Update/Select failure when BLOB/CLOB fields updated in several rows by PreparedStatement using setBinaryStream and setCharacterStream

• Key: DERBY-500
• Type: Bug
• Status: Closed
• Resolution: Fixed
• Priority: Major
• Assignee: Sunitha Kambhampati
• Reporter: Peter Kovgan
• Component/s: JDBC
• Affects Version/s: 10.1.1.0
• Fix Version/s: 10.1.2.1, 10.2.1.6

Description

I have table contained BLOB and CLOB fields:

Create table string is:

private static final String CREATE = "CREATE TABLE ta (" +
            "ta_id INTEGER NOT NULL," +
            "mname VARCHAR( 254 ) NOT NULL," +
            "mvalue INT NOT NULL," +
            "mdate DATE NOT NULL," +
            "bytedata BLOB NOT NULL," +
            "chardata CLOB NOT NULL," +
            "PRIMARY KEY ( ta_id ))";


Then I insert 2000 rows in the table.



Then I update all 2000 rows by command:

private static final String UPDATE = "UPDATE ta " +
     "SET bytedata=? ,chardata=? " +
     "WHERE mvalue=?";

/**create blob and clob arrays**/
        int len1 = 10000;//for blob length data
        int len2 = 15000;//for clob length data
        byte buf [] = new byte[len1];
        for(int i=0;i<len1;i++){
         buf [i] = (byte)45;
        }
        ByteArrayInputStream bais = new ByteArrayInputStream(buf);
        
        char[] bufc = new char[len2];
        for (int i = 0; i < bufc.length; i++) {
         bufc[i] = (char)'b';
}
        CharArrayReader car = new CharArrayReader(bufc);
/***/
PreparedStatement pstmt = connection.prepareStatement(UPDATE);
pstmt.setBinaryStream(1,bais, len1);
pstmt.setCharacterStream(2,car, len2);
pstmt.setInt(3,5000);
int updated = pstmt.executeUpdate();
pstmt.close();
System.out.printlen("updated ="+updated );


all 2000 rows updated , because I receive output : updated =2000

But If I run select (SELECT bytedata ,chardata FROM ta) after update, select failed with error:

ERROR XSDA7: Restore of a serializable or SQLData object of class , attempted to
 read more data than was originally stored
        at org.apache.derby.iapi.error.StandardException.newException(StandardEx
ception.java)
        at org.apache.derby.impl.store.raw.data.StoredPage.readRecordFromArray(S
toredPage.java)
        at org.apache.derby.impl.store.raw.data.StoredPage.restoreRecordFromSlot
(StoredPage.java)
        at org.apache.derby.impl.store.raw.data.BasePage.fetchFromSlot(BasePage.
java)
        at org.apache.derby.impl.store.access.conglomerate.GenericScanController
.fetchRows(GenericScanController.java)
        at org.apache.derby.impl.store.access.heap.HeapScan.fetchNextGroup(HeapS
can.java)
        at org.apache.derby.impl.sql.execute.BulkTableScanResultSet.reloadArray(
BulkTableScanResultSet.java)
        at org.apache.derby.impl.sql.execute.BulkTableScanResultSet.getNextRowCo
re(BulkTableScanResultSet.java)
        at org.apache.derby.impl.sql.execute.NestedLoopJoinResultSet.getNextRowC
ore(NestedLoopJoinResultSet.java)
        at org.apache.derby.impl.sql.execute.NestedLoopLeftOuterJoinResultSet.ge
tNextRowCore(NestedLoopLeftOuterJoinResultSet.java)
        at org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.getNextRow
Core(ProjectRestrictResultSet.java)
        at org.apache.derby.impl.sql.execute.SortResultSet.getRowFromResultSet(S
ortResultSet.java)
        at org.apache.derby.impl.sql.execute.SortResultSet.getNextRowFromRS(Sort
ResultSet.java)
        at org.apache.derby.impl.sql.execute.SortResultSet.loadSorter(SortResult
Set.java)
        at org.apache.derby.impl.sql.execute.SortResultSet.openCore(SortResultSe
t.java)
        at org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.open(BasicN
oPutResultSetImpl.java)
        at org.apache.derby.impl.sql.GenericPreparedStatement.execute(GenericPre
paredStatement.java)
        at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(EmbedState
ment.java)
        at org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(Em
bedPreparedStatement.java)
        at org.apache.derby.impl.jdbc.EmbedPreparedStatement.execute(EmbedPrepar
edStatement.java)
        at com.beep_beep.dbtest.complex.Benchmark.testSelect(Unknown Source)
        at com.beep_beep.dbtest.complex.Benchmark.executeSimplestBigTable(Unknown Sour
ce)
        at com.beep_beep.dbtest.complex.Benchmark.testBigTable(Unknown Source)
        at com.beep_beep.dbtest.complex.Benchmark.executeDegradationBenchmark(Unknown
Source)
        at com.beep_beep.dbtest.complex.Benchmark.main(Unknown Source)


From the stack trace and from console I see that Update passed, but error was raised in Select after Update.


When I try the same update, but with difference(I changed WHERE clause, causing update only 1 row):
private static final String UPDATE = "UPDATE ta " +
     "SET bytedata=? ,chardata=? " +
     "WHERE mname=?";

PreparedStatement pstmt = connection.prepareStatement(UPDATE);
pstmt.setBinaryStream(1,bais, len1);
pstmt.setCharacterStream(2,car, len2);
pstmt.setInt(3,"PETER");
int updated = pstmt.executeUpdate();
pstmt.close();
System.out.printlen("updated ="+updated );

Only 1 row updated , because I receive output : updated =1

In this case I have NO errors in select(the same as previous) .

My assumption:
It seems that Update receives ByteArrayInputStream and updates correctly only 1 row, then all rows updated by some
incorrect value(may be because ByteArrayInputStream reached its end in first update), causing select failure.

I tested PointBase by the same test and PointBase passed this stage without errors, no matter how many rows was updated.
So I think it is a bug.

Thank you.

Comments

[Peter Kovgan]

In previous description I have one mistake:

instead pstmt.setInt(3,"PETER");
really in code I have pstmt.setString(3,"PETER");

[Peter Kovgan]

Could you provide some example how to Update BLOB and CLOB fields correctly ?

[A B]

Unassigning myself since I'm not currently looking at this issue and Sunitha is looking into it...

[Sunitha Kambhampati]

Background :
In Derby, when a stream is set as a parameter value, the wrapper stream object used for character data is ReaderToUTF8Stream
and for binary data it is RawToBinaryFormatStream.Both these stream objects on read() return data in a format that is used to store the respective datatype value. E.g in case of char, the characters read from the user stream are converted using utf-8 derby specific encoding and read calls return
the data as expected by store layer. Beginning 2 bytes either have the utflen or has zeroes, or if it is a long string, then the value is ended with the special marker 0xE0 , 0x00, 0x00. For binary data, the stream data is prepended with 4 zeroes.

Problem:
once,the stream has been read fully and end of file reached, further read() returns a -1. If a stream is re-read, it returns a -1 which is incorrect data. E.g.in the repro for DERBY-500, the update statement has multiple rows that qualify and since the stream parameter is used; the first row gets updated with the correct value and the stream is drained. For the subsequent rows, the read from the stream parameter value returns -1 and thus is updated with incorrect data.When retrieving the row back, the format of the fields is incorrect and thus the exception.
__________
This patch

1. adds changes to RawToBinaryFormatStream and ReaderToUTF8Stream to throw an EOFException if stream is re-read.
If a stream value has been fully read and end of file reached, any further reads on the stream object will result in an EOFException. This seems reasonable and more correct than using incorrect values.
Adds a new error message - 'Stream has already been read and end-of-file reached and cannot be re-used.'

2. changes to RememberBytesInputStream to keep track of the stream state and not call read on the stream objects once eof is reached.

3. Fix a bug in StoredPage.logColumn related to streams. In one particular scenario, column was not being set to RememberBytesInputStream object and thus losing the data that would be read from stream into RememberBytesInputStream.

4. adds testcases to store/streamingColumn.java and lang/forbitdata.java


Also note
- This fix affects cases when a stream is re-used in which case an exception will be thrown.
So code that reads the stream once and materializes it will not be affected. E.g. Currently in case of char,varchar,long varchar, streams are materialized and this will work fine as before.


Ran tests ok on jdk142/win2k (using classes directory)

svn stat
M java\engine\org\apache\derby\impl\jdbc\RawToBinaryFormatStream.java
M java\engine\org\apache\derby\impl\jdbc\ReaderToUTF8Stream.java
M java\engine\org\apache\derby\impl\store\raw\data\RememberBytesInputStream.java
M java\engine\org\apache\derby\impl\store\raw\data\StoredPage.java
M java\engine\org\apache\derby\iapi\reference\SQLState.java
M java\engine\org\apache\derby\loc\messages_en.properties
M java\testing\org\apache\derbyTesting\functionTests\tests\lang\forbitdata.java
M java\testing\org\apache\derbyTesting\functionTests\tests\store\streamingColumn.java
M java\testing\org\apache\derbyTesting\functionTests\master\streamingColumn.out
M java\testing\org\apache\derbyTesting\functionTests\master\forbitdata.out

I'll add clarifications to the paper - JDBCImplementation.html and attach it as another patch to this jira entry.

Can someone please review it. Thanks.

[Sunitha Kambhampati]

I would like this fix to go into 10.1 codeline.

DERBY-500 fix was committed to trunk(10.2) with SVN 326307. The SVN merge command has conflicts in 2 files ( ReaderToUTF8Stream and streamingColumn.java). The reason for this is some changes went into these 2 files as part of DERBY352, but fix for DERBY352 is not a bug-fix but a behavior change and so it is not ported to 10.1 codeline. As a result, I have had to hand merge these 2 files and so I am attaching the patch ( V10.1_Derby500.diff.txt and V10.1_Derby500.stat.txt).

This patch fixes DERBY500 in 10.1 codeline, similar to trunk. Also have added comments in ReaderToUTF8Stream.close() to explain why reader.close() should not be called.

I ran derbyall on ibm 142/win2k and there were 4 failures , none related to my change.
derbyall/derbyall.fail:i18n/JapanCodeConversion.sql
derbyall/derbyall.fail:i18n/iepnegativetests_ES.sql
derbyall/derbynetclientmats/derbynetmats.fail:tools/importExport.java
derbyall/derbynetmats/derbynetmats.fail:tools/importExport.java

First two are master updates issue (not related to this change). Rerunning the 2 importExport tests in network server frameworks and running derbynetclientmats and derbynetmats does not have any failures.

If someone could review and commit it, that would be great. Thanks.

[Kathey Marsden]

Checked this fix into 10.1

Date: Thu Oct 20 15:18:36 2005
New Revision: 327012

URL: http://svn.apache.org/viewcvs?rev=327012&view=rev

[Sunitha Kambhampati]

committed to
10.2 - SVN 326307
10.1.2 - SVN 327012

I have verified the fix by running a test.

[Sunitha Kambhampati]

This patch(Doc_JdbcImpl_paper.diff.txt) adds some clarifications to the JDBCImplementation.html paper.
I used vi to edit this file. Can someone please review and commit this. Thanks.

[Jean T. Anderson]

Committed Doc_JdbcImpl_paper.diff.txt, revision 331887.

[Sunitha Kambhampati]

Thanks Jean for commiting the clarifications to JDBCImplementation.html that I wanted to target with DERBY500. Code fixes have already been committed and resolved, hence closing the bug.