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From "Todd Lipcon (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HADOOP-7115) Add a cache for getpwuid_r and getpwgid_r calls
Date Wed, 07 Nov 2012 21:50:13 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-7115?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13492733#comment-13492733
] 

Todd Lipcon commented on HADOOP-7115:
-------------------------------------

- why is cacheTimeout volatile? You're already synchronizing on the class inside {{ensureInitialized}}.
- instead of {{ensureInitialized}}, why not initialize the configuration in the existing static
{...} block?
- instead of using ints for {{USER}} and {{GROUP}}, how about an enum like this:

{code}
enum IdCache {
  USERNAME,
  GROUP;

  ConcurrentHashMap<Integer, CachedName> cache =
    new ConcurrentHashMap<Integer, CachedName>();
}

...

private static String getName(IdCache cache, int id) {
  CachedName cachedName = cache.cache.get(id);
  ...
}
{code}

this way you get typesafety, and you can just stringify the {{IdCache}} instance to get a
printable name


Otherwise looks good to me
                
> Add a cache for getpwuid_r and getpwgid_r calls
> -----------------------------------------------
>
>                 Key: HADOOP-7115
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7115
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 0.22.0, 2.0.2-alpha, 0.23.4
>            Reporter: Arun C Murthy
>            Assignee: Alejandro Abdelnur
>             Fix For: 0.22.1, 2.0.3-alpha
>
>         Attachments: h-7115.1.patch, hadoop-7115-0.22.patch, hadoop-7115-0.22.patch,
HADOOP-7115.patch
>
>
> As discussed in HADOOP-6978, a cache helps a lot.

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