[
https://issues.apache.org/jira/browse/HDFS-5369?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Lei (Eddy) Xu updated HDFS-5369:
--------------------------------
Attachment: HDFS-5369.000.patch
This patch re-enables the negative cache behavior in user-group mapping, so
that it would not result _*long-time*_ frequently retries when the user/group
resolution service has transient issues. The difference between this patch and
HADOOP-8088 is that this patch adds another timeout for negative cached items.
Thus it should be able to differentiate the expiring times for normal case and
negative cached case.
It also reduces the error message generated from Ldap and Shell based
GroupsMappings.
It would be great to see whether this patch can fit into different cases from
[~andrew.wang], [~vinayrpet] and [~kihwal]. All feedbacks are wellcome :)
> Support negative caching of user-group mapping
> ----------------------------------------------
>
> Key: HDFS-5369
> URL: https://issues.apache.org/jira/browse/HDFS-5369
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Affects Versions: 2.2.0
> Reporter: Andrew Wang
> Attachments: HDFS-5369.000.patch
>
>
> We've seen a situation at a couple of our customers where interactions from
> an unknown user leads to a high-rate of group mapping calls. In one case,
> this was happening at a rate of 450 calls per second with the shell-based
> group mapping, enough to severely impact overall namenode performance and
> also leading to large amounts of log spam (prints a stack trace each time).
> Let's consider negative caching of group mapping, as well as quashing the
> rate of this log message.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
