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http://issues.apache.org/jira/browse/DERBY-1471?page=comments#action_12458092 ]
Knut Anders Hatlen commented on DERBY-1471:
-------------------------------------------
I have tested the lengthless versions of PreparedStatement.setClob(),
PreparedStatement.setCharacterStream(), PreparedStatement.setAsciiStream(),
PreparedStatement.setBlob(), PreparedStatement.setBinaryStream(),
ResultSet.updateClob(), ResultSet.updateCharacterStream(),
ResultSet.updateAsciiStream(), ResultSet.updateBlob() and
ResultSet.updateBinaryStream(), and they all seem to work without throwing
OutOfMemoryError for large lobs. Great! :)
However, compatibility with older servers seems to have been broken. When I try
to stream a lob (small enough to fit in the client's memory) to a 10.2.1.6
server, I get a protocol error: "java.sql.SQLException: A network protocol
error was encountered and the connection has been terminated: A PROTOCOL Data
Stream Syntax Error was detected. Reason: 0x0." I think we need to check the
version of the server before using layer b streaming. This could be done in
NetDatabaseMetaData.computeFeatureSet_().
Thank you for addressing my previous comments. My comment about
readAndSetExtParam() was a bit unclear. What I meant, was that the if-clause
could be written as
if (stream == null) {
// same code as before for null
} else if (stream instanceof LayerBStreamedEXTDTAReaderInputStream) {
// new Layer B code
} else {
// same code as in the old else-clause
}
The main point is that we should have an "else" clause at the end which catches
all cases, instead of only having "if" and "else if" clauses. I think that it
will make the code clearer, since a reader doesn't have to figure out whether
there are cases that don't match any of the if/else-if clauses.
> Implement layer B streaming for new methods defined in JDBC4.0
> --------------------------------------------------------------
>
> Key: DERBY-1471
> URL: http://issues.apache.org/jira/browse/DERBY-1471
> Project: Derby
> Issue Type: New Feature
> Components: Network Client
> Reporter: Tomohito Nakayama
> Assigned To: Tomohito Nakayama
> Attachments: DERBY-1471.diff, DERBY-1471.patch, DERBY-1471.stat,
> DERBY-1471_2.patch, DERBY-1471_2.stat, DERBY-1471_3.patch, DERBY-1471_3.stat,
> DERBY-1471_4.patch, DERBY-1471_4.stat
>
>
> JDBC 4.0 introduced new methods which take parameters for object to be sent
> to sever without length information.
> For those methods, Layer B streaming is best way to implement sending object
> to server.
> This issue is representation of DERBY-1417 in Network Client.
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