feat: adopt proper JMH based benchmark

Signed-off-by: Andreas Reichel <andreas@manticore-projects.com>

Author: manticore-projects

README.md

@@ -1,4 +1,4 @@
-# [JSqlParser 5.1 Website](https://jsqlparser.github.io/JSqlParser) <img src="src/site/sphinx/_images/logo-no-background.svg" alt="drawing" width="200" align="right"/>
+# [JSqlParser 5.2 Website](https://jsqlparser.github.io/JSqlParser) <img src="src/site/sphinx/_images/logo-no-background.svg" alt="drawing" width="200" align="right"/>
 
 [![CI](https://github.com/JSQLParser/JSqlParser/actions/workflows/ci.yml/badge.svg)](https://github.com/JSQLParser/JSqlParser/actions/workflows/ci.yml)
 [![Coverage Status](https://coveralls.io/repos/JSQLParser/JSqlParser/badge.svg?branch=master)](https://coveralls.io/r/JSQLParser/JSqlParser?branch=master)
@@ -69,6 +69,18 @@ JSQLParser-4.9 was the last JDK8 compatible version. JSQLParser-5.0 and later de
 
 Building JSQLParser-5.1 and newer with Gradle will depend on a JDK17 toolchain due to the used plugins.
 
+## Performan ce
+
+Unfortunately the released JSQLParser-5.2 shows a performance deterioration caused by commit [30cf5d7](https://github.com/JSQLParser/JSqlParser/commit/30cf5d7b930ae0a076f49deb5cc841d39e62b3dc) related to `FunctionAllColumns()`.
+This has been resolved in JSQLParser 5.3-SNAPSHOT and JMH benchmarks have been added to avoid such regressions in the future. Further all `LOOKAHEADS` have been revised one by one, and we have gained back a very good performance of the Parser.
+
+```text
+Benchmark                               (version)  Mode  Cnt    Score   Error  Units
+JSQLParserBenchmark.parseSQLStatements     latest  avgt   30   83.504 ± 1.557  ms/op <-- `FunctionAllColumns()` disabled
+JSQLParserBenchmark.parseSQLStatements        5.2  avgt   30  400.876 ± 8.291  ms/op
+JSQLParserBenchmark.parseSQLStatements        5.1  avgt   30   85.731 ± 1.288  ms/op
+```
+
 ## [Supported Grammar and Syntax](https://jsqlparser.github.io/JSqlParser/syntax.html)
 
 **JSqlParser** aims to support the SQL standard as well as all major RDBMS. Any missing syntax or features can be added on demand.

build.gradle

@@ -117,7 +117,8 @@ dependencies {
     testImplementation 'net.java.dev.javacc:javacc:+'
     javacc 'net.java.dev.javacc:javacc:+'
 
-
+    jmh 'org.openjdk.jmh:jmh-core:1.37'
+    jmh 'org.openjdk.jmh:jmh-generator-annprocess:1.37'
 }
 
 compileJavacc {
@@ -633,3 +634,11 @@ tasks.register('upload') {
 check {
     dependsOn jacocoTestCoverageVerification
 }
+
+jmh {
+    includes = ['.*JSQLParserBenchmark.*']
+    warmupIterations = 3
+    fork = 3
+    iterations = 10
+    timeOnIteration = '1s'
+}

src/site/sphinx/_static/jmh_results.txt

@@ -0,0 +1,20 @@
+-- Optimised LOOKAHEADS (replacing all syntactic lookahead by numeric lookaheads)
+Benchmark                               (version)  Mode  Cnt    Score    Error  Units
+JSQLParserBenchmark.parseSQLStatements     latest  avgt   15  264.132 ±  9.636  ms/op
+JSQLParserBenchmark.parseSQLStatements        5.2  avgt   15  415.744 ± 20.602  ms/op
+JSQLParserBenchmark.parseSQLStatements        5.1  avgt   15   89.387 ±  1.916  ms/op
+JSQLParserBenchmark.parseSQLStatements        5.0  avgt   15   68.810 ±  2.591  ms/op
+JSQLParserBenchmark.parseSQLStatements        4.9  avgt   15   60.515 ±  1.650  ms/op
+JSQLParserBenchmark.parseSQLStatements        4.8  avgt   15   60.002 ±  1.259  ms/op
+JSQLParserBenchmark.parseSQLStatements        4.7  avgt   15   73.291 ±  3.049  ms/op
+
+-- Optimised LOOKAHEADS (replacing huge numeric lookaheads with syntactic lookaheads again)
+Benchmark                               (version)  Mode  Cnt    Score    Error  Units
+JSQLParserBenchmark.parseSQLStatements     latest  avgt   15  249.408 ± 11.340  ms/op
+JSQLParserBenchmark.parseSQLStatements        5.2  avgt   15  388.453 ± 13.149  ms/op
+
+-- Disable `FunctionAllColumns()`
+Benchmark                               (version)  Mode  Cnt    Score   Error  Units
+JSQLParserBenchmark.parseSQLStatements     latest  avgt   30   83.504 ± 1.557  ms/op
+JSQLParserBenchmark.parseSQLStatements        5.2  avgt   30  400.876 ± 8.291  ms/op
+JSQLParserBenchmark.parseSQLStatements        5.1  avgt   30   85.731 ± 1.288  ms/op

src/site/sphinx/contribution.rst

@@ -77,7 +77,22 @@ The JSQLParser is generated by ``JavaCC`` based on the provided Grammar. The Gra
 
                   mvn verify
 
-   7) Create your `GitHub Pull Request <https://www.youtube.com/watch?v=nCKdihvneS0>`_
+   7) Verify the performance and avoid any deterioration
+
+      .. code-block:: shell
+          :caption: Gradle `check` Task
+
+              gradle jmh
+
+      .. code-block:: text
+                :caption: JMH performance results
+
+                    Benchmark                               (version)  Mode  Cnt    Score   Error  Units
+                    JSQLParserBenchmark.parseSQLStatements     latest  avgt   30   83.504 ± 1.557  ms/op
+                    JSQLParserBenchmark.parseSQLStatements        5.2  avgt   30  400.876 ± 8.291  ms/op
+                    JSQLParserBenchmark.parseSQLStatements        5.1  avgt   30   85.731 ± 1.288  ms/op
+
+   8) Create your `GitHub Pull Request <https://www.youtube.com/watch?v=nCKdihvneS0>`_
 
 Manage Reserved Keywords
 ------------------------------

src/test/java/net/sf/jsqlparser/benchmark/DynamicParserRunner.java

@@ -0,0 +1,31 @@
+package net.sf.jsqlparser.benchmark;
+
+import net.sf.jsqlparser.parser.CCJSqlParser;
+import net.sf.jsqlparser.statement.Statements;
+
+import java.lang.reflect.Method;
+import java.net.URLClassLoader;
+import java.util.concurrent.ExecutorService;
+import java.util.function.Consumer;
+
+public class DynamicParserRunner implements SqlParserRunner {
+    private final Method parseStatementsMethod;
+
+    public DynamicParserRunner(URLClassLoader loader) throws Exception {
+        Class<?> utilClass = loader.loadClass("net.sf.jsqlparser.parser.CCJSqlParserUtil");
+        Class<?> ccjClass = loader.loadClass("net.sf.jsqlparser.parser.CCJSqlParser");
+        Class<?> consumerClass = Class.forName("java.util.function.Consumer"); // interface OK
+        parseStatementsMethod = utilClass.getMethod(
+                "parseStatements",
+                String.class,
+                ExecutorService.class,
+                consumerClass);
+    }
+
+    @Override
+    public Statements parseStatements(String sql,
+            ExecutorService executorService,
+            Consumer<CCJSqlParser> consumer) throws Exception {
+        return (Statements) parseStatementsMethod.invoke(null, sql, executorService, null);
+    }
+}

src/test/java/net/sf/jsqlparser/benchmark/JSQLParserBenchmark.java

@@ -0,0 +1,80 @@
+package net.sf.jsqlparser.benchmark;
+
+import net.sf.jsqlparser.parser.CCJSqlParser;
+import net.sf.jsqlparser.statement.Statements;
+import org.openjdk.jmh.annotations.*;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.*;
+import java.util.concurrent.*;
+import java.util.function.Consumer;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Benchmark)
+public class JSQLParserBenchmark {
+
+    private String sqlContent;
+    private ExecutorService executorService;
+
+    SqlParserRunner runner;
+
+    // @Param({ "latest", "5.2", "5.1", "5.0", "4.9", "4.8", "4.7", "4.6", "4.5" })
+    @Param({"latest", "5.2", "5.1"})
+    public String version;
+
+    @Setup(Level.Trial)
+    public void setup() throws Exception {
+        if ("latest".equals(version)) {
+            runner = new LatestClasspathRunner(); // direct call, no reflection
+        } else {
+            Path jarPath = downloadJsqlparserJar(version);
+            URLClassLoader loader = new URLClassLoader(new URL[] {jarPath.toUri().toURL()}, null);
+            runner = new DynamicParserRunner(loader);
+        }
+
+        // Adjust path as necessary based on where source root is during test execution
+        Path path = Paths.get("src/test/resources/net/sf/jsqlparser/performance.sql");
+        sqlContent = Files.readString(path, StandardCharsets.UTF_8);
+        executorService = Executors.newSingleThreadExecutor();
+    }
+
+    private Path downloadJsqlparserJar(String version) throws IOException {
+        String jarUrl = String.format(
+                "https://repo1.maven.org/maven2/com/github/jsqlparser/jsqlparser/%s/jsqlparser-%s.jar",
+                version, version);
+
+        Path cacheDir = Paths.get("build/libs/downloaded-jars");
+        Files.createDirectories(cacheDir);
+        Path jarFile = cacheDir.resolve("jsqlparser-" + version + ".jar");
+
+        if (!Files.exists(jarFile)) {
+            System.out.println("Downloading " + version);
+            try (InputStream in = new URL(jarUrl).openStream()) {
+                Files.copy(in, jarFile);
+            }
+        }
+
+        return jarFile;
+    }
+
+    @Benchmark
+    public void parseSQLStatements() throws Exception {
+        final Statements statements = runner.parseStatements(
+                sqlContent,
+                executorService,
+                (Consumer<CCJSqlParser>) parser -> {
+                    // No-op consumer (or you can log/validate each parser if desired)
+                });
+        assert statements.size() == 4;
+    }
+
+    @TearDown(Level.Trial)
+    public void tearDown() {
+        executorService.shutdown();
+    }
+}

src/test/java/net/sf/jsqlparser/benchmark/LatestClasspathRunner.java

@@ -0,0 +1,19 @@
+package net.sf.jsqlparser.benchmark;
+
+import net.sf.jsqlparser.parser.CCJSqlParser;
+import net.sf.jsqlparser.statement.Statements;
+
+import java.util.concurrent.ExecutorService;
+import java.util.function.Consumer;
+
+public class LatestClasspathRunner implements SqlParserRunner {
+
+    @Override
+    public Statements parseStatements(String sql,
+            ExecutorService executorService,
+            Consumer<CCJSqlParser> consumer) throws Exception {
+        return net.sf.jsqlparser.parser.CCJSqlParserUtil.parseStatements(sql, executorService,
+                consumer);
+    }
+}
+

src/test/java/net/sf/jsqlparser/benchmark/SqlParserRunner.java

@@ -0,0 +1,12 @@
+package net.sf.jsqlparser.benchmark;
+
+import net.sf.jsqlparser.parser.CCJSqlParser;
+import net.sf.jsqlparser.statement.Statements;
+
+import java.util.concurrent.ExecutorService;
+import java.util.function.Consumer;
+
+public interface SqlParserRunner {
+    Statements parseStatements(String sql, ExecutorService executorService,
+            Consumer<CCJSqlParser> consumer) throws Exception;
+}