Add a simple benchmark for statement parser

Also fixes the pom to run the annotation processor so that
mvn -Pbenchmark actually is able to run benchmarks.

Author: toddlipcon

google-cloud-spanner/pom.xml

@@ -517,6 +517,19 @@
               </execution>
             </executions>
           </plugin>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-compiler-plugin</artifactId>
+            <configuration>
+              <annotationProcessorPaths>
+                <path>
+                  <groupId>org.openjdk.jmh</groupId>
+                  <artifactId>jmh-generator-annprocess</artifactId>
+                  <version>1.37</version>
+                </path>
+              </annotationProcessorPaths>
+            </configuration>
+          </plugin>
         </plugins>
       </build>
     </profile>

google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/StatementParserBenchmark.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed 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 com.google.cloud.spanner.connection;
+
+import com.google.cloud.spanner.Dialect;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Warmup;
+
+@Fork(value = 1, warmups = 0)
+@Warmup(iterations = 1, time = 5)
+@Measurement(iterations = 5, time = 5)
+public class StatementParserBenchmark {
+  private static final Dialect dialect = Dialect.POSTGRESQL;
+  private static final AbstractStatementParser parser =
+      AbstractStatementParser.getInstance(dialect);
+
+  private static String longQueryText = generateLongQuery(100 * 1024); // 100kb
+
+  /** Generates a long SQL-looking string. */
+  private static String generateLongQuery(int length) {
+    StringBuilder sb = new StringBuilder(length + 50);
+    sb.append("SELECT * FROM foo WHERE 1");
+    while (sb.length() < length) {
+      sb.append(" OR abcdefghijklmnopqrstuvwxyz");
+    }
+    return sb.toString();
+  }
+
+  @Benchmark
+  public boolean isQueryTest() {
+    return parser.isQuery("CREATE TABLE FOO (ID INT64, NAME STRING(100)) PRIMARY KEY (ID)");
+  }
+
+  @Benchmark
+  public boolean longQueryTest() {
+    return parser.isQuery(longQueryText);
+  }
+}