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Posted to notifications@accumulo.apache.org by "Christopher Tubbs (JIRA)" <ji...@apache.org> on 2013/05/22 23:30:20 UTC

[jira] [Updated] (ACCUMULO-1449) Connector/ZooCache code enters infinite loop when Zookeeper connection lost.

     [ https://issues.apache.org/jira/browse/ACCUMULO-1449?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Christopher Tubbs updated ACCUMULO-1449:
----------------------------------------

    Fix Version/s: 1.6.0
    
> Connector/ZooCache code enters infinite loop when Zookeeper connection lost.
> ----------------------------------------------------------------------------
>
>                 Key: ACCUMULO-1449
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-1449
>             Project: Accumulo
>          Issue Type: Bug
>          Components: client
>    Affects Versions: 1.5.0
>         Environment: accumulo-1.5.0-RC4, zookeeper-3.4.5, hadoop-1.0.4, CentOS 6.4
>            Reporter: Luke Brassard
>             Fix For: 1.6.0, 1.5.1
>
>
> While using 1.5.0-RC4 a long-lived {{Connector}} went into an infinite loop of Zookeeper "ConnectionLoss" and "Session expired" failures. In a multithreaded application, all using the same {{Connector}}, there were errors whenever there were calls to {{conn.createScanner()}} and {{conn.createBatchScanner()}}. Here are a couple stacktraces:
> {code}
> 013-05-22 09:12:28,250 [zookeeper.ZooCache] WARN : Zookeeper error, will retry
> org.apache.zookeeper.KeeperException$SessionExpiredException: KeeperErrorCode = Session expired for /accumulo/5e982cc9-6959-4064-9712-2ff3dc1003d8
> 	at org.apache.zookeeper.KeeperException.create(KeeperException.java:127)
> 	at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
> 	at org.apache.zookeeper.ZooKeeper.exists(ZooKeeper.java:1041)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache$2.run(ZooCache.java:208)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache.retry(ZooCache.java:130)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:233)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:188)
> 	at org.apache.accumulo.core.client.ZooKeeperInstance.getInstanceID(ZooKeeperInstance.java:151)
> 	at org.apache.accumulo.core.zookeeper.ZooUtil.getRoot(ZooUtil.java:24)
> 	at org.apache.accumulo.core.client.impl.Tables.getMap(Tables.java:46)
> 	at org.apache.accumulo.core.client.impl.Tables.getNameToIdMap(Tables.java:78)
> 	at org.apache.accumulo.core.client.impl.Tables.getTableId(Tables.java:64)
> 	at org.apache.accumulo.core.client.impl.ConnectorImpl.getTableId(ConnectorImpl.java:75)
> 	at org.apache.accumulo.core.client.impl.ConnectorImpl.createScanner(ConnectorImpl.java:137)
> {code}    
> {code}    
> 2013-05-22 09:12:23,849 [zookeeper.ZooCache] WARN : Zookeeper error, will retry
> org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/5e982cc9-6959-4064-9712-2ff3dc1003d8
> 	at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
> 	at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
> 	at org.apache.zookeeper.ZooKeeper.exists(ZooKeeper.java:1041)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache$2.run(ZooCache.java:208)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache.retry(ZooCache.java:130)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:233)
> 	at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:188)
> 	at org.apache.accumulo.core.client.ZooKeeperInstance.getInstanceID(ZooKeeperInstance.java:151)
> 	at org.apache.accumulo.core.zookeeper.ZooUtil.getRoot(ZooUtil.java:24)
> 	at org.apache.accumulo.core.client.impl.Tables.getMap(Tables.java:46)
> 	at org.apache.accumulo.core.client.impl.Tables.getNameToIdMap(Tables.java:78)
> 	at org.apache.accumulo.core.client.impl.Tables.getTableId(Tables.java:64)
> 	at org.apache.accumulo.core.client.impl.ConnectorImpl.getTableId(ConnectorImpl.java:75)
> 	at org.apache.accumulo.core.client.impl.ConnectorImpl.createBatchScanner(ConnectorImpl.java:89)
> {code}
> The method {{ZooCache.retry(ZooRunnable op)}} (ZooCache.java:128) has a {{while(true)}} loop that should probably have a max retries or timeout that will eventually cause the method to throw an exception that can be handled appropriately by the client. As it is currently, this loop will never be exited when Zookeeper continues to error.
> Note: There may have been a network hiccup that triggered the bug, but there was no way to recover without restarting the application.

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