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https://issues.apache.org/jira/browse/DERBY-6214?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13685889#comment-13685889
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Mamta A. Satoor commented on DERBY-6214:
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Just to recap, in this jira, we are trying to fix
PreparedStatement.setObject(int, Object, Types.CLOB) when Object is of type
String and that String object is less than or equal to 10922 characters. The 2
attached patches attempt to fix the problem by sending such Strings as String
on the wire from client to server rather than stream(this matches the behavior
for PreparedStatement.setString). If we decide to do the same for
ResultSet.updateObject (since the code is shared by ResultSet.updateObject and
PreparedStatement.setObject), it runs into following exception
.derbyTesting.functionTests.tests.jdbcapi.ParameterMappingTest)java.lang.ClassCastException:
java.lang.String incompatible with java.sql.Clob
at
org.apache.derby.client.net.NetStatementRequest.computeProtocolTypesAndLengths(NetStatementRequest.java:1462)
at
org.apache.derby.client.net.NetStatementRequest.buildSQLDTAcommandData(NetStatementRequest.java:545)
at
org.apache.derby.client.net.NetStatementRequest.writeExecute(NetStatementRequest.java:162)
at
org.apache.derby.client.net.NetPreparedStatement.writeExecute_(NetPreparedStatement.java:156)
at
org.apache.derby.client.am.ClientResultSet.writeUpdateRow(ClientResultSet.java:4357)
at
org.apache.derby.client.am.ClientResultSet.positionToCurrentRowAndUpdate(ClientResultSet.java:4098)
at
org.apache.derby.client.am.ClientResultSet.updateRowX(ClientResultSet.java:3651)
at
org.apache.derby.client.am.ClientResultSet.updateRow(ClientResultSet.java:3555)
at
org.apache.derbyTesting.functionTests.tests.jdbcapi.ParameterMappingTest.testDerby6214updateXXX(ParameterMappingTest.java:439)
I have been looking at this exception and it looks like when dealing with
ResultSet.updateObject on a CLOB column, we have coded everywhere to look for
Clob column. I tried changing the offending code line in the stack trace above
and ran into same exception again at a different part of the code as shown below
java.lang.ClassCastException: java.lang.String incompatible with java.sql.Clob
at
org.apache.derby.client.net.NetStatementRequest.buildEXTDTA(NetStatementRequest.java:1050)
at
org.apache.derby.client.net.NetStatementRequest.writeExecute(NetStatementRequest.java:168)
at
org.apache.derby.client.net.NetPreparedStatement.writeExecute_(NetPreparedStatement.java:156)
at
org.apache.derby.client.am.ClientResultSet.writeUpdateRow(ClientResultSet.java:4368)
at
org.apache.derby.client.am.ClientResultSet.positionToCurrentRowAndUpdate(ClientResultSet.java:4109)
at
org.apache.derby.client.am.ClientResultSet.updateRowX(ClientResultSet.java:3662)
at
org.apache.derby.client.am.ClientResultSet.updateRow(ClientResultSet.java:3566)
at
org.apache.derbyTesting.functionTests.tests.jdbcapi.ParameterMappingTest.testDerby6214updateXXX(ParameterMappingTest.java:439)
Fixing that by to accomodate String rather than Clob at this place resulted in
same exception in another place. So I do not think we can avoid using a Clob
object for ResultSet.updateObject for a CLOB column easily. I am looking at
intercepting the String object from CrossConverts.setObject for
ResultSet.updateObject and see if we can fix the problem that way rather than
having a special case in highly reused code in CrossConverts.setObject.
Additionally, I put println in CrossConverts.setObject where we see if we are
dealing with a String less than or equal to 10922 characters for a CLOB object
and ran existing junit and derbyall tests and found that this code gets called
only by ParameterMappingTest(by the new junit test that I have added in my
codeline) and by existing junit test in UpdatableResultSetTest. So, atleast
from the test runs, it looks like the suggested code changes in the 2 patches
are used only by ResultSet.updateObject and PreparedStatement.setObject
> 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_patch1_diff.txt,
> DERBY6214_patch1_stat.txt, DERBY6214_patch2_diff.txt, 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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