</li><li>If a Reader or InputStream of a LOB is not closed, the LOB can not be deleted (embedded mode only).
The exception is typically 'Error while renaming file'). As a workaround, set the system property
'h2.lobCloseBetweenReads' to true to close the LOB files between read operations.
However this slows down reading.
</li><li>Server mode: the server stack trace was included in SQLException messages. Fixed.
</li><li>Views support has been partially re-implemented. Views are up to 6 times faster.
Compared to regular queries, only 20% overhead. Because this is a bigger change,
it is not enabled by default. To enable it, set the system property 'h2.indexNew' to true
(java -Dh2.indexNew=true ..., or in source code Constants.INDEX_NEW = true).
If no problems are found, this will be enabled by default in the next release.
</li><li>In INSERT and MERGE statements, each column may only be specified once now.
</li><li>For most IOExceptions now the file name is included in the error message.
</li><li>A java.util.Date object is now converted to a TIMESTAMP in the JDBC API. Previously it was converted to a DATE.
</li><li>After calling SHUTDOWN and closing the connection and a superfluous error message appeared in the trace file. Fixed.
</li><li>In many situations, views did not use an index if they could have. Fixed. Also the explain plan for views works now.
</li><li>The table id (important for LOB files) is now included in INFORMATION_SCHEMA.TABLES.
</li><li>When using DISTINCT, ORDER BY a function works now as long as it is in the column list.
</li><li>Support for the data type CHAR. The difference to VARCHAR is: trailing spaces are ignored. This
data type is supported for compatibility with other databases and older applications.
</li><li>The aggregate function COUNT(...) now returns a long instead of an int.
</li><li>The 'ordering' of data types was not always correct, for example an operation involving REAL and DOUBLE produced a result of type REAL. Fixed.
</li><li>CSV tool: If the same instance was used for reading and writing, the tool wrote the column names twice. Fixed.
</li><li>Compatibility: Support for the data type notation CHARACTER VARYING.
</li><li>Can now ORDER BY -1 (meaning order by first column, descending), and ORDER BY ? (parameterized column number).
</li><li>Databases with invalid linked tables (for example, because the target database is not accessible) can now be opened.
Old table links don't work however.
</li><li>There was a small memory leak in the trace module. One object per opened connection was kept in a hash map.
</li><li>Linked tables can now emit UPDATE statements if 'EMIT UPDATES' is specified in the CREATE LINKED
TABLE statement. So far, updating a row always deleted the old row and then inserted the new row.
</li><li>In the last release, the H2 Console opened two connection when logging into a database,
and only closed one connection when logging out. Fixed.
</li><li>New functions LEAST and GREATEST to get the smallest or largest value from a list.
</li>
</ul>
<h3>Version 1.0.46 (2007-04-29)</h3><ul>
<li>Unnamed private in-memory database (jdbc:h2:mem:) were not 'private' as documented. Fixed.
</li><li>Autocomplete in the Console application: now the result frame scrolls to the top when the list is updated.
</li><li>GROUP BY expressions did not work correctly in subqueries. Fixed.
</li><li>New function TABLE to define ad-hoc (temporary) tables in a query.
This also solves problems with variable-size IN(...) queries:
instead of SELECT * FROM TEST WHERE ID IN(?, ?, ...) you can now write:
SELECT * FROM TABLE(ID INT=?) X, TEST WHERE X.ID=TEST.ID
In this case, the index is used.
</li><li>New data type ARRAY. Actually it was there before, but is now documented
and better tested (however it must still be considered experimental).
The java.sql.Array implementation is incomplete, but setObject(1, new Object[]{...})
and getObject(..) can be used. New functions ARRAY_GET and ARRAY_LENGTH.
</li><li>SimpleResultSet now has some basic data type conversion features.
</li><li>When using JDK 1.5 or later, and switching on h2.lobFilesInDirectories,
the performance for creating LOBs was bad. This has been fixed, however
creating lots of LOBs it is still faster when the setting is switched off.
</li><li>A problem with multiple unnamed dynamic tables (FROM (SELECT...)) has been fixed.
</li><li>Appending 'Z' to a timestamp did not have an effect. Now it is interpreted as +00:00 (GMT).
</li><li>The BACKUP command is better tested and documented.
This means hot backup (online backup) is now possible.
</li><li>The old 'Backup' tool is now called 'Script' (as the SQL statement).
</li><li>There are new 'Backup' and 'Restore' tools that work with database files directly.
</li><li>The complete syntax for referential and check constraints is now supported
when written as part of the column definition, behind PRIMARY KEY.
</li><li>CASE WHEN ... returned the wrong result when the condition evaluated to NULL.
</li><li>The new function LINK_SCHEMA simplifies linking all tables of a schema.
</li><li>SCRIPT DROP now also drops aliases (Java functions) if they exist.
</li><li>For encrypted databases, the trace option can no longer be enabled manually by creating a file.
</li><li>For linked tables, NULL in the unique key is now supported.
</li><li>For read-only databases, temp files are now created in the default temp directory instead
of the database directory.
</li><li>Sending CLOB data was slow in some systems when using the server version. Fixed.
</li><li>CSVWRITE now returns the number of rows written.
</li><li>The data type of NULLIF was NULL if the first expression was a column. Now the data type is set correctly.
</li><li>Indexes (and other related objects) for local temporary tables where not dropped
when the session was closed. Fixed.
</li><li>ALTER TABLE did not work for tables with computed columns.
</li><li>SQLException.getCause of the now works for JDK 1.4 and higher.
</li><li>If the index file was deleted, an error was logged in the .trace.db file. This is no longer done.
</li><li>The Portuguese (Europe) translation is available. Thanks a lot to Antonio Casqueiro!
</li><li>The error message for invalid views has been improved (the root cause is included in the message now).
</li><li>IN(SELECT ...) was not working correctly if the subquery returned a NULL value. Fixed.
</li><li>DROP ALL OBJECTS did not drop constants.
</li><li>DROP ALL OBJECTS dropped the role PUBLIC, which was wrong. Fixed.
</li><li>CASE was parsed as a function if the expression was in (). Fixed.
</li><li>When ORDER BY was used together with DISTINCT, it was required to type the column
name exactly in the select list and the order list exactly in the same way.
This is not required any longer.
</li></ul>
<h3>Version 1.0.44 (2007-03-04)</h3><ul>
<li>System sequences (automatically created sequences for IDENTITY or AUTO_INCREMENT columns) are now
random (UUIDs) to avoid clashes when merging databases using RUNSCRIPT.
</li><li>The precision for linked tables was not correct for some data types, for example VARCHAR. Fixed.
</li><li>Many problems and bugs in the XA support (package javax.sql) have been fixed.
</li><li>Now the server tool (org.h2.tools.Server) terminates with an exit code if a problem occured.
</li><li>The JDBC driver is now loaded if the JdbcDataSource class is loaded.
</li><li>After renaming a user the password becomes invalid. This is now documented.
</li><li>XAResource.recover didn't work. Fixed.
</li><li>XAResource.recover did throw an exception with the code XAER_OUTSIDE if there
was no connection. Now the code is XAER_RMERR.
</li><li>SCRIPT did not work correctly with BLOB or CLOB data. Fixed.
</li><li>BACKUP TO 'test.zip' now works with encrypted databases and CLOB and BLOB data.
</li><li>The function CASE WHEN ... didn't convert the returned value to the same data type,
resulting in unexpected behavior in many cases. Fixed.
</li><li>Truncating a table is now allowed if the table references another table
(but still not allowed if the table is references by another table).
</li><li>ORDER BY picked the wrong column if the same column name (but with a different table name)
was used twice in the select list.
</li><li>When a subquery was used in the select list of a query, and GROUP BY was used at the same time,
a NullPointerException could occur. Fixed.
</li><li>ORDER BY did not work when DISTINCT was used at the same time in some situations. Fixed.
</li><li>When using IN(...) on a case insensitive column (VARCHAR_IGNORECASE),
an incorrect optimization was made and the result was wrong sometimes.
</li></ul>
<h3>Version 1.0.41 (2007-01-30)</h3><ul>
<li>Experimental online backup feature using the SQL statement BACKUP TO 'fileName'.
This creates a backup in the form of a zip file. Unlike the SCRIPT TO command, the data tables are not locked.
</li><li>When using the server mode, temporary files for large LOB values are now deleted when the result set is closed.
This also means that LOBs become unavailable after closing the result, however this is according to the specs.
</li><li>It was possible that SUM throws a class cast exception if the parameter was a conditional expression.
</li><li>Benchmark: Added a multi-client test case, BenchB (similar to TPC-B).
</li><li>Compatibility: SCHEMA_NAME.SEQUENCE_NAME.NEXTVAL now works as expected.
</li><li>The Console is now translated to Hungarian thanks to Andras Hideg,
and to Indonesian thanks to Joko Yuliantoro
</li><li>XAConnection: A NullPointerException was thrown if addConnectionEventListener was called before opening the connection.
</li><li>In case the result set of a subquery was re-used, an exception was throws if the subquery result did not fit in memory.
Now the result is not re-used in this case. Generally, large subqueries should be avoided for performance reasons.
</li><li>The command "drop all objects delete files" did not work on linux if the database name was lower case.
</li><li>When setting the URL to an empty string the DataSource now throws an better exception.
</li><li>Parsing of LIKE .. ESCAPE did not stop at the expected point. Fixed.
</li><li>Can now use UUID columns as generated key values. However, the UUID column must be the primary key.
</li><li>Improved the Javadoc documentation. Now unsupported features are marked with [Not supported],
and partially supported features are [Partially supported].
</li><li>The forum subscriptions (the emails sent from the forum) now works.
</li></ul>
<h3>Version 1.0.40 (2007-01-17)</h3><ul>
<li>Setting the collation (SET COLLATOR) was very slow on some systems (up to 24 seconds).
Thanks a lot to Martina Nissler for finding this problem!
</li><li>The Console is now translated to Japanese thanks to IKEMOTO, Masahiro (ikeyan (at) arizona (dot) ne (dot) jp)
</li><li>The database engine can now be compiled with JDK 1.3 using ant codeswitch.
There are still some limitations, and the ant script to build the jar does not work yet.
</li><li>Fixed a problem where data in the log file was not written to the data file (recovery failure) after a crash,
if an index was deleted previously.
</li><li>SCRIPT NODATA now writes the row count for each table (this simplifies comparing databases).
</li><li>Selecting a column using the syntax schemaName.tableName.columnName did not work in all cases.
</li><li>Can now parse timestamps with timezone information (Z or +/-hh:mm) and dates before year 1.
However dates before year 1 are not formatted correctly (this is a Java problem).
</li><li>When stopping the TCP server from an application and immediately afterwards staring it again
using a different TCP password, an exception was thrown sometimes.
</li><li>Now PreparedStatement.setBigDecimal(..) can only be called with an object
of type java.math.BigDecimal. Derived classes are not allowed any more. Many thanks to
Maciej Wegorkiewicz for finding this problem.
</li><li>It was possible to manipulate values in the byte array after calling PreparedStatement.setBytes, and this
could lead to problems if the same byte array was used again. Now the byte array is copied if required.
</li><li>Date, time and timestamp objects were cloned in cases where it was not required. Fixed.
</li></ul>
<h3>Version 1.0.36 (2007-01-02)</h3><ul>
<li>It was possible to drop the sequence of a temporary tables with DROP ALL OBJECTS, resulting in a null pointer exception afterwards.
</li><li>Prepared statements with non-constant functions such as CURRENT_TIMESTAMP() did not get re-evaluated if the result of the function changed. Fixed.
</li><li>The (relative or absolute) directory where the script files are stored or read can now be changed using the system property h2.scriptDirectory
</li><li>Client trace files now created in the directory 'trace.db' and no longer the application directory.
This can be changed using the system property h2.clientTraceDirectory.
</li><li>In some situations the log file got corrupt if the process was terminated while the database was opening.
</li><li>Using ;RECOVER=1 in the database URL threw a syntax exception. Fixed.
</li><li>If a CLOB or BLOB was deleted in a transaction and the database crashed before the transaction was committed or rolled back,
the object was lost if it was large. Fixed.
</li><li>Now using ant-build.properties. The jdk is automatically updated when using ant codeswitch...
</li><li>Cluster: Now the server can detect if a query is read-only, and in this case the result is only read from the first cluster node.
However, there is currently no load balancing made to avoid problems with transactions / locking.
</li><li>Many settings are now initialized from system properties and can be changed on the command line without having
recompile the database. See Advances / Settings Read from System Properties.
</li><li>H2 is now available in Maven. The groupId is com.h2database, the artifactId h2 and the version 1.0.20061217.
To create the maven artifacts yourself, use 'ant mavenUploadLocal' and 'ant mavenBuildCentral'.
</li></ul>
<h3>Version 1.0.25 (2006-08-31)</h3><ul>
<li>
In some situations, wide b-tree indexes (with large VARCHAR columns for example) could get corrupted. Fixed.
</li><li>
ORDER BY was broken in the last release when using table aliases. Fixed.
</li><li>Change LOB mechanism (less files, keep index of lob files, point to files and row, delete unused files earlier, maybe bundle files into a tar file)
</li><li>Set the database in an 'exclusive' mode (restrict to one user at a time)
</li><li>Clustering: recovery needs to becomes fully automatic. Global write lock feature.
</li><li>Count index range query (count(*) where id between 10 and 20)
</li><li>Eclipse plugin
</li><li>iReport to support H2
</li><li>Implement missing JDBC API (CallableStatement,...)
</li><li>Sequence: add features [NO] MINVALUE, MAXVALUE, CACHE, CYCLE
</li><li>Compression of the cache
</li><li>Include SMPT (mail) server (at least client) (alert on cluster failure, low disk space,...)
</li><li>Make the jar more modular
</li><li>Drop with restrict (currently cascade is the default)
</li><li>JSON parser and functions
</li><li>Option for Java functions: constant/isDeterministic to allow early evaluation when all parameters are constant
</li><li>Automatic collection of statistics (auto ANALYZE)
</li><li>Server: client ping from time to time (to avoid timeout - is timeout a problem?)
</li><li>Copy database: Tool with config GUI and batch mode, extensible (example: compare)
</li><li>Document, implement tool for long running transactions using user defined compensation statements
</li><li>Support SET TABLE DUAL READONLY
</li><li>Linked schema using CSV files: one schema for a directory of files; support indexes for CSV files
</li><li>Don't write stack traces for common exceptions like duplicate key to the log by default
</li><li>Setting for MAX_QUERY_TIME (default no limit?)
</li><li>GCJ: what is the state now?
</li><li>Convert large byte[]/Strings to streams in the JDBC API (asap).
</li><li>Use Janino to convert Java to C++
</li><li>Reduce disk space usage (Derby uses less disk space?)
</li><li>Events for: Database Startup, Connections, Login attempts, Disconnections, Prepare (after parsing), Web Server (see http://docs.openlinksw.com/virtuoso/fn_dbev_startup.html)
</li><li>Optimization: Log compression
</li><li>Compatibility: in MySQL, HSQLDB, /0.0 is NULL; in PostgreSQL, Derby: Division by zero
</li><li>Functional tables should accept parameters from other tables (see FunctionMultiReturn)
SELECT * FROM TEST T, P2C(T.A, T.R)
</li><li>Custom class loader to reload functions on demand
</li><li>Test http://mysql-je.sourceforge.net/
</li><li>Close all files when closing the database (including LOB files that are open on the client side)
</li><li>Test Connection Pool http://jakarta.apache.org/commons/dbcp
</li><li>Profiler option or profiling tool to find long running and often repeated queries (using DatabaseEventListener API)
</li><li>Function to read/write a file from/to LOB
</li><li>Allow custom settings (@PATH for RUNSCRIPT for example)
</li><li>Performance test: read the data (getString) and use column names to get the data
</li><li>EXE file: maybe use http://jsmooth.sourceforge.net
</li><li>SELECT ... FOR READ WAIT [maxMillisToWait]
</li><li>Automatically delete the index file if opening it fails
</li><li>Performance: Automatically build in-memory indexes if the whole table is in memory
</li><li>H2 Console: The webclient could support more features like phpMyAdmin.
</li><li>The HELP information schema can be directly exposed in the Console
</li><li>Maybe use the 0x1234 notation for binary fields, see MS SQL Server
</li><li>Version column (number/sequence and timestamp based)
</li><li>Optimize getGeneratedKey: send last identity after each execute (server).
</li><li>Date: default date is '1970-01-01' (is it 1900-01-01 in the standard / other databases?)
</li><li>Test and document UPDATE TEST SET (ID, NAME) = (SELECT ID*10, NAME || '!' FROM TEST T WHERE T.ID=TEST.ID);
</li><li>Better space re-use in the files after deleting data (shrink the files)
</li><li>Max memory rows / max undo log size: use block count / row size not row count
</li><li>Index summary is only written if log=2; maybe write it also when log=1 and everything is fine (and no in doubt transactions)
</li><li>Support 123L syntax as in Java; example: SELECT (2000000000*2)
</li><li>Implement point-in-time recovery
</li><li>Memory database: add a feature to keep named database open until 'shutdown'
</li><li>Use the directory of the first script as the default directory for any scripts run inside that script
</li><li>Include the version name in the jar file name
</li><li>Optimize IN(...), IN(select), ID=? OR ID=?: create temp table and use join
</li><li>LIKE: improved version for larger texts (currently using naive search)
</li><li>Auto-reconnect on lost connection to server (even if the server was re-started) except if autocommit was off and there was pending transaction
</li><li>The Script tool should work with other databases as well
</li><li>Automatically convert to the next 'higher' data type whenever there is an overflow.
</li><li>Throw an exception when the application calls getInt on a Long (optional)
</li><li>Default date format for input and output (local date constants)
</li><li>Cache collation keys for performance
</li><li>Convert OR condition to UNION or IN if possible
</li><li>ValueInt.convertToString and so on (remove Value.convertTo)
</li><li>Support custom Collators
</li><li>Document ROWNUM usage for reports: SELECT ROWNUM, * FROM (subquery)
</li><li>Clustering: Reads should be randomly distributed or to a designated database on RAM
</li><li>Clustering: When a database is back alive, automatically synchronize with the master
</li><li>Standalone tool to get relevant system properties and add it to the trace output.
</li><li>Support mixed clustering mode (one embedded, the other server mode)
</li><li>Store dates in local timezone (portability of database files)
</li><li>Ability to resize the cache array when resizing the cache
</li><li>Automatic conversion from WHERE X>10 AND X>20 to X>20
</li><li>Time based cache writing (one second after writing the log)
</li><li>Write a H2 driver for http://db.apache.org/ddlutils/
</li><li>Index usage for REGEXP LIKE.
</li><li>Add a role DBA (like ADMIN).
</li><li>Automatic mode: jdbc:h2:auto: (embedded mode if possible, if not use server mode).
Problem: what to do when server stops while others are connected to it.
</li><li>Access rights: remember the owner of an object. COMMENT: allow owner of object to change it.
</li><li>Implement INSTEAD OF trigger.
</li><li>Access rights: Finer grained access control (grant access for specific functions)
</li><li>Support N'text'
</li><li>Support SCOPE_IDENTITY() to avoid problems when inserting rows in a trigger
</li><li>Support DESCRIBE like MySQL or Oracle (DESC|DESCRIBE {[schema.]object[@connect_identifier]})
</li><li>Set a connection read only (Connection.setReadOnly)
</li><li>In MySQL mode, for AUTO_INCREMENT columns, don't set the primary key
</li><li>Use JDK 1.4 file locking to create the lock file (but not yet by default); writing a system property to detect concurrent access from the same VM (different classloaders).
