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https://issues.apache.org/jira/browse/HDFS-13097?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16354035#comment-16354035
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Rakesh R commented on HDFS-13097:
---------------------------------
Attached new patch addressing the above comments. Please review it again.
Thanks!
> [SPS]: Fix the branch review comments(Part1)
> --------------------------------------------
>
> Key: HDFS-13097
> URL: https://issues.apache.org/jira/browse/HDFS-13097
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Affects Versions: HDFS-10285
> Reporter: Surendra Singh Lilhore
> Assignee: Surendra Singh Lilhore
> Priority: Major
> Attachments: HDFS-13097-HDFS-10285.01.patch,
> HDFS-13097-HDFS-10285.02.patch, HDFS-13097-HDFS-10285.03.patch
>
>
> Fix the branch review comment. Please refer HDFS-10285 to see more detailed
> [discussion|https://issues.apache.org/jira/browse/HDFS-10285?focusedCommentId=16347472&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16347472].
> *Comment-1)*
> {quote}BlockManager
> Shouldn’t spsMode be volatile? Although I question why it’s here.
> {quote}
> [Rakesh's reply] Agreed, will do the changes.
> *Comment-2)*
> {quote}Adding SPS methods to this class implies an unexpected coupling of the
> SPS service to the block manager. Please move them out to prove it’s not
> tightly coupled.
> {quote}
> [Rakesh's reply] Agreed. I'm planning to create
> {{StoragePolicySatisfyManager}} and keep all the related apis over there.
> *Comment-5)*
> {quote}DatanodeDescriptor
> Why use a synchronized linked list to offer/poll instead of BlockingQueue?
> {quote}
> [Rakesh's reply] Agreed, will do the changes.
> *Comment-8)*
> {quote}DFSUtil
> DFSUtil.removeOverlapBetweenStorageTypes and {{DFSUtil.getSPSWorkMultiplier
> }}. These aren’t generally useful methods so why are they in DFSUtil? Why
> aren’t they in the only calling class StoragePolicySatisfier?
> {quote}
> [Rakesh's reply] Agreed, Will do the changes.
> *Comment-11)*
> {quote}HdfsServerConstants
> The xattr is called user.hdfs.sps.xattr. Why does the xattr name actually
> contain the word “xattr”?
> {quote}
> [Rakesh's reply] Sure, will remove “xattr” word.
> *Comment-12)*
> {quote}NameNode
> Super trivial but using the plural pronoun “we” in this exception message is
> odd. Changing the value isn’t a joint activity.
> For enabling or disabling storage policy satisfier, we must pass either
> none/internal/external string value only
> {quote}
> [Rakesh's reply] oops, sorry for the mistake. Will change it.
> *Comment-15)*
> {quote}FSDirSatisfyStoragePolicyOp
> satisfyStoragePolicy errors if the xattr is already present. Should this be
> a no-op? A client re-requesting a storage policy correction probably
> shouldn't fail.
> unprotectedSatisfyStoragePolicy is called prior to xattr updates, which calls
> addSPSPathId. To avoid race conditions or inconsistent state if the xattr
> fails, should call addSPSPathId after xattrs are successfully updated.
> inodeHasSatisfyXAttr calls getXAttrFeature then immediately shorts out if the
> inode isn't a file. Should do file check first to avoid unnecessary
> computation.
> In general, not fond of unnecessarily guava. Instead of
> newArrayListWithCapacity + add, standard Arrays.asList(item) is more succinct.
> {quote}
> [Rakesh'r reply] Agreed, will do the changes.
> *Comment-16)*
> {quote}FSDirStatAndListOp
> Not sure why javadoc was changed to add needLocation. It's already present
> and now doubled up.
> {quote}
> [Rakesh'r reply] Agreed, will correct it.
>
> *Comment-18)*
> {quote}DFS_MOVER_MOVERTHREADS_DEFAULT is 1000 per DN? If the DN is
> concurrently doing 1000 moves, it's not in a good state, disk io is probably
> saturated, and this will only make it much worse. 10 is probably more than
> sufficient.
> {quote}
> [Rakesh'r reply] Agreed, will make it to smaller value 10.
>
> *Comment-22)*
> {quote}StoragePolicySatisifier
> Should handleException use a double-checked lock to avoid synchronization?
> Unexpected exceptions should be a rarity, right?
> Speaking of which, it’s not safe to ignore all Throwable in the run loop!
> You have no idea if data structures are in a sane or consistent state.
> {quote}
> [Rakesh'r reply] Agreed, will do the changes.
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