[jira] [Created] (CAMEL-21888) High CPU usage at startup due to Deque.size() iteration in SimpleLRUCache

["Nadina Florea (Jira)" <ji...@apache.org>]

Nadina Florea created CAMEL-21888:
-------------------------------------

             Summary: High CPU usage at startup due to Deque.size() iteration in SimpleLRUCache
                 Key: CAMEL-21888
                 URL: https://issues.apache.org/jira/browse/CAMEL-21888
             Project: Camel
          Issue Type: Bug
          Components: came-core
    Affects Versions: 4.7.0
            Reporter: Nadina Florea


Hello,

Starting with *Camel 4.7.0,* a change was introduced in *SimpleLRUCache,* where a *Deque* is now used to track *lastChanges.*

This change causes *high CPU usage at startup* when the cache is populated, as *Deque.size() iterates over all cache entries.*

This issue was observed only in production, after migrating to Camel 4.7.0, where the cache size is significantly large (1,200,000 entries at that time). Current stable version is Camel 4.6.0.

 

We are using {*}KafkaIdempotentRepository{*}, which relies on SimpleLRUCache. In our app, we expose a metric that contains the size of the cache at a certain point.
{code:java}
@Bean
@ConditionalOnBean(KafkaIdempotentRepository.class)
public MeterBinder cacheSize(final KafkaIdempotentRepository idempotentRepository) {
  return registry -> Gauge.builder("cacheSize",idempotentRepository::getCacheSize)
.register(registry);
}{code}
Would appreciate any insights on this issue.

 

 



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