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https://issues.apache.org/jira/browse/DERBY-2646?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kristian Waagan updated DERBY-2646:
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Attachment: derby-2646-02a-clob-reorg.diff
derby-2646-02a-clob-reorg.diff
'derby-2646-02a-clob-reorg.diff' is a stab at reorganizing the upper level Clob
code in the embedded driver.
I have run suites.All without failures.
Please note that the patch, although operational, is preliminary. I'm sorry it
became so big, but I think it will be hard to split it up into smaller parts.
I'm also very short on time, but I still feel this is worth getting done for
10.3.
For now I'm primarily interested in design feedback, but other kinds of
feedback (bugs, suggestions etc) are welcome too.
Although I plan to address more cleanup and bugs in later patches, a few fixes
were incorporated into the 2a patch. For instance, ClobTest has 3
failures/errors when run against trunk, but none when run with the patch.
Comments on the patch:
a) EmbedClob now works against the new interface InternalClob
b) There are two different kinds of internal Clob representations;
StoreStreamClob (which is read-only) and ClobStreamControl (which I might
rename, name suggestions? TemporaryClob?). If you fetch an existing Clob from
the database, you start out with a StoreStreamClob. If you modify it, the Clob
content is copied into ClobStreamControl. The switch is done in EmbedClob.
c) I need to look into exception handling. For various reasons it seems many
methods must throw SQLExceptions. StoreStreamControl tends to get
StandardException from store, ClobStreamControl tends to get
StandardException/SQLException from LOBStreamControl. And of course IOException
is well represented.
d) I need to look into/verify synchronization (on the connection child). Can
anyone please enlighten me on the importance of calling
setupContextStack/restoreContextStack?
e) All character positions in InternalClob are 1-based. Byte positions are
0-based.
f) Positioning streams at character positions are done by reading the byte
stream from position 0 and counting characters. This implies UTF-8 decoding.
Changing this will not happen in this patch/issue. Different improvements might
be suitable for the store streams and the temporary Clobs (i.e. caching
positions or changing to UTF-16).
My apologies for bringing a rather big change to the community this close to
the freeze date. However, unless I get serious pushback, I will drive this
forward to completion for 10.3.
> Cleanup of Clob control/support structures
> ------------------------------------------
>
> Key: DERBY-2646
> URL: https://issues.apache.org/jira/browse/DERBY-2646
> Project: Derby
> Issue Type: Sub-task
> Components: JDBC
> Affects Versions: 10.3.0.0
> Reporter: Kristian Waagan
> Assigned To: Kristian Waagan
> Attachments: derby-2646-01a_trailing_space.diff,
> derby-2646-01a_trailing_space.stat, derby-2646-02a-clob-reorg.diff,
> derby-2646-02a-clob-reorg.diff
>
>
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