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https://issues.apache.org/jira/browse/HADOOP-3620?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12614598#action_12614598
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rangadi edited comment on HADOOP-3620 at 7/17/08 6:19 PM:
---------------------------------------------------------------
One way to move the resolution out of global lock :
resolveNetworkLocation does not strictly need DatanodeDescriptor.
So regeisterDatanode() could look something like :
{code}
public void registerDatanode(DatanodeRegistration nodeReg) throws IOException {
String networkLocation = resolveNeworklocation(nodeReg.getHost());
internalRegisterDatanode(nodeReg, networkLocation); //holds global lock.
}
{code}
Does the above work?
Note that pre-resolving hosts in include file might not help start up since
* resolving serially at the beginning still increases the start up time.
* "normalizing host names" does multiple DNS resolves.
was (Author: rangadi):
One way to move the resolution out of global lock :
resolveNetworkLocation does not strictly need DatanodeDescriptor.
So regeisterDatanode() could look something like :
{code}
public void public synchronized void registerDatanode(DatanodeRegistration
nodeReg)
throws IOException {
String networkLocation = resolveNeworklocation(nodeReg.getHost());
internalRegisterDatanode(nodeReg, networkLocation); //holds global lock.
}
{code}
Does the above work?
Note that pre-resolving hosts in include file might not help start up since
* resolving serially at the beginning still increases the start up time.
* "normalizing host names" does multiple DNS resolves.
> Namenode should synchronously resolve a datanode's network location when the
> datanode registers
> -----------------------------------------------------------------------------------------------
>
> Key: HADOOP-3620
> URL: https://issues.apache.org/jira/browse/HADOOP-3620
> Project: Hadoop Core
> Issue Type: Improvement
> Components: dfs
> Affects Versions: 0.18.0
> Reporter: Hairong Kuang
> Assignee: Hairong Kuang
> Fix For: 0.19.0
>
> Attachments: netResolution.patch, netResolution1.patch,
> netResolution2.patch, netResolution3.patch, netResolution4.patch
>
>
> Release 0.18.0 removes the rpc timeout. So the namenode is ok to resolve a
> datanode's network location when the datanode registers. This could remove
> quite a lot of unnecessary code in both datanode and namenode to handle
> asynchronous network location resolution and avoid many potential bugs.
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