NodeInvocationDelegate.addChild(Fqn) can return null in some circumstances contrary to JavaDoc for Node.addChild(Fqn) --------------------------------------------------------------------------------------------------------------------- Key: JBCACHE-1584 URL: https://issues.jboss.org/browse/JBCACHE-1584 Project: JBoss Cache Issue Type: Bug Security Level: Public(Everyone can see) Components: Locking Affects Versions: 3.1.0.GA Reporter: Andrew Duckworth Assignee: Manik Surtani NodeInvocationDelegate.addChild(Fqn) can return null in some circumstances: It seems if in a multi-threaded environment with a slow JDBC cache loader the following sequence can occur: 1. Thread 1 calls NodeInvocationDelegate.addChild(Fqn), node does not exist and is created locally getChild() == null put(fqn) // node now exists on DB 2. Thread 2 calls NodeInvocationDelegate.removeChild(Fqn) results in node being deleted from DB 3. Thread 1 returns getChild(fqn) as the result of the add, however this propagates all the way down to the cache loader and null is returned violating the contract of addChild which indicates a non-null return value. see the following log4j log entries for more details: [Entry id=40225, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40226, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT '1' FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40227, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 is false <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40228, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40229, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT '1' FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40230, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 is false <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40231, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.invocation.NodeInvocationDelegate, message=Child is null; creating. <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40232, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=loadNode name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40233, date=2010-06-04 14:43:24,983, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT node FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40234, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=put name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 attr={} <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40235, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40236, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT '1' FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40237, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 is false <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40238, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=addNewSubtree name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 attr={} <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40239, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=insertNode name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 dataMap={} <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40240, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [INSERT INTO jbosscache (fqn, node, parent) SELECT ?, ?, ? FROM jbosscache_D WHERE NOT EXISTS (SELECT fqn FROM jbosscache WHERE fqn = ?)] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40241, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40242, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT '1' FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40243, date=2010-06-04 14:43:24,998, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache is true <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40244, date=2010-06-04 14:43:24,998, level=DEBUG, thread=FestivalScheduler_Worker-1, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:workflow_identity thd:91]]></log4j:NDC> ] [Entry id=40245, date=2010-06-04 14:43:24,998, level=DEBUG, thread=FestivalScheduler_Worker-1, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT '1' FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:workflow_identity thd:91]]></log4j:NDC> ] [Entry id=40246, date=2010-06-04 14:43:24,998, level=DEBUG, thread=FestivalScheduler_Worker-1, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 is true <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:workflow_identity thd:91]]></log4j:NDC> ] [Entry id=40247, date=2010-06-04 14:43:24,998, level=DEBUG, thread=FestivalScheduler_Worker-1, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=loadNode name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:workflow_identity thd:91]]></log4j:NDC> ] [Entry id=40248, date=2010-06-04 14:43:24,998, level=DEBUG, thread=FestivalScheduler_Worker-1, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT node FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:workflow_identity thd:91]]></log4j:NDC> ] [Entry id=40249, date=2010-06-04 14:43:24,998, level=DEBUG, thread=FestivalScheduler_Worker-1, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [DELETE FROM jbosscache WHERE fqn = ? OR fqn LIKE ? ESCAPE '^'] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503], [/com.sandstone^_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503/%] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:workflow_identity thd:91]]></log4j:NDC> ] [Entry id=40250, date=2010-06-04 14:43:25,014, level=INFO, thread=WebContainer : 15, emitter=com.sandstone_tech.workflow.UPGRADING_WORKFLOW_SPECIFICATION, message=Upgrading the workflow specification for instance com.sandstone_tech.workflow.WorkflowInstImpl: name = FldFiordland: id = 16343 from version 352 to 357. <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:oceaniatst\aumlafulfil042 sess:b32l3DIPtxjOS8yE2pjRNta thd:1771]]></log4j:NDC> ] [Entry id=40251, date=2010-06-04 14:43:25,170, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.invocation.NodeInvocationDelegate, message=Created. Now getting again. <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40252, date=2010-06-04 14:43:25,170, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40253, date=2010-06-04 14:43:25,170, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=Executing SQL statement [SELECT '1' FROM jbosscache WHERE fqn = ?] with params [/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503] <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40254, date=2010-06-04 14:43:25,170, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.loader.BatchJDBCCacheLoader, message=exists name=/com.sandstone_tech.workflow.WorkflowManager.TaskOwnershipCache/4440503 is false <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40255, date=2010-06-04 14:43:25,170, level=DEBUG, thread=WebContainer : 19, emitter=org.jboss.cache.invocation.NodeInvocationDelegate, message=Got child null <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> ] [Entry id=40256, date=2010-06-04 14:43:25,170, level=ERROR, thread=WebContainer : 19, emitter=com.sandstone_tech.framework.cluster.jbosscache.NodePerKeyMap, message=Unable to put 4,440,503 <log4j:NDC><![CDATA[sid:7564@WASAUQAADT020 user:auser sess:9RJ3MT6YXP5BJj57v4NYnaA thd:1829]]></log4j:NDC> <log4j:throwable><![CDATA[java.lang.NullPointerException at com.sandstone_tech.framework.cluster.jbosscache.NodePerKeyMap.put0(NodePerKeyMap.java:207) at com.sandstone_tech.framework.cluster.jbosscache.NodePerKeyMap.put(NodePerKeyMap.java:183)