[jira] [Updated] (HDFS-5781) Use an array to record the mapping between FSEditLogOpCode and the corresponding byte value

["Jing Zhao (JIRA)" <ji...@apache.org>]

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

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

    Summary: Use an array to record the mapping between FSEditLogOpCode and the corresponding byte value  (was: Use a map to record the mapping between FSEditLogOpCode and the corresponding byte value)

> 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 a map to record the mapping between editlog ops and their byte values. 



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