Performance degradation in evaluation of SpelExpression with access to Map [SPR-11388]

[spring-projects-issues]

Spenson Shih opened SPR-11388 and commented

Starting in spring 4.0, evaluating SpEL expressions with map access has suffered severe performance degradation.

The code snippet below is used to demonstrate:

Map<String, String> map = new HashMap<String, String>();
map.put("key", "value");
EvaluationContext context = new StandardEvaluationContext(map);

ExpressionParser spelExpressionParser = new SpelExpressionParser();
Expression expr = spelExpressionParser.parseExpression("#root['key']");

StopWatch s = new StopWatch();
s.start();
for (int i = 0; i < 10000; i++) {
	expr.getValue(context);
}
s.stop();
System.out.println(s.getTotalTimeMillis());

Using Spring 3.x, average time is 50ms. Upon upgrade to Spring 4.0, average time is 1000ms. Spring 4.0.1 is slightly better at 700ms.

---

Affects: 4.0 GA, 4.0.1

Referenced from: commits 7efd54e

[spring-projects-issues]

Juergen Hoeller commented

MapAccessTests.testGetValueFromRootMap is basically this one, for a starting point.