonOperatorBenchmark.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.expression.operator.predicate;
+
+import static org.opensearch.sql.data.model.ExprValueUtils.fromObjectValue;
+import static org.opensearch.sql.data.model.ExprValueUtils.integerValue;
+import static org.opensearch.sql.data.model.ExprValueUtils.stringValue;
+import static org.opensearch.sql.data.type.ExprCoreType.DATE;
+import static org.opensearch.sql.expression.DSL.literal;
+
+import com.google.common.collect.ImmutableMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Function;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+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.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.opensearch.sql.data.model.ExprValue;
+import org.opensearch.sql.expression.DSL;
+import org.opensearch.sql.expression.Expression;
+import org.opensearch.sql.expression.FunctionExpression;
+
+@Warmup(iterations = 1)
+@Measurement(iterations = 3)
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Thread)
+@Fork(value = 1)
+public class ComparisonOperatorBenchmark {
+
+  @Param(value = { "int", "string", "date" })
+  private String testDataType;
+
+  private final Map<String, ExprValue> params =
+      ImmutableMap.<String, ExprValue>builder()
+          .put("int", integerValue(1))
+          .put("string", stringValue("hello"))
+          .put("date", fromObjectValue("2022-01-12", DATE))
+          .build();
+
+  @Benchmark
+  public void testEqualOperator() {
+    run(DSL::equal);
+  }
+
+  @Benchmark
+  public void testLessOperator() {
+    run(DSL::less);
+  }
+
+  @Benchmark
+  public void testGreaterOperator() {
+    run(DSL::greater);
+  }
+
+  private void run(Function<Expression[], FunctionExpression> dsl) {
+    ExprValue param = params.get(testDataType);
+    FunctionExpression func = dsl.apply(new Expression[] {
+        literal(param), literal(param)
+    });
+    func.valueOf();
+  }
+}

settings.gradle

@@ -18,3 +18,4 @@ include 'doctest'
 include 'legacy'
 include 'sql'
 include 'prometheus'
+include 'benchmarks'