Apache Derby 10.3.3.0 Release

If you are currently using Derby 10.3.1.4 or Derby 10.3.2.1, it is strongly
recommended that you upgrade to Derby 10.4.1.3 or 10.3.3.0 to avoid
any chance of database corruption due to an issue with multiple threads
accessing a database that is documented in DERBY-3347.

This bug can cause unrecoverable database corruption during periods of
heavy, multi-thread I/O operations. The error produced in the test case
used to diagnose the problem was:

ERROR XSDB3: Container information cannot change once written: was 0, now 80.

It is felt that other errors might also be generated when this type of
corruption occurs. The corruption message will most likely refer to page 0
of the container. For example:

ERROR XSDG1: Page Page(0 ,Container(0, 5856)) could not be
written...

This bug corrupts the pages on disk and can go unnoticed. If you do not
run database consistency checks regularly it is recommended you begin doing
so as soon as possible after the upgrade. To insure that corruption has not
already occurred in existing databases, after upgrade run the database
consistency check at least once to validate all tables in the database. This
process is documented at:

http://wiki.apache.org/db-derby/DatabaseConsistencyCheck

If the corruption has already occurred there is no guaranteed recovery of data
other than to recover from the last good backup. When doing so one should
also check that the previous backup did not also have the corruption.

In some cases one may recover data from the existing
database, depending on the extent of the corruption, but will require
by hand data recovery. Depending on the type of corruption this may
be successful or not. one should consult the Derby list if attempting
this recovery - no automatic software solution to this recovery exists.

Version 10.3.3.0 can be downloaded from:
http://db.apache.org/derby/releases/release-10.3.3.0.cgi

Version 10.4.1.3 can be downloaded from:
http://db.apache.org/derby/releases/release-10.4.1.3.cgi

For help or questions, please post to the Derby User list.
For instructions on how to subcribe and post to the Derby User list,
please see:

http://db.apache.org/derby/derby_mail.html

Use the links below to download a distribution of Apache Derby from one of our mirrors. You should always verify the integrity of distribution files downloaded from a mirror.

There are four different distributions:

• bin distribution - contains the documentation, javadoc, and jar files for Derby.
• lib distribution - contains only the jar files for Derby.
• lib-debug distribution - contains jar files for Derby with source line numbers.
• src distribution - contains the Derby source tree at the point which the binaries were built.

db-derby-10.3.3.0-bin.zip [PGP] [MD5]
db-derby-10.3.3.0-bin.tar.gz [PGP] [MD5]

db-derby-10.3.3.0-lib.zip [PGP] [MD5]
db-derby-10.3.3.0-lib.tar.gz [PGP] [MD5]

db-derby-10.3.3.0-lib-debug.zip [PGP] [MD5]
db-derby-10.3.3.0-lib-debug.tar.gz [PGP] [MD5]

db-derby-10.3.3.0-src.zip [PGP] [MD5]
db-derby-10.3.3.0-src.tar.gz [PGP] [MD5] (Note that, due to long filenames, you will need gnu tar to unravel this tarball.)

There are two separate Eclipse plugins for Derby:

• derby_core_plugin - provides the Derby jar files to other plugins in Eclipse.
• derby_ui_plugin - provides an Apache Derby Nature in Eclipse for easy database application development.

derby_core_plugin_10.3.3.652961.zip [PGP] [MD5]
derby_ui_plugin_1.1.1.zip [PGP] [MD5]

Please note: both plugins must be installed for full functionality. For information on installing and using the Derby plugins for Eclipse, please see the Using the 10 Core and 1.1 UI Derby plug-ins page.

These notes describe the difference between Derby release 10.3.3.0 and the preceding release 10.3.2.1.

• Overview
• Bug Fixes
• Issues
• Build Environment

Overview

Derby is a pure Java relational database engine using standard SQL and JDBC as its APIs.

Derby functionality includes:

• Embedded engine with JDBC drivers
• Network Server
• Network client JDBC drivers
• Command line tools: ij (SQL scripting), dblook (schema dump) and sysinfo (system info)

Issues

The following issues are addressed by Derby release 10.3.3.0. These issues are not addressed in the preceding 10.3.2.1 release.

Compared with the previous release (10.3.2.1), Derby release 10.3.3.0 introduces the following new important fixes. These merit your special attention.

• Note for DERBY-3347: A bug that could cause unrecoverable database corruption has been fixed.

• Note for DERBY-3301: Queries with nested EXIST, ANY or IN clauses now return correct results.

• Note for DERBY-2351: An ORDER BY clause of a DISTINCT query which specifies to order by a column which was not in the DISTINCT list is now rejected, because the intent of the query is ambiguous. Previously, Derby instead produced non-distinct results. Also, an ORDER BY clause which specifies a table-name-qualified column alias is now rejected as invalid, where previously it was accepted.

Note for DERBY-3347

Summary of Change

A bug that could cause unrecoverable database corruption has been fixed.

Symptoms Seen by Applications Affected by Change

A bug that could cause database corruption was introduced in the 10.3 codeline and affects the following releases:

• Apache Derby 10.3.1.4
• Apache Derby 10.3.2.1

Users who are hit by this bug may experience exceptions at various times during execution of SQL statements, booting or shutdown of a database, or during checkpointing. It may result in a number of different error messages, including any of these:

ERROR XSDB3: Container information cannot change once written: was 0, now 80
ERROR XSDG1: Page Page(1039,Container(0, 5856)) could not be written to disk, please check if disk is full.
ERROR XSDG2: Invalid checksum on Page Page(0,Container(0, 1313))
ERROR XSDG3: Meta-data for Container org.apache.derby.impl.store.raw.data.RAFContainer4@1afb0c7 could not be accessed
ERROR XSLA1: Log Record has been sent to the stream, but it cannot be applied to the store (Object null). This may cause recovery problems also.

Incompatibilities with Previous Release

None.

Rationale for Change

Database corruption is bad.

Application Changes Required

No changes are required. However, since the database corruption may go unnoticed for a while, users may want to check the consistency of their databases after upgrading Derby. The process is described on the following wiki page: http://wiki.apache.org/db-derby/DatabaseConsistencyCheck . If a corruption is detected, restoring the database from backup is the only reliable way to recover.

Note for DERBY-3301

Summary of Change

Queries with nested EXIST, ANY or IN clauses now return correct results.

Symptoms Seen by Applications Affected by Change

In the previous release, applications that executed SQL statements containing nested EXISTS, ANY or IN clauses could see fewer rows than those satisfying the query. In particular, rows that had the same value for one of the selected columns as another row might not have been returned.

Incompatibilities with Previous Release

None.

Rationale for Change

The previous behavior violated the ANSI SQL standard. The new behavior is correct.

Application Changes Required

Typically none, but applications must handle that the correct results are now returned.

Note for DERBY-2351

Summary of Change

An ORDER BY clause of a DISTINCT query which specifies to order by a column which was not in the DISTINCT list is now rejected, because the intent of the query is ambiguous. Previously, Derby instead produced non-distinct results. Also, an ORDER BY clause which specifies a table-name-qualified column alias is now rejected as invalid, where previously it was accepted.

Symptoms Seen by Applications Affected by Change

New rules for DISTINCT and ORDER BY

Applications which specify certain combinations of SELECT DISTINCT with ORDER BY will now receive an error message, whereas formerly such applications received non-distinct results.

As an example, take the following:

create table person (name varchar(10), age int);
insert into person values ('John', 10);
insert into person values ('John', 30);
insert into person values ('Mary', 20);

SELECT DISTINCT name FROM person ORDER BY age;

The query above is now rejected, with the error message:

If the AGE column is included in the DISTINCT list in the above query, there is no ambiguity

New column alias rules

Applications which specify a column alias for a column in the SELECT statement, and which specify an ORDER BY clause which specifies that column alias qualified by the table name, will now receive an error indicating that the ORDER BY clause is invalid.

As an example, take the following:

create table t1 (i int, j int);
select t1.id as idcolumn1, t1.id as idcolumn2 from t1 order by t1.idcolumn1, t1.idcolumn2;

This query is now rejected, as there is no column named 'idcolumn1' in table 't1'. The error message is:

Valid forms of the query above are:

select t1.id as idcolumn1, t1.id as idcolumn2 from t1 order by idcolumn1, idcolumn2;

or

select t1.id as idcolumn1, t1.id as idcolumn2 from t1 order by t1.id, t1.id;

Rationale for Change

When the query ambiguously specifies both DISTINCT and ORDER BY, Derby was unsure whether to return the rows properly ordered, but non-distinct, or to return a distinct set of rows, but in an unknown order. Since no clear resolution of the ambiguity could be found, we chose instead to reject the query.

The rules for resolving column references in ORDER BY clauses have been enhanced to consider column aliases and column names more fully. Derby now uses different resolution rules depending on whether the ORDER BY column reference is table.column, or just column:

• if the table name is provided, we match against the underlying table name, and don't consider any aliases
• if the table name is NOT provided, we first match against the alias name, if present, and if no alias name matches then we match against the underlying source column name.

Application Changes Required

A query which specifies ordering by a non-distinct column should instead include the ORDER BY column in the DISTINCT list, to resolve the ambiguity about which values of that column should be used to distinctly identify the resulting rows.

A query which specifies table-name.alias-name should be rewritten to specify either simply alias-name, or table-name.column-name.

Build Environment

Derby release 10.3.3.0 was built using the following environment:

• Branch - Source code came from the 10.3 branch.
• Machine - Cygwin on Microsoft Windows XP Professional Version 2002 Service Pack 2.
• Ant - Apache Ant version 1.7.0 compiled on December 13 2006.
• JDK 1.4 - Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_07-b05)
• Java 6 - Java(TM) SE Runtime Environment (build 1.6.0_01-b06).
• OSGi - osgi.jar was used to build org.apache.derby.osgi.EmbeddedActivator.
• Compiler - The 1.4.2_07-b05 javac was used to compile all classes except for the JDBC4 drivers. The JDBC4 driver classes were compiled using the 1.6.0_01-b06 javac.
• JSR 169 - Java ME support was built using Java ME CDC/Foundation Specification 1.1 libraries from IBM WebSphere Everyplace Micro Environment 6.1

It is essential that you verify the integrity of the downloaded files using the PGP and MD5 signatures. MD5 verification ensures the file was not corrupted during the download process. PGP verification ensures that the file came from a certain person.

The PGP signatures can be verified using PGP or GPG. First download the Apache Derby KEYS as well as the asc signature file for the particular distribution. It is important that you get these files from the ultimate trusted source - the main ASF distribution site, rather than from a mirror. Then verify the signatures using ...

% pgpk -a KEYS
% pgpv db-derby-X.Y.tar.gz.asc

or

% pgp -ka KEYS
% pgp db-derby-X.Y.tar.gz.asc

or

% gpg --import KEYS
% gpg --verify db-derby-X.Y.tar.gz.asc

To verify the MD5 signature on the files, you need to use a program called md5 or md5sum, which is included in many unix distributions. It is also available as part of GNU Textutils. Windows users can get binary md5 programs from here, here, or here.

We strongly recommend you verify your downloads with both PGP and MD5.