perf: Add microbenchmark for hash expressions

spark/src/test/scala/org/apache/spark/sql/benchmark/CometHashExpressionBenchmark.scala

@@ -0,0 +1,74 @@
+/*
+ * 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.spark.sql.benchmark
+
+case class HashExprConfig(
+    name: String,
+    query: String,
+    extraCometConfigs: Map[String, String] = Map.empty)
+
+/**
+ * Comprehensive benchmark for Comet hash expressions. To run this benchmark:
+ * {{{
+ *   SPARK_GENERATE_BENCHMARK_FILES=1 make benchmark-org.apache.spark.sql.benchmark.CometHashExpressionBenchmark
+ * }}}
+ * Results will be written to "spark/benchmarks/CometHashExpressionBenchmark-**results.txt".
+ */
+object CometHashExpressionBenchmark extends CometBenchmarkBase {
+
+  private val hashExpressions = List(
+    HashExprConfig("xxhash64_single", "SELECT xxhash64(c_str) FROM parquetV1Table"),
+    HashExprConfig("xxhash64_multi", "SELECT xxhash64(c_str, c_int, c_long) FROM parquetV1Table"),
+    HashExprConfig("murmur3_hash_single", "SELECT hash(c_str) FROM parquetV1Table"),
+    HashExprConfig("murmur3_hash_multi", "SELECT hash(c_str, c_int, c_long) FROM parquetV1Table"),
+    HashExprConfig("sha1", "SELECT sha1(c_str) FROM parquetV1Table"),
+    HashExprConfig("sha2_224", "SELECT sha2(c_str, 224) FROM parquetV1Table"),
+    HashExprConfig("sha2_256", "SELECT sha2(c_str, 256) FROM parquetV1Table"),
+    HashExprConfig("sha2_384", "SELECT sha2(c_str, 384) FROM parquetV1Table"),
+    HashExprConfig("sha2_512", "SELECT sha2(c_str, 512) FROM parquetV1Table"))
+
+  override def runCometBenchmark(mainArgs: Array[String]): Unit = {
+    val values = 1024 * 1024
+
+    runBenchmarkWithTable("Hash expression benchmarks", values) { v =>
+      withTempPath { dir =>
+        withTempTable("parquetV1Table") {
+          // Data distribution: 1% NULL per column
+          // - c_str: unique strings "string_0" through "string_N"
+          // - c_int: integers 0-999,999 (cycling)
+          // - c_long: large values 0 to ~1 billion
+          prepareTable(
+            dir,
+            spark.sql(s"""
+              SELECT
+                CASE WHEN value % 100 = 0 THEN NULL ELSE CONCAT('string_', CAST(value AS STRING)) END AS c_str,
+                CASE WHEN value % 100 = 1 THEN NULL ELSE CAST(value % 1000000 AS INT) END AS c_int,
+                CASE WHEN value % 100 = 2 THEN NULL ELSE CAST(value * 1000 AS LONG) END AS c_long
+              FROM $tbl
+            """))
+
+          hashExpressions.foreach { config =>
+            runExpressionBenchmark(config.name, v, config.query, config.extraCometConfigs)
+          }
+        }
+      }
+    }
+  }
+}