[
https://issues.apache.org/jira/browse/HDFS-7174?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14161304#comment-14161304
]
Yi Liu commented on HDFS-7174:
------------------------------
{quote}
Konstantin Shvachko wrote: I am probably late to the party, but for whatever it
worth. Did you consider using balanced trees for inode lists, something like
B-trees?
B-trees would be an excellent solution here. Since they generally use arrays in
the leaf nodes, this also gets you the benefits of tighter packing in memory. I
guess the tricky part is writing the code.
{quote}
Good point, agree. We should be careful about the memory usage during
implementation.
> Support for more efficient large directories
> --------------------------------------------
>
> Key: HDFS-7174
> URL: https://issues.apache.org/jira/browse/HDFS-7174
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Priority: Critical
> Attachments: HDFS-7174.new.patch, HDFS-7174.patch, HDFS-7174.patch
>
>
> When the number of children under a directory grows very large, insertion
> becomes very costly. E.g. creating 1M entries takes 10s of minutes. This is
> because the complexity of an insertion is O\(n\). As the size of a list
> grows, the overhead grows n^2. (integral of linear function). It also causes
> allocations and copies of big arrays.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
