[ 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.
