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https://issues.apache.org/jira/browse/HDFS-10220?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15259384#comment-15259384
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Walter Su commented on HDFS-10220:
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bq. I think it add some readability and also because it is used twice.
I only took a peek last time. Yeah, i'm ok with that.
Another problem when I go through the details,
{code}
while(!sortedLeases.isEmpty() && sortedLeases.peek().expiredHardLimit()
&& !isMaxLockHoldToReleaseLease(start)) {
Lease leaseToCheck = sortedLeases.poll();
...
Collection<Long> files = leaseToCheck.getFiles();
...
for(Long id : leaseINodeIds) {
...
} finally {
filesLeasesChecked++;
if (isMaxLockHoldToReleaseLease(start)) {
LOG.debug("Breaking out of checkLeases() after " +
filesLeasesChecked + " file leases checked.");
break;
}
}
{code}
You can't just break the inside for-loop, the {{leaseToCheck}} has been polled
out of the queue. This will cause some files won't be closed.
> Namenode failover due to too long loking in LeaseManager.Monitor
> ----------------------------------------------------------------
>
> Key: HDFS-10220
> URL: https://issues.apache.org/jira/browse/HDFS-10220
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Reporter: Nicolas Fraison
> Assignee: Nicolas Fraison
> Priority: Minor
> Attachments: HADOOP-10220.001.patch, HADOOP-10220.002.patch,
> HADOOP-10220.003.patch, HADOOP-10220.004.patch, HADOOP-10220.005.patch,
> threaddump_zkfc.txt
>
>
> I have faced a namenode failover due to unresponsive namenode detected by the
> zkfc with lot's of WARN messages (5 millions) like this one:
> _org.apache.hadoop.hdfs.StateChange: BLOCK* internalReleaseLease: All
> existing blocks are COMPLETE, lease removed, file closed._
> On the threaddump taken by the zkfc there are lots of thread blocked due to a
> lock.
> Looking at the code, there are a lock taken by the LeaseManager.Monitor when
> some lease must be released. Due to the really big number of lease to be
> released the namenode has taken too many times to release them blocking all
> other tasks and making the zkfc thinking that the namenode was not
> available/stuck.
> The idea of this patch is to limit the number of leased released each time we
> check for lease so the lock won't be taken for a too long time period.
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