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Posted to common-issues@hadoop.apache.org by "Haibo Chen (JIRA)" <ji...@apache.org> on 2017/10/10 21:57:00 UTC
[jira] [Commented] (HADOOP-12436) GlobPattern regex library has
performance issues with wildcard characters
[ https://issues.apache.org/jira/browse/HADOOP-12436?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16199434#comment-16199434 ]
Haibo Chen commented on HADOOP-12436:
-------------------------------------
[~aw] [~mattpaduano] This seems an incompatible change given GlobFilter and RegexFilter are Public Evolving. Hence, I have added an incompatible tag. Feel free to remove it if you disagree
> GlobPattern regex library has performance issues with wildcard characters
> -------------------------------------------------------------------------
>
> Key: HADOOP-12436
> URL: https://issues.apache.org/jira/browse/HADOOP-12436
> Project: Hadoop Common
> Issue Type: Improvement
> Components: fs
> Affects Versions: 2.2.0, 2.7.1
> Reporter: Matthew Paduano
> Assignee: Matthew Paduano
> Fix For: 3.0.0-alpha1
>
> Attachments: HADOOP-12436.01.patch, HADOOP-12436.02.patch, HADOOP-12436.03.patch, HADOOP-12436.04.patch, HADOOP-12436.05.patch
>
>
> java.util.regex classes have performance problems with certain wildcard patterns. Namely, consecutive * characters in a file name (not properly escaped as literals) will cause commands such as "hadoop fs -ls file******name" to consume 100% CPU and probably never return in a reasonable time (time scales with number of *'s).
> Here is an example:
> {noformat}
> hadoop fs -touchz /user/mattp/job_1429571161900_4222-1430338332599-tda%2D%2D\\\+\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\*\\\+\\\+\\\+...%270%27%28Stage-1430338580443-39-2000-SUCCEEDED-production%2Dhigh-1430338340360.jhist
> hadoop fs -ls /user/mattp/job_1429571161900_4222-1430338332599-tda%2D%2D+******************************+++...%270%27%28Stage-1430338580443-39-2000-SUCCEEDED-production%2Dhigh-1430338340360.jhist
> {noformat}
> causes:
> {noformat}
> PID COMMAND %CPU TIME
> 14526 java 100.0 01:18.85
> {noformat}
> Not every string of *'s causes this, but the above filename reproduces this reliably.
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