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From "Jing Zhao (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HDFS-5781) Use an array to record the mapping between FSEditLogOpCode and the corresponding byte value
Date Mon, 27 Jan 2014 18:43:38 GMT

     [ https://issues.apache.org/jira/browse/HDFS-5781?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jing Zhao updated HDFS-5781:
----------------------------

    Description: 
HDFS-5674 uses Enum.values and enum.ordinal to identify an editlog op for a given byte value.
While improving the efficiency, it may cause issue. E.g., when several new editlog ops are
added to trunk around the same time (for several different new features), it is hard to backport
the editlog ops with larger byte values to branch-2 before those with smaller values, since
there will be gaps in the byte values of the enum. 

This jira plans to still use an array to record the mapping between editlog ops and their
byte values, and allow gap between valid ops. 

  was:
HDFS-5674 uses Enum.values and enum.ordinal to identify an editlog op for a given byte value.
While improving the efficiency, it may cause issue. E.g., when several new editlog ops are
added to trunk around the same time (for several different new features), it is hard to backport
the editlog ops with larger byte values to branch-2 before those with smaller values, since
there will be gaps in the byte values of the enum. 

This jira plans to still use a map to record the mapping between editlog ops and their byte
values. 


> Use an array to record the mapping between FSEditLogOpCode and the corresponding byte
value
> -------------------------------------------------------------------------------------------
>
>                 Key: HDFS-5781
>                 URL: https://issues.apache.org/jira/browse/HDFS-5781
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: namenode
>    Affects Versions: 2.4.0
>            Reporter: Jing Zhao
>            Assignee: Jing Zhao
>            Priority: Minor
>         Attachments: HDFS-5781.000.patch, HDFS-5781.001.patch, HDFS-5781.002.patch, HDFS-5781.002.patch
>
>
> HDFS-5674 uses Enum.values and enum.ordinal to identify an editlog op for a given byte
value. While improving the efficiency, it may cause issue. E.g., when several new editlog
ops are added to trunk around the same time (for several different new features), it is hard
to backport the editlog ops with larger byte values to branch-2 before those with smaller
values, since there will be gaps in the byte values of the enum. 
> This jira plans to still use an array to record the mapping between editlog ops and their
byte values, and allow gap between valid ops. 



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