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https://issues.apache.org/jira/browse/HDFS-13443?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16471826#comment-16471826
]
Vinayakumar B commented on HDFS-13443:
--------------------------------------
Hi [~arshad.mohammad], thanks for much required patch. Please find some
comments here.
1. Refresh() should actually refresh MountTableResolver for user operations,
otherwise users will continue to get exceptions.
{{MountTableResolver#loadCache()}} internally refreshes MountTable entries as
well.
{{RouterAdminServer#refreshMountTableEntries()}} can be implemented as below
to refresh MountTableResolver directly. and skip MountTableStoreImpl
implementation, as it never be used.
{code:title=RouterAdminServer.java}
@Override
public RefreshMountTableEntriesResponse refreshMountTableEntries(
RefreshMountTableEntriesRequest request) throws IOException {
boolean result = getRouter().getStateStore()
.loadCache(MountTableResolver.class, true);
RefreshMountTableEntriesResponse response = RefreshMountTableEntriesResponse
.newInstance();
response.setResult(result);
return response;
}
{code}
2. There is no need of Two separate threads to call local and remote. Both can
be handled in same Class (i.e.
MountTableRefreshThread ) as below.
i. Current patch passes 'MountTableStore' reference to LocalRefresh thread
and 'RouterRpcClient' reference to Remote refresh thread. Instead pass
'MountTableManager' reference to a same thread.
a. In case of Local call, pass RouterAdminServer reference as
MountTableManager
b. In case of remote pass client.getMountTableManager() which is proxy to
Remote Admin's MountTableManager;
{code:title=MountTableRefreshThread.java}
public MountTableRefreshThread(MountTableManager client, String adminAddress)
{
this.client = client;
this.adminAddress = adminAddress;
setName("MountTableRefresh_" + adminAddress);
setDaemon(true);
}
{code}
{code:title=MountTableRefreshService#refresh}
MountTableManager mountTableManager;
if (isLocalAdmin(adminAddress)) {
mountTableManager = router.getAdminServer();
} else {
mountTableManager = client.getMountTableManager();
}
refreshThreads.add(new MountTableRefreshThread(mountTableManager,
adminAddress));
{code}
> RBF: Update mount table cache immediately after changing (add/update/remove)
> mount table entries.
> -------------------------------------------------------------------------------------------------
>
> Key: HDFS-13443
> URL: https://issues.apache.org/jira/browse/HDFS-13443
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: fs
> Reporter: Mohammad Arshad
> Assignee: Mohammad Arshad
> Priority: Major
> Labels: RBF
> Attachments: HDFS-13443-branch-2.001.patch,
> HDFS-13443-branch-2.002.patch, HDFS-13443.001.patch, HDFS-13443.002.patch,
> HDFS-13443.003.patch, HDFS-13443.004.patch, HDFS-13443.005.patch,
> HDFS-13443.006.patch, HDFS-13443.007.patch, HDFS-13443.008.patch,
> HDFS-13443.009.patch
>
>
> Currently mount table cache is updated periodically, by default cache is
> updated every minute. After change in mount table, user operations may still
> use old mount table. This is bit wrong.
> To update mount table cache, maybe we can do following
> * *Add refresh API in MountTableManager which will update mount table cache.*
> * *When there is a change in mount table entries, router admin server can
> update its cache and ask other routers to update their cache*. For example if
> there are three routers R1,R2,R3 in a cluster then add mount table entry API,
> at admin server side, will perform following sequence of action
> ## user submit add mount table entry request on R1
> ## R1 adds the mount table entry in state store
> ## R1 call refresh API on R2
> ## R1 calls refresh API on R3
> ## R1 directly freshest its cache
> ## Add mount table entry response send back to user.
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