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From "Kristian Waagan (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-4519) Infinite loop in StreamFileContainer.writeColumn
Date Wed, 20 Jan 2010 10:34:54 GMT

     [ https://issues.apache.org/jira/browse/DERBY-4519?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Kristian Waagan updated DERBY-4519:

    Attachment: derby-4519-2a-infinite_loop_fixes.diff

Patch 2a deprecates patch 1a, and it also addresses the issue (and the nit) noted by Knut
The buffer size will now be determined by InputStream.available() given that it returns a
value between 64 and 8192 (8 KB).
Since this code path doesn't appear to be reached currently, I don't expect any changes in
behavior at this point.
The fix is an incremental improvement regardless of the exact values of the limits , as the
existing code would cause Derby to enter an infinite loop if executed.

Patch ready for review.

> Infinite loop in StreamFileContainer.writeColumn
> ------------------------------------------------
>                 Key: DERBY-4519
>                 URL: https://issues.apache.org/jira/browse/DERBY-4519
>             Project: Derby
>          Issue Type: Bug
>          Components: Store
>    Affects Versions:,,,,,,
>            Reporter: Kristian Waagan
>            Assignee: Kristian Waagan
>             Fix For:
>         Attachments: derby-4519-1a-argument_swap.diff, derby-4519-2a-infinite_loop_fixes.diff
> The offset and length argument have been swapped in the calls to InputStream.read(byte,offset,
length) and write(byte,offset, length). This code is inside a do-while (true) loop, and the
only normal way out is when InputStream.read returns -1. This will never happen since the
stream is asked to read zero bytes. Derby ends up eating up all available CPU, limited to
a single core / CPU.
> The bug hasn't been observed because Derby is materializing all values when calling this
code. Enabling streaming capabilities in the sorter revealed it.

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