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From "Mamta A. Satoor (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-4805) Increase the length of the RDBNAM field in the DRDA implementation
Date Mon, 13 Jan 2014 22:11:54 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4805?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13870057#comment-13870057
] 

Mamta A. Satoor commented on DERBY-4805:
----------------------------------------

Here is the brief explanation of code around the NPE. The NPE related code is for backward
compatibility. Basically, what we are trying to do here is if the 10.11 client is talking
to a server with version 10.10 and under, then we do not want to allow the new RDBNAM limit
of 1024 bytes. We check for server version by looking at database meta data. But, at this
point in the code, the client is just getting ready to send connection request to the server
and has not established a communication with the server yet. Because of this, the client does
not have access to database meta data and hence we can not determine the server version. The
NPE results from an attempt to access database meta data's version info when the meta data
object has not yet been initialized. Any ideas on how we can decide the correct RDBNAM length
for 10.11 client when talking to different versions of the server?


> Increase the length of the RDBNAM field in the DRDA implementation
> ------------------------------------------------------------------
>
>                 Key: DERBY-4805
>                 URL: https://issues.apache.org/jira/browse/DERBY-4805
>             Project: Derby
>          Issue Type: Improvement
>          Components: Network Client, Network Server
>    Affects Versions: 10.7.1.1
>            Reporter: Tiago R. Espinha
>            Assignee: Mamta A. Satoor
>              Labels: derby_triage10_9
>         Attachments: DERBY4805_patch2_diff.txt, DERBY4805_patch2_stat.txt, DERBY_4805_diff_patch1.txt
>
>
> Currently, whenever the client driver is used, there is a limit of 255 bytes for the
database name. This is defined by the DRDA spec and there has been a discussion on the list
[1]/[2] as to whether this limit should be raised due to the introduction of the new ACR that
allows for UTF-8 characters.
> UTF-8 characters can take up to four bytes and this reduces the limit in characters dramatically.
> This should be an easy change as there is a codepoint that defines this limit.
> [1] did not work but [2] did
> [1] - http://old.nabble.com/Database-name-length-tt29691419.html
> [2]http://apache-database.10148.n7.nabble.com/Database-name-length-td33182.html



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