[ http://issues.apache.org/jira/browse/DERBY-500?page=all ]
Sunitha Kambhampati updated DERBY-500:
--------------------------------------
Attachment: Derby500.diff.txt
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.
> Update/Select failure when BLOB/CLOB fields updated in several rows by
> PreparedStatement using setBinaryStream and setCharacterStream
> -------------------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-500
> URL: http://issues.apache.org/jira/browse/DERBY-500
> Project: Derby
> Type: Bug
> Components: JDBC
> Versions: 10.1.1.0
> Environment: Windows 2000, java SDK 1.4
> Reporter: Peter Kovgan
> Assignee: Sunitha Kambhampati
> Fix For: 10.1.2.0
> Attachments: Derby500.diff.txt, Derby500.stat.txt
>
> 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.
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see:
http://www.atlassian.com/software/jira
