[
https://issues.apache.org/jira/browse/HDFS-7454?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Vinayakumar B updated HDFS-7454:
--------------------------------
Attachment: HDFS-7454-003.patch
bq. You can reuse LongBitFormat and do the cast when necessary.
Oh, Yes, Got diverted by the name. Used same in updated patch.
bq. Another issue is that the entries of AclEntry are reconstructed every time
during permission checks, which will cause quite a bit of GC pressures in your
use case. Maybe we need to refactor the code so that the AclEntry is only
constructed in local context, or using a helper class to operate on the int
directly.
Sure. Now directly working on the {{int}} while checking for the permission.
Converting all entries only in case of access denied to append them to
exception message.
I have one doubt here..
whether we really need to append all ACL entries along with permission bits in
the exception message?
By seeing these AclEntries, caller could easily access by impersonating one of
the user in the entries? Right?
> Reduce memory footprint for AclEntries in NameNode
> --------------------------------------------------
>
> Key: HDFS-7454
> URL: https://issues.apache.org/jira/browse/HDFS-7454
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Reporter: Vinayakumar B
> Assignee: Vinayakumar B
> Attachments: HDFS-7454-001.patch, HDFS-7454-002.patch,
> HDFS-7454-003.patch
>
>
> HDFS-5620 indicated a GlobalAclSet containing unique {{AclFeature}} can be
> de-duplicated to save the memory in NameNode. However it was not implemented
> at that time.
> This Jira re-proposes same implementation, along with de-duplication of
> unique {{AclEntry}} across all ACLs.
> One simple usecase is:
> A mapreduce user's home directory with the set of default ACLs, under which
> lot of other files/directories could be created when jobs is run. Here all
> the default ACLs of parent directory will be duplicated till the explicit
> delete of those ACLs. With de-duplication,only one object will be in memory
> for the same Entry across all ACLs of all files/directories.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
