All geek questions in one place

Ehcache loses objects

I use Ehcache to cache objects that load very expensive in my application. At startup, I cache all the necessary objects, and they are updated once a day by a separate process.

However, it seems that soon after adding objects to the cache, they disappear. Nothing is reported as evicted, but for some reason, the objects are not stored in the cache. When I run ObjectLoader.loadCache (), this is the result that I get:

2012-09-01 17:25:37,121 [main] DEBUG ObjectLoader.getObject():65 - ************************************ 2012-09-01 17:25:37,121 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 0 2012-09-01 17:25:37,121 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 501 2012-09-01 17:26:17,271 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1 2012-09-01 17:26:17,271 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0 2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 501 2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():65 - ************************************ 2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1 2012-09-01 17:26:17,274 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 518 2012-09-01 17:26:35,894 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1 2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0 2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 518 2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():65 - ************************************ 2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1 2012-09-01 17:26:35,895 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 516 2012-09-01 17:27:31,997 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1 2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0 2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 516 2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():65 - ************************************ 2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1 2012-09-01 17:27:31,998 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 515 2012-09-01 17:28:20,343 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1 2012-09-01 17:28:20,343 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0 2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 515 2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():65 - ************************************ 2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1 2012-09-01 17:28:20,344 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 525 2012-09-01 17:29:05,616 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1 2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0 2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 525 2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():65 - ************************************ 2012-09-01 17:29:05,617 [main] DEBUG ObjectLoader.getObject():66 - Number of objects in cache: 1 2012-09-01 17:29:05,618 [main] DEBUG ObjectLoader.getObject():72 - Object not in cache | 512 2012-09-01 17:29:38,790 [main] DEBUG ObjectLoader.getObject():80 - Number of objects in cache: 1 2012-09-01 17:29:38,790 [main] DEBUG ObjectLoader.getObject():81 - Number of objects evicted from cache: 0 2012-09-01 17:29:38,790 [main] DEBUG ObjectLoader.getObject():83 - Object key found: 512

Am I having ehcache configured incorrectly or am I having an error in my code? Any help would be greatly appreciated. Thank you

I am using spring 3.1.0, ehcache-spring -nnotations 1.1.2 and ehcache 2.4.2

ObjectCacheFacade.java

 @Component() public class ObjectCacheFacade { private static final String CACHE_KEY = "myObjectCache"; @Resource private CacheManager cacheManager; private Cache cache; public ObjectCacheFacade() { cacheManager = CacheManager.getInstance(); this.cache = cacheManager.getCache(CACHE_KEY); } public Object getObjectFromCache(String objectId) { Object result = null; Element element = cache.get(objectId); if (element != null && element.getValue() != null) { result = element.getObjectValue(); } return result; } public void putObjectIntoCache(String objectId, Object object) { Element element = new Element(objectId, object); cache.put(element); } public int getSize() { return cache.getSize(); } public void removeObjectFromCache(String objectId) { cache.remove(objectId); } public void flushCache() { cache.removeAll(); } public Cache getCache() { return cache; } }

ObjectLoader.java

 @Service public class ObjectLoader { private static final Logger log = Logger.getLogger(ObjectLoader.class); @Resource protected ObjectDao objectDao; @Resource protected ObjectCacheFacade objectCache; public void loadCache() { List<String> objectIds = objectDao.getObjectIds(); for (String objectId : objectIds) { loadObject(objectId); } } public Object getObject(String objectId) { log.debug("************************************"); log.debug("Number of objects in cache: " + objectCache.getSize()); Object object = objectCache.getObjectFromCache(objectId); if (object == null) { log.debug("Object not in cache | " + objectId); object = objectDao.getObject(objectId); if (object != null) { objectCache.putObjectIntoCache(objectId, object); log.debug("Number of objects in cache: " + objectCache.getSize()); log.debug("Number of objects evicted from cache: " + objectCache.getCache().getCacheEventNotificationService().getElementsEvictedCounter()); for (Object key : objectCache.getCache().getKeys()) { log.debug("Object key found: " + key); } } } return object; } }

ehcache.xml

 <ehcache> <diskStore path="java.io.tmpdir"/> <defaultCache maxElementsInMemory="1000" eternal="false" timeToIdleSeconds="60" timeToLiveSeconds="300" overflowToDisk="false" memoryStoreEvictionPolicy="LRU" /> <cache name="myObjectCache" maxElementsInMemory="1000" eternal="true" timeToIdleSeconds="0" timeToLiveSeconds="0" overflowToDisk="false" diskPersistent="true" memoryStoreEvictionPolicy="LRU" /> </ehcache>

applicationContext.xml

 <bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean" />
+6
source share
1 answer

Since diskPersistent was set to true, Ehcache tried to write objects to disk after they were added to the cache. However, one of the nested objects inside the main cached object did not implement Serializable , therefore, it threw an exception to write to disk and drove the object out of the cache. This eviction did not appear in cache statistics because it was not superseded by memoryStoreEvictionPolicy .

This should have been a very simple search error, but the project did not include the slf4j-log4j12 , so the exception was swallowed and not logged. After proper processing of the log, it was immediately clear what the problem was.

Alright, live and find out, I think ...

+5
source

Source: https://habr.com/ru/post/924365/

More articles:


All Articles