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https://issues.apache.org/jira/browse/DERBY-6000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13574333#comment-13574333
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Kristian Waagan commented on DERBY-6000:
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> I'll ask Lance if he has any advice about what this method should return on
> Derby.
> Seems to me there are at least 2 theories about this:
>
> o 4294967294 - The maximum number of bytes which an in-memory CLOB can
> consume.
> This is misleading for people interested in the maximum number of bytes
> which can be stored in the database.
>
> o 2147483647 - The maximum number of bytes in a LOB stored in the database.
> This is misleading for people who are interested in the memory
> representation.
My take on this is that people would use this method to figure out how big LOBs
they can store in the database. I don't think they care about representation
(i.e. on-disk vs in-memory). This gives rise to two questions:
a) How many bytes can I stuff into a single BLOB?
b) How many characters can I stuff into a single CLOB?
I hope the above is the intention of the method - I fail to immediately see any
other meaningful uses of it.
The answers to (a) and (b) may be different for some databases, for instance
because the DBMS has an internal limitation on how many bytes it can
store/handle. Combined with the fact that one character doesn't always equal
one byte, that could make the maximum size of a CLOB data dependent (i.e.
storing English vs Chinese text).
> Implement support for JDBC 4.2
> ------------------------------
>
> Key: DERBY-6000
> URL: https://issues.apache.org/jira/browse/DERBY-6000
> Project: Derby
> Issue Type: Improvement
> Components: JDBC
> Reporter: Rick Hillegas
> Attachments: derby-6000-01-aa-executeLargeUpdateEmbedded.diff,
> derby-6000-02-ad-executeLargeUpdateClient.diff,
> derby-6000-03-aa-executeLargeBatch.diff,
> derby-6000-04-aa-setLargeMaxRows.diff,
> derby-6000-05-aa-executeLargeUpdatePS.diff,
> derby-6000-06-aa-DatabaseMetaData.diff,
> derby-6000-07-ab-batchUpdateException.diff,
> derby-6000-08-aa-batchUpdateExceptionConstructor.diff,
> derby-6000-09-ac-setObjectPS.diff,
> derby-6000-10-aa-rename_getMaxLogicalLobSize.diff, JDBC_4.2_Changes.html
>
>
> Open JDK 8 will include maintenance rev 4.2 of JDBC. The public discussion of
> JDBC 4.2 will take place here: http://openjdk.java.net/jeps/170. We will want
> to build Derby support for JDBC 4.2 after a public spec appears. At this
> time, it is unclear what Derby release will carry this support.
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