Improve performance of assertion in StompSubProtocolHandler [SPR-14624]

[spring-projects-issues]

Christoph Dreis opened SPR-14624 and commented

Hey,

I just noticed a rather costly assertion in the websocket layer - more explicitly in StompSubProtocolHandler.convertConnectAcktoStompConnected().

As the framework is now using Java 8 features, I wanted to add methods in Assert that can make use of suppliers. But you already did that ;-)

So I just used the new methods in an isolated test for a benchmark and the results show a crazy factor of 4300. I might be tricked by dead code elimination or some other compiler voodoo, because I don't trust those results.

@BenchmarkMode(Mode.Throughput)
@State(Scope.Thread)
public class MyBenchmark {

    @State(Scope.Thread)
    public static class TestState {
        public String testObject = "a";
        public StompHeaderAccessor headerAccessor;

        public TestState() {
            MultiValueMap<String, String> extHeaders = new LinkedMultiValueMap<>();
            extHeaders.add(StompHeaderAccessor.STOMP_LOGIN_HEADER, "joe");
            extHeaders.add(StompHeaderAccessor.STOMP_PASSCODE_HEADER, "joe123");
            headerAccessor = StompHeaderAccessor.create(StompCommand.CONNECT, extHeaders);
        }

    }

    @Benchmark
    public void testAssertNormal(TestState testState) {
        for (int i = 0; i < 1000; i++) {
            Assert.notNull(testState.testObject, "Original STOMP CONNECT not found in " + testState.headerAccessor);
        }
    }

    @Benchmark
    public void testAssertSupplier(TestState testState) {
        for (int i = 0; i < 1000; i++) {
            Assert.notNull(testState.testObject, () -> "Original STOMP CONNECT not found in " + testState.headerAccessor);
        }
    }

}

Benchmark	Mode	Cnt	Score	Error	Units
MyBenchmark.testAssertNormal	thrpt	30	966,149	12,945	ops/s
MyBenchmark.testAssertSupplier	thrpt	30	4194886,453	72553,850	ops/s

Nevertheless, I changed the code to use the supplier methods in the attached PR.

Unfortunately, this will be only available in 5.x so I would appreciate a solution for 4.x that avoids the apparently rather costly assertion/string-concatenation of StompHeaderAccessor instances.

Best,
Christoph

---

Affects: 4.2.7, 4.3.2

Reference URL: #1138

Issue Links:

• Fix assertions in StompHeaderAccessor [SPR-14625] #19192 Fix assertions in StompHeaderAccessor
• Improve performance of StompCommand.getMessageType() [SPR-14636] #19203 Improve performance of StompCommand.getMessageType()
• Improve performance of StompEncoder.encode() [SPR-14747] #19313 Improve performance of StompEncoder.encode()

Referenced from: commits 0735e9b, 3811a59, 56b197b

Backported to: 4.2.8

[spring-projects-issues]

Juergen Hoeller commented

Good catch! It's also throwing the wrong exception type, actually, since this is really a state assertion, not an argument assertion. For the sake of consistency, I've turned this into a traditional if clause throwing an IllegalStateException.

Additionally, StompSubProtocolHandler contained several inefficient logging statements with String concatenation. I've revised all of those to be guarded accordingly and will backport those to 4.3.3 and 4.2.8 as well.