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From "Mike Matrigali (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DERBY-6214) PreparedStatement.setObject(int, Object, Types.CLOB) fail with DerbyNet
Date Fri, 24 May 2013 21:19:21 GMT

    [ https://issues.apache.org/jira/browse/DERBY-6214?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13666688#comment-13666688
] 

Mike Matrigali commented on DERBY-6214:
---------------------------------------

so comparing embedded to client/server is likely not very useful in the setObject and setString
case.  In embedded we have the actual string so there
is no stream, so nothing to get closed after draining, so no problem.  In client/server we
are going to send a stream over and we are not going to know
if it is small or big so we probably can't just create an object in memory to "back" up the
stream on the server side.

I might suggest looking at embedded in one of the setStream cases with a stream larger than
32k, and see if it works for an update of more than one row.  If it
does it might lead to existing mechanism to save off a stream so that it can be reopened.
 I believe there are existing holder objects that will take a stream and
buffer it to disk if need be so that you can read it again.  

One thing I don't know is if it should be the job of server side client/server code that you
are looking at to do this, of if it should be the job of sql execution engine
to recognize an input clob/blob/stream can't be read twice and it should do this work in the
case of an update that might require updating more than one row.
I think we use to have generic embedded issues with blob/clob where it would instantiate them
into memory in cases like this.  I thought those had been resolved,
but maybe this is a case that slipped through.    Should be clear if you follow the code for
an embedded update of clob where user provides a stream.
                
> PreparedStatement.setObject(int, Object, Types.CLOB) fail with DerbyNet
> -----------------------------------------------------------------------
>
>                 Key: DERBY-6214
>                 URL: https://issues.apache.org/jira/browse/DERBY-6214
>             Project: Derby
>          Issue Type: Bug
>    Affects Versions: 10.8.3.0, 10.9.1.0
>            Reporter: Rong Qu
>            Assignee: Mamta A. Satoor
>         Attachments: Derby6214.java, Derby6214_setup.sql, Derby6214_ver2.java, derby.log,
DerbyNet_client_test.sql
>
>
> The issue is specific to the DerbyNet client driver, and doesn't seem to occur using
embedded Derby.
>  "PreparedStatement.setObject(int, Object, Types.CLOB)". It seems to be a problem updating
a CLOB column with a parameterized value using the DerbyNet client driver, and if the update
SQL ends up updating more than one row. I attached a simple test case that just uses JDBC
to reproduce the error. The exception looks like this:
> org.apache.derby.client.am.BatchUpdateException: Non-atomic batch failure.  The batch
was submitted, but at least one exception occurred on an individual member of the batch. Use
getNextException() to retrieve the exceptions for specific batched elements.
>     at org.apache.derby.client.am.Agent.endBatchedReadChain(Unknown Source)
>     at org.apache.derby.client.am.PreparedStatement.executeBatchRequestX(Unknown Source)
>     at org.apache.derby.client.am.PreparedStatement.executeBatchX(Unknown Source)
>     at org.apache.derby.client.am.PreparedStatement.executeBatch(Unknown Source)
>     ...
> Caused by: org.apache.derby.client.am.SqlException: Error for batch element #0: An unexpected
exception was thrown
>     at org.apache.derby.client.am.Statement.completeExecute(Unknown Source)
>     at org.apache.derby.client.net.NetStatementReply.parseEXCSQLSTTreply(Unknown Source)
>     at org.apache.derby.client.net.NetStatementReply.readExecute(Unknown Source)
>     at org.apache.derby.client.net.StatementReply.readExecute(Unknown Source)
>     at org.apache.derby.client.net.NetPreparedStatement.readExecute_(Unknown Source)
>     at org.apache.derby.client.am.PreparedStatement.readExecute(Unknown Source)
>     ... 4 more
> Caused by: org.apache.derby.client.am.SqlException: Error for batch element #0: Java
exception: 'Stream has already been read and end-of-file reached and cannot be re-used.: java.io.EOFException'.
>     at org.apache.derby.client.am.SqlException.<init>(Unknown Source)
>     at org.apache.derby.client.am.SqlException.<init>(Unknown Source)
>     ... 10 more

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