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Lei (Eddy) Xu commented on HADOOP-10755: ---------------------------------------- Hey, [~andrew.wang] and [~kihwal], could you take another look on this patch? Thanks! > Support negative caching of user-group mapping > ---------------------------------------------- > > Key: HADOOP-10755 > URL: https://issues.apache.org/jira/browse/HADOOP-10755 > Project: Hadoop Common > Issue Type: Improvement > Components: security > Affects Versions: 2.2.0 > Reporter: Andrew Wang > Assignee: Lei (Eddy) Xu > Attachments: HADOOP-10755.000.patch, HADOOP-10755.001.patch, > HADOOP-10755.002.patch, 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)