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Posted to notifications@accumulo.apache.org by "Eric Newton (JIRA)" <ji...@apache.org> on 2014/11/14 18:30:33 UTC
[jira] [Commented] (ACCUMULO-3336) ZK session reconnect still
results in loss of ZK lock
[ https://issues.apache.org/jira/browse/ACCUMULO-3336?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14212512#comment-14212512 ]
Eric Newton commented on ACCUMULO-3336:
---------------------------------------
Do you have the logs prior to these events?
Here's an alternative interpretation:
* zk client loses session due to java gc pauses, or swap, or the universe hates us
* client wakes up, gets disconnect
* client gets the session lost event
* lots of other zookeeper checks fail as the process dies
In particular:
bq. WARN : GC pause checker not called in a timely fashion. Expected every 5.0 seconds but was 43.1 seconds since last check
> ZK session reconnect still results in loss of ZK lock
> -----------------------------------------------------
>
> Key: ACCUMULO-3336
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3336
> Project: Accumulo
> Issue Type: Bug
> Components: zookeeper
> Affects Versions: 1.5.2, 1.6.1
> Reporter: Josh Elser
> Fix For: 1.7.0
>
>
> Saw the following
> {noformat}
> 2014-11-14 08:38:30,612 [zookeeper.DistributedWorkQueue] INFO : Got unexpected zookeeper event: None for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/bulk_failed_copyq
> 2014-11-14 08:38:30,621 [zookeeper.ZooCache] WARN : Saw (possibly) transient exception communicating with ZooKeeper, will retry
> org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/config/tserver.compaction.warn.time
> 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:1045)
> at org.apache.accumulo.fate.zookeeper.ZooCache$2.run(ZooCache.java:260)
> at org.apache.accumulo.fate.zookeeper.ZooCache.retry(ZooCache.java:157)
> at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:285)
> at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:232)
> at org.apache.accumulo.server.conf.ZooConfiguration.get(ZooConfiguration.java:96)
> at org.apache.accumulo.server.conf.ZooConfiguration._get(ZooConfiguration.java:65)
> at org.apache.accumulo.server.conf.ZooConfiguration.get(ZooConfiguration.java:90)
> at org.apache.accumulo.core.conf.AccumuloConfiguration.getTimeInMillis(AccumuloConfiguration.java:136)
> at org.apache.accumulo.tserver.CompactionWatcher.run(CompactionWatcher.java:84)
> at org.apache.accumulo.server.util.time.SimpleTimer$LoggingTimerTask.run(SimpleTimer.java:42)
> at java.util.TimerThread.mainLoop(Timer.java:555)
> at java.util.TimerThread.run(Timer.java:505)
> 2014-11-14 08:38:30,672 [zookeeper.DistributedWorkQueue] INFO : Got unexpected zookeeper event: None for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/recovery
> 2014-11-14 08:38:30,672 [zookeeper.ZooLock] DEBUG: event null None Disconnected
> 2014-11-14 08:38:31,484 [zookeeper.ZooReader] WARN : Saw (possibly) transient exception communicating with ZooKeeper
> org.apache.zookeeper.KeeperException$SessionExpiredException: KeeperErrorCode = Session expired for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/tservers/ip-172-31-13-177:37709
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:127)
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
> at org.apache.zookeeper.ZooKeeper.exists(ZooKeeper.java:1045)
> at org.apache.accumulo.fate.zookeeper.ZooReader.getStatus(ZooReader.java:109)
> at org.apache.accumulo.fate.zookeeper.ZooLock.process(ZooLock.java:381)
> at org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:522)
> at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:498)
> 2014-11-14 08:38:31,484 [zookeeper.ZooCache] WARN : Saw (possibly) transient exception communicating with ZooKeeper, will retry
> org.apache.zookeeper.KeeperException$SessionExpiredException: KeeperErrorCode = Session expired for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/tables/!0/namespace
> 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:1045)
> at org.apache.accumulo.fate.zookeeper.ZooCache$2.run(ZooCache.java:260)
> at org.apache.accumulo.fate.zookeeper.ZooCache.retry(ZooCache.java:157)
> at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:285)
> at org.apache.accumulo.fate.zookeeper.ZooCache.get(ZooCache.java:232)
> at org.apache.accumulo.core.client.impl.Tables.getNamespaceId(Tables.java:304)
> at org.apache.accumulo.server.conf.TableParentConfiguration.getNamespaceId(TableParentConfiguration.java:47)
> at org.apache.accumulo.server.conf.NamespaceConfiguration.getPath(NamespaceConfiguration.java:85)
> at org.apache.accumulo.server.conf.NamespaceConfiguration.get(NamespaceConfiguration.java:98)
> at org.apache.accumulo.server.conf.ZooCachePropertyAccessor.get(ZooCachePropertyAccessor.java:107)
> at org.apache.accumulo.server.conf.TableConfiguration.get(TableConfiguration.java:103)
> at org.apache.accumulo.core.conf.AccumuloConfiguration.getCount(AccumuloConfiguration.java:193)
> at org.apache.accumulo.tserver.TabletServer$MajorCompactor.run(TabletServer.java:2636)
> at org.apache.accumulo.core.util.LoggingRunnable.run(LoggingRunnable.java:34)
> at java.lang.Thread.run(Thread.java:745)
> 2014-11-14 08:38:31,484 [zookeeper.Retry] DEBUG: Sleeping for 250ms before retrying operation
> 2014-11-14 08:38:31,485 [zookeeper.ZooSession] DEBUG: Removing closed ZooKeeper session to localhost:12644
> 2014-11-14 08:38:31,485 [zookeeper.ZooSession] DEBUG: Connecting to localhost:12644 with timeout 30000 with auth
> 2014-11-14 08:38:31,588 [zookeeper.ZooSession] DEBUG: Removing closed ZooKeeper session to localhost:12644
> 2014-11-14 08:38:31,588 [zookeeper.ZooSession] DEBUG: Connecting to localhost:12644 with timeout 30000 with auth
> 2014-11-14 08:38:31,692 [tserver.TabletServer] DEBUG: gc ParNew=0.10(+0.04) secs ConcurrentMarkSweep=0.05(+0.00) secs freemem=118,013,904(+6,412,200) totalmem=129,761,280
> 2014-11-14 08:38:31,692 [tserver.TabletServer] WARN : GC pause checker not called in a timely fashion. Expected every 5.0 seconds but was 43.1 seconds since last check
> 2014-11-14 08:38:31,700 [zookeeper.DistributedWorkQueue] DEBUG: Looking for work in /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/bulk_failed_copyq
> 2014-11-14 08:38:31,701 [zookeeper.DistributedWorkQueue] DEBUG: Looking for work in /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/recovery
> 2014-11-14 08:38:31,715 [tserver.TabletServer] DEBUG: ScanSess tid 172.31.13.177:35935 !0 1 entries in 0.03 secs, nbTimes = [24 24 24.00 1]
> 2014-11-14 08:38:31,737 [trace.ZooTraceClient] DEBUG: Scanning trace hosts in zookeeper: /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/tracers
> 2014-11-14 08:38:31,737 [trace.ZooTraceClient] DEBUG: Trace hosts: []
> 2014-11-14 08:38:31,739 [zookeeper.DistributedWorkQueue] INFO : Got unexpected zookeeper event: None for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/replication/workqueue
> 2014-11-14 08:38:31,739 [zookeeper.DistributedWorkQueue] INFO : Got unexpected zookeeper event: None for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/bulk_failed_copyq
> 2014-11-14 08:38:31,739 [zookeeper.DistributedWorkQueue] INFO : Got unexpected zookeeper event: None for /accumulo/00f38e67-3c29-4cf0-a394-f423a0b33b6b/recovery
> 2014-11-14 08:38:31,739 [zookeeper.ZooSession] DEBUG: Session expired, state of current session : Expired
> 2014-11-14 08:38:31,739 [zookeeper.ZooLock] DEBUG: event null None Expired
> 2014-11-14 08:38:31,741 [tserver.TabletServer] FATAL: Lost tablet server lock (reason = SESSION_EXPIRED), exiting.
> {noformat}
> ZooKeeper code appears to had disconnected, closed the disconnected connection and then opened a new session. However, the ZooLock, IIRC, didn't reconnect and hung the tserver.
> If we want to support this, it might require rehashing some of the ZooLock code (to prevent the tserver from processing while the tserver doesn't have its lock).
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