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https://issues.apache.org/jira/browse/DERBY-3781?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kristian Waagan updated DERBY-3781:
-----------------------------------

    Fix Version/s: 10.5.0.0

Committed 'derby-3781-1a-fix_and_test.diff' to trunk with revision 677172.

> PositionedStoreStream.reposition(pos) with pos greater than length leaves the 
> stream object in an inconsistent state
> --------------------------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-3781
>                 URL: https://issues.apache.org/jira/browse/DERBY-3781
>             Project: Derby
>          Issue Type: Bug
>          Components: Store
>    Affects Versions: 10.3.3.0, 10.4.1.3, 10.5.0.0
>            Reporter: Kristian Waagan
>            Assignee: Kristian Waagan
>            Priority: Minor
>             Fix For: 10.5.0.0
>
>         Attachments: derby-3781-1a-fix_and_test.diff
>
>
> PositionedStoreStream.reposition(pos) with pos greater than the stream length 
> leaves the stream object in an inconsistent state, causing subsequent calls 
> to fail or the state to remain inconsistent (which can cause the wrong data 
> to be returned).
> The problem is that the position variable gets out of sync with the 
> underlying stream.
> There are at least two ways to fix this (assuming the positioned store stream 
> does not know the length of the underlying stream):
>  a) Reset stream to position zero.
>  b) Let the stream be positioned at EOF and update the internal position 
> variable.
> Option b) leaves the stream in an unusable state, and the next request will 
> cause option a) to be performed. It also require a slight rewrite of 
> 'PositionedStoreStream.skipFully' and 'PositionedStoreStream.reposition' to 
> be able to determine the position of the stream (the length in this case).
> Option a) will cause the first page of the stream to be read into the cache 
> (if not already there), but taken the reason for doing this is an error 
> condition it seems acceptable.
> A correct value of the position variable is required for correct/valid 
> operation of PositionedStoreStream.

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