[jira] Commented: (DERBY-3731) Improve calculation of refSize in ClassSize.java

["Kristian Waagan (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DERBY-3731?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12625656#action_12625656 ] 

Kristian Waagan commented on DERBY-3731:
----------------------------------------

The 1c patch hasn't been ported to 10.4, nor 10.3.
I don't think the patch has caused any serious problems on trunk. With the patch, refSize is more likely to be correct.

The following tasks remain:
 a) Document the required privileges.
 b) Add the privileges to the template policy file.

The permissions to read the properties are not mandatory. If they are missing, the old heuristic will be used.


> Improve calculation of refSize in ClassSize.java 
> -------------------------------------------------
>
>                 Key: DERBY-3731
>                 URL: https://issues.apache.org/jira/browse/DERBY-3731
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 10.5.0.0
>            Reporter: Kathey Marsden
>            Assignee: Kristian Waagan
>            Priority: Minor
>             Fix For: 10.4.2.0, 10.5.0.0
>
>         Attachments: derby-3731-1a-refsize_from_properties.diff, derby-3731-1b-refsize_from_properties.diff, derby-3731-1b-refsize_from_properties.stat, derby-3731-1c-refsize_from_properties.diff, DERBY-3731_diff.txt
>
>
> java/engine/org/apache/derby/iapi/services/cache/ClassSize.java has a static code block which calculates the size of a reference for the architecture.  This code could be improved by adding garbage collection before measuring memory, to give a consistent  reading.     Also there have been suggestions that we use os.arch or sun.arch.data.model to make the measurement more reliable, especially on 64bit machines.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.