First invocation of Event.parse(tsv) takes much longer than subsequent invocations

[arthur78]

Hi guys,

I'm using 3.2.1 version of SDK in a Java application. When I run a unit test doing several parse calls in a row, I see that the very first call is taking significantly more time than the rest.

Here's a function called by the unit test several times in a loop:

protected static String tsv2json(String sourceEventInTsv) {
    long startTime = System.currentTimeMillis();
    Validated<ParsingError, Event> validatedEvent = Event.parse(sourceEventInTsv);
    long endTime = System.currentTimeMillis();
    long executionTime = endTime - startTime;
    System.out.println("Execution time in milliseconds: " + executionTime);
    if (validatedEvent.isValid()) {
        Event event = validatedEvent.toOption().get();
        return event.toJson(true).noSpaces(); 
    }
    throw new InvalidSnowplowEvent(String.format("Invalid Snowplow event in TSV [%s]: %s",
            validatedEvent.toString(), sourceEventInTsv));
}

The test is run on a new M3 Mac, openJDK@21, for example:

Execution time in milliseconds: 173
Execution time in milliseconds: 1
Execution time in milliseconds: 2
Execution time in milliseconds: 1
Execution time in milliseconds: 2
Execution time in milliseconds: 2
Execution time in milliseconds: 1
Execution time in milliseconds: 1
Execution time in milliseconds: 1

The TSV fixture strings are about 4000-6000 chars length.

Could you please take a look and let me know if there's something wrong here. Thank you.

[arthur78]

On the lambda with 768 MB allocated memory, the first conversion takes ~4 seconds.