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https://issues.apache.org/jira/browse/HBASE-15992?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15321282#comment-15321282
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Andrew Purtell commented on HBASE-15992:
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Thanks for filing this [~haridsv]. I agree we should preserve information on
the original cause and be smarter about what type of exception to rethrow where
the failure indicates a more permanent condition. Do you plan on working on a
patch or would you like to hand it off for someone else to look at?
> Preserve original KeeperException when converted to external exceptions
> -----------------------------------------------------------------------
>
> Key: HBASE-15992
> URL: https://issues.apache.org/jira/browse/HBASE-15992
> Project: HBase
> Issue Type: Brainstorming
> Components: hbase
> Affects Versions: 0.98.14
> Reporter: Hari Krishna Dara
> Priority: Minor
> Labels: client, client-auth, zookeeper
>
> During an investigation in which we were seeing unexpected
> {{NoServerForRegionException}} errors, the root cause turned out to be a
> {{KeeperException}} that got lost and so resulted in a misleading top level
> indication.
> The underlying exception with partial stacktrace is this:
> {noformat}
> org.apache.zookeeper.KeeperException$AuthFailedException: KeeperErrorCode =
> AuthFailed for /hbase/meta-region-server
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:123)
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
> at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1289)
> at
> org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.getData(RecoverableZooKeeper.java:359)
> at org.apache.hadoop.hbase.zookeeper.ZKUtil.getData(ZKUtil.java:684)
> at
> org.apache.hadoop.hbase.zookeeper.ZKUtil.blockUntilAvailable(ZKUtil.java:2032)
> at
> org.apache.hadoop.hbase.zookeeper.MetaRegionTracker.blockUntilAvailable(MetaRegionTracker.java:203)
> at
> org.apache.hadoop.hbase.client.ZooKeeperRegistry.getMetaRegionLocation(ZooKeeperRegistry.java:58)
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateMeta(HConnectionManager.java:1209)
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:1175)
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegionInMeta(HConnectionManager.java:1301)
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:1178)
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:1135)
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionLocation(HConnectionManager.java:976)
> {noformat}
> Here is some additional information:
> * The exception first gets caught
> [here|https://github.com/apache/hbase/blob/rel/0.98.14/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/RecoverableZooKeeper.java#L366]
> * It gets logged and rethrown from
> [here|https://github.com/apache/hbase/blob/rel/0.98.14/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/RecoverableZooKeeper.java#L279]
> * It gets caught again, logged and rethrown
> [here|https://github.com/apache/hbase/blob/rel/0.98.14/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java#L693]
> * This finally gets caught and rethrown as InterruptedException
> [here|https://github.com/apache/hbase/blob/rel/0.98.14/hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java#L2037]
> When thrown as {{InterruptedException}}, the cause is lost, so [the code
> catching
> it|https://github.com/apache/hbase/blob/rel/0.98.14/hbase-client/src/main/java/org/apache/hadoop/hbase/client/ZooKeeperRegistry.java#L65]
> can't (and currently doesn't) determine the cause. Perhaps the exception
> should be preserved and passed on to [the
> caller|https://github.com/apache/hbase/blob/rel/0.98.14/hbase-client/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java#L1312]
> such that it is available when finally the {{NoServerForRegionException}} is
> thrown
> [here|https://github.com/apache/hbase/blob/rel/0.98.14/hbase-client/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java#L1281].
> Alternatively, a more meaningful exception could also be thrown instead of a
> misleading {{NoServerForRegionException}}, especially in cases where the
> failure indicates a more permanent condition.
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