The SQL syntax is documented using (railroad) diagrams. The diagrams are HTML.
@changelog_1003_li
The documentation is no longer available in Japanese because the translation was too much out of sync. Please use the Google translation instead.
@changelog_1003_h2
@changelog_1004_li
Certain queries were not sorted if subselect queries were involved
@changelog_1005_li
More bugs in the server-less multi-connection mode have been fixed: 90097 The database is read only, caches must be cleared on reconnect, etc.
@changelog_1006_h2
Version 1.2.121 (2009-10-11)
@changelog_1004_li
@changelog_1007_li
Better support GaeVFS (Google App Engine Virtual File System) thanks to Thanks to Vince Bonfanti.
@changelog_1005_li
@changelog_1008_li
CSVREAD didn't close the file. Thanks to Vince Bonfanti for the patch!
@changelog_1006_li
@changelog_1009_li
If a database in the old format exists, it is now used. The system property is used for new databases, or if databases exist in both formats. In any case, the flag in the URL overrides this logic.
@changelog_1007_li
@changelog_1010_li
Page store bugs were fixed. Large values in indexed columns could corrupt the index.
@changelog_1008_li
@changelog_1011_li
The page store did not work when using Retrotranslator (because the Retrotranslator doesn't support Integer.reverse and Long.reverse).
@changelog_1009_li
@changelog_1012_li
New system property h2.pageStoreTrim to disable shrinking the database when closing (disabled by default, meaning by default the database is trimmed).
@changelog_1010_h2
@changelog_1013_h2
Version 1.2.120 (2009-10-04)
@changelog_1011_li
@changelog_1014_li
This is a beta version.
@changelog_1012_li
@changelog_1015_li
Large updates could throw an ArrayIndexOutOfBoundsException in RowList.writeRow.
@changelog_1013_li
@changelog_1016_li
In version 1.2, the following system properties are now enabled by default: h2.pageStore, h2.nullConcatIsNull, h2.optimizeInList. The default value for h2.defaultMaxLengthInplaceLob is now 4096 (it was 1024 with version 1.1).
@changelog_1014_li
@changelog_1017_li
New databases are now stored in the new 'page store' file format. Existing databases are kept in the old file format. To use the old file format, append ;PAGE_STORE=FALSE to the database URL or set the system property h2.pageStore to false.
@changelog_1015_li
@changelog_1018_li
Issue 125: Renaming primary keys was not persistent. Fixed. Unfortunately, databases created by this version can not be opened with older versions because of this change.
@changelog_1016_li
@changelog_1019_li
Issue 124: Hibernate schema validation failed for decimal/numeric columns. This problem is fixed in the Hibernate dialect that is included with H2 (src/tools/org/hibernate/dialect/H2Dialect.java.txt), but not in Hibernate yet.
@changelog_1017_li
@changelog_1020_li
PostgreSQL compatibility: function LASTVAL() as an alias for IDENTITY().
@changelog_1018_li
@changelog_1021_li
Linked tables now support default values when inserting, updating or merging.
@changelog_1019_li
@changelog_1022_li
Bugfixes in the page store.
@changelog_1020_li
@changelog_1023_li
Possibility to set a vendor id in Constants.java, so that unofficial builds are distinguishable from official releases.
@changelog_1021_li
@changelog_1024_li
Allow writing to linked tables in readonly databases.
@changelog_1022_h2
@changelog_1025_h2
Version 1.1.119 (2009-09-26)
@changelog_1023_li
@changelog_1026_li
SQL statements in the exception message are no longer included if they contain '--hide--'.
@changelog_1024_li
@changelog_1027_li
Temporary local tables did not always work after reconnect if AUTO_SERVER=TRUE
@changelog_1025_li
@changelog_1028_li
New system property h2.defaultMaxLengthInplaceLob to change the default maximum size of an in-place LOB object.
@changelog_1026_li
@changelog_1029_li
New system property h2.nullConcatIsNull to change the default null concatenation behavior. The default will be enabled in version 1.2.
@changelog_1027_li
@changelog_1030_li
The cache algorithm TQ is disabled in this version, because it is unstable, and because the current implementation does not have any measurable advantages over the default.
@changelog_1028_li
@changelog_1031_li
New committer: Christian Peter. He works for <a href="http://www.docware.com">Docware</a> and helped a lot finding and fixing bugs, and generally improving the database. He is now a committer.
@changelog_1029_li
@changelog_1032_li
ChangeFileEncryption did not work with Lob subdirectories. Fixed.
@changelog_1030_li
@changelog_1033_li
Issue 121: JaQu: new simple update and merge methods.
@changelog_1031_li
@changelog_1034_li
Issue 120: JaQu didn't close result sets.
@changelog_1032_li
@changelog_1035_li
Issue 119: JaQu creates wrong WHERE conditions on some inputs.
@changelog_1033_li
@changelog_1036_li
The new page store mechanism is now alpha-level quality. The next release will most likely be "1.2.120 beta" where this mode is enabled by default. To use it right now, append ;PAGE_STORE=TRUE to the database URL. The file format of this mode will probably not change any more.
@changelog_1034_li
@changelog_1037_li
SELECT COUNT(*) FROM SYSTEM_RANGE(...) returned the wrong result. Fixed.
@changelog_1035_li
@changelog_1038_li
The Recover tool now also processes the log files, however applying those changes is still a manual process.
@changelog_1036_li
@changelog_1039_li
New sample application that shows how to pass data to a trigger.
@changelog_1037_li
@changelog_1040_li
More bugs in the server-less multi-connection mode have been fixed: On Windows, two processes could write to the same database at the same time.
@changelog_1038_li
@changelog_1041_li
When loading triggers or other client classes (static functions, database event listener, user aggregate functions, other JDBC drivers), the database now uses the context class loader if the class could not be found using Class.forName().
@changelog_1039_li
@changelog_1042_li
Updating many rows with the same CLOB or BLOB values could result in FileNotFoundException.
@changelog_1040_li
@changelog_1043_li
Statement.getConnection() threw an exception if the connection was already closed.
@changelog_1041_li
@changelog_1044_li
The native fulltext index kept a reference to a database after the database was closed.
@changelog_1042_li
@changelog_1045_li
Non-unique in-memory hash indexes are now supported. Thanks a lot to Sergi Vladykin for the patch!
@changelog_1043_li
@changelog_1046_li
The optimizer does a better job for joins if indexes are missing.
@changelog_1044_h2
@changelog_1047_h2
Version 1.1.118 (2009-09-04)
@changelog_1045_li
@changelog_1048_li
SHOW COLUMNS only listed indexed columns.
@changelog_1046_li
@changelog_1049_li
When calling SHUTDOWN IMMEDIATELY in the server mode, the .trace.db file was not closed.
@changelog_1047_li
@changelog_1050_li
DatabaseMetaData.getPrimaryKeys: the wrong constraint name was reported if there was another constraint on the same table and columns.
@changelog_1048_li
@changelog_1051_li
AUTO_INCREMENT now works in the same way in ALTER TABLE ALTER COLUMN as in CREATE TABLE (it does not create a primary key).
@changelog_1049_li
@changelog_1052_li
Native fulltext search: before searching, FT_INIT() had to be called. This is no longer required.
@changelog_1050_li
@changelog_1053_li
Better support GaeVFS (Google App Engine Virtual File System).
@changelog_1051_li
@changelog_1054_li
JaQu: the plan is to support natural (pure Java / Scala) conditions such as (id == 1 && name.equals("Test")). A proof of concept decompiler is now included (it doesn't work yet).
@changelog_1052_li
@changelog_1055_li
Various bugfixes and improvements in the page store mechanism (still experimental).
@changelog_1053_li
@changelog_1056_li
PreparedStatement.setObject now converts a java.lang.Character to a string.
@changelog_1054_li
@changelog_1057_li
H2 Console: PierPaolo Ucchino has completed the Italian translation. Thanks a lot!
@changelog_1055_li
@changelog_1058_li
Various tools now use Java 5 var-args, such as main the methods and SimpleResultSet.addRow.
@changelog_1056_li
@changelog_1059_li
H2 Console: indexes of tables of non-default schemas are now also listed.
@changelog_1057_li
@changelog_1060_li
Issue 111: Multi-version concurrency / duplicate primary key after rollback.
@changelog_1058_li
@changelog_1061_li
Issue 110: Multi-version concurrency / wrong exception is thrown.
@changelog_1059_li
@changelog_1062_li
Parser: sequenceName.NEXTVAL and CURRVAL did not respect the schema search path.
@changelog_1060_li
@changelog_1063_li
Issue 101: The following sequence could throw the exception "Row not found when trying to delete": start a transaction, insert many rows, delete many rows, rollback. The number of rows depends on the cache size.
@changelog_1061_li
@changelog_1064_li
The stack trace of very common exceptions is no longer written to the .trace.db file by default.
@changelog_1062_li
@changelog_1065_li
An optimization for OR is implemented, but disabled by default. Expressions of the type X=1 OR X=2 are converted to X IN(1, 2). To enable, set the system property h2.optimizeInList to true before loading the H2 JDBC driver.
@changelog_1063_li
@changelog_1066_li
An optimization for IN(..) and IN(SELECT...) is implemented, but disabled by default. To enable, set the system property h2.optimizeInList to true before loading the H2 JDBC driver. If enabled, this overrides h2.optimizeIn and h2.optimizeInJoin. Unlike now, this optimization will also speed up updates and deletes.
@changelog_1064_h2
@changelog_1067_h2
Version 1.1.117 (2009-08-09)
@changelog_1065_li
@changelog_1068_li
New committer: Sam Van Oort has been contributing to H2 since quite some time in many ways (on the mailing list, documentation, and in the form of patches). He is now a committer.
@changelog_1066_li
@changelog_1069_li
JaQu: the order of the fields in the database no longer needs to match the order in the database.
@changelog_1067_li
@changelog_1070_li
Issue 103: MVCC: the setting MAX_MEMORY_UNDO can currently not be supported when using multi-version concurrency, that means the complete undo log must fit in memory.
@changelog_1068_li
@changelog_1071_li
LIKE: the escape mechanism can now be disable using ESCAPE ''. The default escape character can be changed using the system property h2.defaultEscape. The default is still '\' (as in MySQL and PostgreSQL).
@changelog_1069_li
@changelog_1072_li
Views using functions were not re-evaluated when necessary.
@changelog_1070_li
@changelog_1073_li
Improved MySQL compatibility for SHOW COLUMNS.
@changelog_1071_li
@changelog_1074_li
Improved PostgreSQL compatibility for timestamp literals with timezone.
@changelog_1072_li
@changelog_1075_li
Sergi Vladykin translated the error messages to Russian. Thanks a lot!
@changelog_1073_li
@changelog_1076_li
Support for Java 6 DatabaseMetaData.getTables, getColumns, getProcedures, and getProcedureColumns.
@changelog_1074_li
@changelog_1077_li
Issue 101: Rollback of a large transaction (more than 100000 rows) could fail.
@changelog_1075_li
@changelog_1078_li
Various bugfixes and improvements in the page store mechanism (still experimental).
@changelog_1076_li
@changelog_1079_li
The functions LENGTH, OCTET_LENGTH, and BIT_LENGTH now return BIGINT.
@changelog_1077_li
@changelog_1080_li
Data types CLOB and BLOB: the maximum precision was Integer.MAX_VALUE, it is now Long.MAX_VALUE.
@changelog_1078_li
@changelog_1081_li
Multi-threaded kernel: creating and dropping temporary database objects and the potentially free pages list was not correctly synchronized. Thanks a lot to Eric Faulhaber for the test case and patch!
@changelog_1079_li
@changelog_1082_li
Parsing SQL script files is now faster.
@changelog_1080_li
@changelog_1083_li
CSV reading is now faster.
@changelog_1081_li
@changelog_1084_li
SimpleResultSet.newInstance(SimpleRowSource rs) did not work.
@changelog_1082_h2
@changelog_1085_h2
Version 1.1.116 (2009-07-18)
@changelog_1083_li
@changelog_1086_li
Server-less multi-connection mode: more bugs are fixed.
@changelog_1084_li
@changelog_1087_li
The built-in help (INFORMATION_SCHEMA.HELP) is smaller, shrinking the jar file size a bit.
@changelog_1085_li
@changelog_1088_li
H2 Console: column of tables of non-default schemas are now also listed, except for schemas starting with 'INFO'.
@changelog_1086_li
@changelog_1089_li
ALTER TABLE: removing an auto-increment or identity column didn't remove the sequence.
@changelog_1087_li
@changelog_1090_li
Creating indexes is now a bit faster.
@changelog_1088_li
@changelog_1091_li
PG Server: new system property h2.pgClientEncoding to explicitly set the encoding for clients that don't send the encoding (the default encoding is UTF-8). Thanks a lot to Sergi Vladykin for the patch!
@changelog_1089_li
@changelog_1092_li
PG Server: improved compatibility by using the type ids of the PostgreSQL driver. Thanks a lot to Sergi Vladykin for the patch!
@changelog_1090_li
@changelog_1093_li
H2 Console: Oracle system tables are no longer listed, improving performance.
@changelog_1091_li
@changelog_1094_li
Result sets are now read-only except if the statement or prepared statement was created with the concurrency ResultSet.CONCUR_UPDATABLE. This change is required because the old behavior (all result set are updatable) violated the JDBC spec. For backward compatibility, use the system property h2.defaultResultSetConcurrency.
@changelog_1092_li
@changelog_1095_li
New system property h2.defaultResultSetConcurrency to change the default result set concurrency.
@changelog_1093_li
@changelog_1096_li
JDBC: using an invalid result set type or concurrency now throws an exception.
@changelog_1094_li
@changelog_1097_li
If a pooled connection was not closed but garbage collected, a NullPointerException could occur.
@changelog_1095_li
@changelog_1098_li
Fulltext search: a NullPointerException was thrown when updating a value that was NULL previously.
@changelog_1096_li
@changelog_1099_li
The Recover tool did not work with .data.db files of the wrong size.
@changelog_1097_li
@changelog_1100_li
Triggers: if there was an exception when initializing a trigger, this exception could be hidden, and in some cases (specially when using the Lucene fulltext index mechanism) a NullPointerException was thrown later on. Now the exception that occurred on init is thrown when changing data.
@changelog_1098_li
@changelog_1101_li
The soft-references cache (CACHE_TYPE=SOFT_LRU) could throw a NullPointerException.
@changelog_1099_li
@changelog_1102_li
To enable the new page store mechanism, append ;PAGE_STORE=TRUE to the database URL. or set the system property h2.pageStore to true. This mechanism is still experimental, and the file format will change, but it is quite stable now.
@changelog_1100_h2
@changelog_1103_h2
Version 1.1.115 (2009-06-21)
@changelog_1101_li
@changelog_1104_li
The new storage mechanism is now alpha quality. To try it out, set the system property "h2.pageStore" to "true" (java -Dh2.pageStore=true). There are still bugs to be found and fixed, for example inserting many rows references a lot of main memory. Performance is currently about the same as with the regular storage mechanism, but the database file size is smaller. The file format is not stable yet.
@changelog_1102_li
@changelog_1105_li
ALTER TABLE could throw an exception "object already exists" in some cases.
@changelog_1103_li
@changelog_1106_li
Views: in some situations, an ArrayIndexOutOfBoundsException was thrown when using the same view concurrently.
@changelog_1104_li
@changelog_1107_li
java.util.UUID is now supported in PreparedStatement.setObject and user defined Java functions. ResultSet.getObject() returns a java.util.UUID when using the UUID data type.
@changelog_1105_li
@changelog_1108_li
H2 Console: the language was reset to the browser language when disconnecting.
@changelog_1106_li
@changelog_1109_li
H2 Console: improved Polish translation.
@changelog_1107_li
@changelog_1110_li
Server-less multi-connection mode: more bugs are fixed.
@changelog_1108_li
@changelog_1111_li
The download page now included the SHA1 checksums.
@changelog_1109_li
@changelog_1112_li
Shell tool: the file encoding workaround is now documented if you run java org.h2.tools.Shell -?.
@changelog_1110_li
@changelog_1113_li
The RunScript tool and SQL statement did not work with the compression method LZF.
@changelog_1111_li
@changelog_1114_li
Fulltext search: searching for NULL or an empty string threw an exception.
@changelog_1112_li
@changelog_1115_li
Lucene fulltext search: FTL_DROP_ALL did not drop the triggers.
@changelog_1113_li
@changelog_1116_li
Backup: if the database contained CLOB or BLOB data, the backup included a file entry for the LOB directory. This caused the restore to fail.
@changelog_1114_li
@changelog_1117_li
Data types: LONG is now an alias for BIGINT.
@changelog_1115_h2
@changelog_1118_h2
Version 1.1.114 (2009-06-01)
@changelog_1116_li
@changelog_1119_li
ResultSetMetaData.getColumnClassName returned the wrong class for CLOB and BLOB columns.
@changelog_1117_li
@changelog_1120_li
Fulltext search: data is no longer deleted and re-inserted if the indexed columns didn't change.
@changelog_1118_li
@changelog_1121_li
In some situations, an ArrayIndexOutOfBoundsException was thrown when adding rows. This was caused by a bug in the b-tree code.
@changelog_1119_li
@changelog_1122_li
Microsoft Windows Vista: when using the the installer, Vista wrote "This program may not have installed correctly." This message should no longer appear (in the h2.nsi file, the line 'RequestExecutionLevel highest' was added).
@changelog_1120_li
@changelog_1123_li
The Recover tool did not always work when the database contains referential integrity constraints.
@changelog_1121_li
@changelog_1124_li
Java 1.5 is now required to run H2. If required, Retrotranslator can be used to create a Java 1.4 version (http://retrotranslator.sourceforge.net/).
@changelog_1122_h2
@changelog_1125_h2
Version 1.1.113 (2009-05-21)
@changelog_1123_li
@changelog_1126_li
Shell tool: the built-in commands EXIT, HELP, ?, LIST, and so on didn't work with a semicolon at the end.
@changelog_1124_li
@changelog_1127_li
JDK 1.5 is now required to build the jar file. However it is still possible to create a jar file for Java 1.4. For details, see buildRelease.sh and buildRelease.bat. As an alternative, compile using JDK 1.5 or 1.6 and use Retrotranslator to create a Java 1.4 version (http://retrotranslator.sourceforge.net/).
@changelog_1125_li
@changelog_1128_li
When deleting or updating many rows in a table, the space in the index file was not re-used in the default mode (persistent database, b-tree index, LOG=1). This caused the index file to grow over time. Workarounds were to delete and re-created the index file, alter the table (add a remove a column), or append ;LOG=2 to the database URL. To disable the change, set the system property h2.reuseSpaceBtreeIndex to false.
@changelog_1126_li
@changelog_1129_li
Identifiers with a digit and then a dollar sign didn't work. Example: A1$B.
@changelog_1127_li
@changelog_1130_li
MS SQL Server compatibility: support for linked tables with NVARCHAR, NCHAR, NCLOB, and LONGNVARCHAR.
@changelog_1128_li
@changelog_1131_li
Android: workaround for a problem when using read-only databases in zip files (skip seems to be implemented incorrectly on the Android system).
@changelog_1129_li
@changelog_1132_li
Calling execute() or prepareStatement() with null as the SQL statement now throws an exception.
@changelog_1130_li
@changelog_1133_li
Benchmark: the number of executed statements was incorrect. The H2 database was loaded at the beginning of the test to collect results, now it is loaded at the very end. Thanks to Fred Toussi from HSQLDB for reporting those problems. However the changed do not affect the relative performance.
@changelog_1131_li
@changelog_1134_li
H2 Console: command line settings are no longer stored in the properties file. They are now only used for the current process, except if they are explicitly saved.
@changelog_1132_li
@changelog_1135_li
Cache: support for a second level soft-references cache. To enable it, append ;CACHE_TYPE=SOFT_LRU (or SOFT_TQ) to the database URL, or set the system property h2.cacheTypeDefault to "SOFT_LRU" / "SOFT_TQ". Enabling the second level cache reduces performance for small databases, but speeds up large databases. It makes sense to use it if the available memory size is unknown. Thanks a lot to Jan Kotek!
@changelog_1133_h2
@changelog_1136_h2
Version 1.1.112 (2009-05-01)
@changelog_1134_li
@changelog_1137_li
JdbcPreparedStatement.toString() could throw a NullPointerException.
@changelog_1135_li
@changelog_1138_li
EclipseLink: added H2Platform.supportsIdentity().
@changelog_1136_li
@changelog_1139_li
Connection pool: the default login timeout is now 5 minutes.
@changelog_1137_li
@changelog_1140_li
After truncating tables, opening large databases could become slow because indexes were always re-built unnecessarily when opening.
@changelog_1138_li
@changelog_1141_li
More bugs in the server-less multi-connection mode have been fixed: Sometimes parameters of prepared statements were lost when a reconnecting. Concurrent read operations were slow. To improve performance, executeQuery(..) must be used for queries (execute(..) switches to the write mode, which is slow).
@changelog_1139_li
@changelog_1142_li
GROUP BY queries with a self-join (join to the same table) that were grouped by columns with indexes returned the wrong result in some cases.
@changelog_1140_li
@changelog_1143_li
Improved error message when the .lock.db file modification time is in the future.
@changelog_1141_li
@changelog_1144_li
The MERGE statement now returns 0 as the generated key if the row was updated.
@changelog_1142_li
@changelog_1145_li
Running code coverage is now automated.
@changelog_1143_li
@changelog_1146_li
A file system implementation can now be registered using FileSystem.register.
@changelog_1144_li
@changelog_1147_li
The database file system is no longer included in the jar file, it moved to the test section.
@changelog_1145_h2
@changelog_1148_h2
Version 1.1.111 (2009-04-10)
@changelog_1146_li
@changelog_1149_li
In-memory databases can now run inside the Google App Engine.
@changelog_1147_li
@changelog_1150_li
Queries that are ordered by an indexed column returned no rows in certain cases (if all rows were deleted from the table previously, and there is a low number of rows in the table, and when not using other conditions, and when using the default b tree index).
@changelog_1148_li
@changelog_1151_li
The wrong exception was thrown when using unquoted text for the SQL statements COMMENT, ALTER USER, and SET PASSWORD.
@changelog_1149_li
@changelog_1152_li
The built-in connection pool did not roll back transactions and enable autocommit enabled after closing a connection.
@changelog_1150_li
@changelog_1153_li
Sometimes a StackOverflow occurred when checking for deadlock. See also http://code.google.com/p/h2database/issues/detail?id=61
@changelog_1151_li
@changelog_1154_li
The Shell tool no longer truncates results with only one column, and displays a message if data was truncated.
@changelog_1152_h2
@changelog_1155_h2
Version 1.1.110 (2009-04-03)
@changelog_1153_li
@changelog_1156_li
Support for not persistent in-memory tables in regular (persistent) databases using CREATE MEMORY TABLE(..) NOT PERSISTENT. Thanks a lot to Sergi Vladykin for the patch!
@changelog_1154_li
@changelog_1157_li
The H2 Console trimmed the password (removed leading and trailing spaces). This is no longer the case, to support encrypted H2 database with an empty user password.
@changelog_1155_li
@changelog_1158_li
The data type of a SUBSTRING method was wrong.
@changelog_1156_li
@changelog_1159_li
ResultSet.findColumn and get methods with column label parameters now also check for matching column names (like most databases except MySQL).
@changelog_1157_li
@changelog_1160_li
H2 Console: the browser system property now supports a list of arguments. Example: java -Dh2.browser="open,-a,Safari,%url" ...
@changelog_1158_li
@changelog_1161_li
Improved Javadoc navigation (similar to Scaladoc).
@changelog_1159_li
@changelog_1162_li
H2 Console: auto-complete of identifiers did not work correctly for H2 databases in MySQL mode.
@changelog_1160_li
@changelog_1163_li
DISTINCT and GROUP BY on a CLOB column was broken.
@changelog_1161_li
@changelog_1164_li
The FTP server moved to the tools section and is no longer included in the h2*.jar file.
@changelog_1162_li
@changelog_1165_li
Improved error message for unsupported features: now the message says what exactly is not supported.
@changelog_1163_li
@changelog_1166_li
Improved OSGi support.
@changelog_1164_li
@changelog_1167_li
Some internal caches did not use the LRU mechanism. Fixed (LOB file list, optimizer cost cache, trace system, view indexes, collection keys, compressed in-memory file system).
@changelog_1165_li
@changelog_1168_li
The API of the tools changed a bit (each tool now returns an exit code).
@changelog_1166_li
@changelog_1169_li
Command line help of the tools now match the javadocs. The build converts the javadocs to a resource that is read by the tool at runtime. This should not have an effect on using the database, but it reduces duplicate and out-of-sync documentation.
@changelog_1167_li
@changelog_1170_li
CREATE TABLE: improved compatibility (support for UNIQUE NOT NULL).
@changelog_1168_li
@changelog_1171_li
DatabaseMetaData.getSQLKeywords now returns the correct list.
@changelog_1169_li
@changelog_1172_li
Deterministic user defined functions did not work when the parameter was a column. Fixed.
@changelog_1170_li
@changelog_1173_li
JdbcConnectionPool.setLoginTimeout with 0 now uses the default timeout.
@changelog_1171_li
@changelog_1174_li
Creating a JdbcConnectionPool has been simplified a bit.
@changelog_1172_li
@changelog_1175_li
The built-in connection pool did not re-use connections. Getting a connection using the built-in JdbcConnectionPool is now about 70 times faster than opening connections using DriverManager.getConnection.
@changelog_1173_li
@changelog_1176_li
More bugs in the server-less multi-connection mode have been fixed: If a process terminated while writing, other open connections were blocked. If two processes were writing to the database, sometimes the database was corrupt after closing.
@changelog_1174_li
@changelog_1177_li
Linked tables to SQLite database can now be created.
@changelog_1175_li
@changelog_1178_li
Nested IN(IN(...)) didn't work.
@changelog_1176_li
@changelog_1179_li
NIO storage: the nio: prefix was using memory mapped files instead of FileChannel.
@changelog_1177_h2
@changelog_1180_h2
Version 1.1.109 (2009-03-14)
@changelog_1178_li
@changelog_1181_li
The optimization for IN(...) is now only used if comparing a column with an index.
@changelog_1179_li
@changelog_1182_li
User defined functions can now be deterministic (see CREATE ALIAS documentation).
@changelog_1180_li
@changelog_1183_li
Multiple nested queries in the FROM clause with parameters did not always work.
@changelog_1181_li
@changelog_1184_li
When converting CLOB to BINARY, each character resulted in one byte. Now, the text is parsed as a hex as when converting VARCHAR.
@changelog_1182_li
@changelog_1185_li
New experimental NIO storage mechanism with both FileChannel and memory mapped files. To use it, use the file name prefix nio: or nioMapped: as in jdbc:h2:nio:~/test. So far it looks like NIO storage is faster on Mac OS but slower on some Windows systems. Thanks a lot to Jan Kotek for the patch!
@changelog_1183_li
@changelog_1186_li
The functions BITOR, BITAND, BITXOR, and MOD now accept and return BIGINT instead of INT.
@changelog_1184_li
@changelog_1187_li
Could not use the same linked table multiple times in the same query.
@changelog_1185_li
@changelog_1188_li
Bugs in the server-less multi-connection mode have been fixed.
@changelog_1186_li
@changelog_1189_li
Column names could not be named "UNIQUE" (with the quotes).
@changelog_1187_li
@changelog_1190_li
New system function TRANSACTION_ID() to get the current transaction identifier for a session.
@changelog_1188_h2
@changelog_1191_h2
Version 1.1.108 (2009-02-28)
@changelog_1189_li
@changelog_1192_li
When the shutdown hook closed the database, the last log file was deleted too early. This could cause uncommitted changes to be persisted. In some cases, this could cause data corruption.
@changelog_1190_li
@changelog_1193_li
JdbcConnectionPool: it was possible to set a negative connection pool size.
@changelog_1191_li
@changelog_1194_li
Fulltext search did not support table names with a backslash.
@changelog_1192_li
@changelog_1195_li
The internal IntArray class did not work correctly when initialized with a zero length array.
@changelog_1193_li
@changelog_1196_li
The H2 Console web application (war file) did only support ASCII characters. Now UTF-8 is supported.
@changelog_1194_li
@changelog_1197_li
DATEADD does no longer require that the argument is a timestamp.
@changelog_1195_li
@changelog_1198_li
The database file locking mechanism didn't work correctly on Mac OS.
@changelog_1196_li
@changelog_1199_li
Some built-in functions reported the wrong precision, scale, and display size.
@changelog_1197_li
@changelog_1200_li
MySQL compatibility for CREATE TABLE is improved (UNSIGNED, KEY).
@changelog_1198_li
@changelog_1201_li
Recovery did not work if there were more than 255 lobs stored as files.
@changelog_1199_li
@changelog_1202_li
New experimental mode to support multiple read-write connections without starting a server. To enable this mode, append ;FILE_LOCK=SERIALIZED;OPEN_NEW=TRUE to the database URL. Don't expect high performance when multiple concurrent writers.
@changelog_1200_li
@changelog_1203_li
In a web application, the database classes are not unloaded if a connection is open. This may cause out of memory when re-deploying a web application. The DbStarter is changed to close all connections to the configured database (by executing SHUTDOWN).
@changelog_1201_li
@changelog_1204_li
The WebServlet did not close the database when un-deploying the web application.
@changelog_1202_li
@changelog_1205_li
The exception message of failed INSERT or MERGE statements now includes all values and the row number.
@changelog_1203_li
@changelog_1206_li
If opening a database failed with an out of memory exception, some files were not closed.
@changelog_1204_li
@changelog_1207_li
Optimizer: the expected runtime calculation was incorrect. The fixed calculation should give slightly better query plans when using many joins.
@changelog_1205_li
@changelog_1208_li
Improved exception message when connecting to a just started server fails.
@changelog_1206_li
@changelog_1209_li
Connection.isValid is a bit faster.
@changelog_1207_li
@changelog_1210_li
H2 Console: the autocomplete feature has been improved a bit. It can now better parse conditions.
@changelog_1208_li
@changelog_1211_li
When restarting a web application in Tomcat, an exception was thrown sometimes. In most cases this was a NullPointerException. A workaround in H2 has been implemented. The root cause of the problem is now documented in the FAQ: Tomcat sets all static fields (final or non-final) to null when unloading a web application. A workaround is to put the h2.jar in the lib directory, or set the system property org.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES to false.
@changelog_1209_h2
@changelog_1212_h2
Version 1.1.107 (2009-01-24)
@changelog_1210_li
@changelog_1213_li
Some DatabaseMetaData operations did not work for non-admin users for versions 1.1.x.
@changelog_1211_li
@changelog_1214_li
The MySQL compatibility extension fromUnixTime now used the English locale.
@changelog_1212_li
@changelog_1215_li
When using LOG=2 and repeatedly updating the last row rows of a table, the index file grew quickly.
@changelog_1213_li
@changelog_1216_li
In versions 1.1.105 and 1.1.106, encrypted script files of earlier versions could not be processed. This is now again possible. The problem was that such script files were stored in a special format (STORAGE=TEXT) but support for this format was removed in version 1.1.105.
@changelog_1214_li
@changelog_1217_li
Enabling the trace mechanism by creating a specially named file is no longer supported.
@changelog_1215_h2
@changelog_1218_h2
Version 1.1.106 (2009-01-04)
@changelog_1216_li
@changelog_1219_li
Statement.setQueryTimeout did not work correctly for some statements.
@changelog_1217_li
@changelog_1220_li
CREATE DOMAIN: built-in data types can now only be changed if no tables exist.
@changelog_1218_li
@changelog_1221_li
Linked tables: a workaround for Oracle DATE columns has been implemented.
@changelog_1219_li
@changelog_1222_li
DatabaseMetaData.getPrimaryKeys: the column PK_NAME now contains the constraint name instead of the index name (compatibility for PostgreSQL and Derby).
@changelog_1220_li
@changelog_1223_li
Using IN(..) inside a IN(SELECT..) did not always work.
@changelog_1221_li
@changelog_1224_li
Views with IN(..) that used a view itself did not work.
@changelog_1222_li
@changelog_1225_li
Union queries with LIMIT or ORDER BY that are used in a view or subquery did not work.
@changelog_1223_li
@changelog_1226_li
The license change a bit: so far the license was modified to say 'Swiss law'. This is now changed back to the original 'US law'. This was requested by a user, and I don't see a problem.
@changelog_1224_li
@changelog_1227_li
Constraints for local temporary tables now session scoped. So far they were global. Thanks a lot to Eric Faulhaber for finding and fixing this problem!
@changelog_1225_li
@changelog_1228_li
When using the auto-server mode, and if the lock file was modified in the future, the wrong exception was thrown ('Connection is broken' instead of 'Error opening database: lock file modified in the future').
@changelog_1226_h2
@changelog_1229_h2
Version 1.1.105 (2008-12-19)
@changelog_1227_li
@changelog_1230_li
The setting STORAGE=TEXT is no longer supported.
@changelog_1228_li
@changelog_1231_li
Deleting a database using the tool DeleteDbFiles deleted LOB files of other databases in the same directory.
@changelog_1229_li
@changelog_1232_li
When used in a subquery, LIKE and IN(..) did not work correctly sometimes.
@changelog_1230_li
@changelog_1233_li
The fulltext search documentation has been improved.
@changelog_1231_li
@changelog_1234_li
ARRAY_GET returned the wrong data type (ARRAY). Now it returns VARCHAR.
@changelog_1232_li
@changelog_1235_li
Natural join: the joined columns are not repeated any more when using SELECT *.
@changelog_1233_li
@changelog_1236_li
User defined aggregate functions: the method getType expected internal data types instead of SQL types.
@changelog_1234_li
@changelog_1237_li
User defined aggregate functions did not work if there was no group by expression.
@changelog_1235_li
@changelog_1238_li
MySQL compatibility: support for := assignment as in @sum:=@sum+x
@changelog_1236_li
@changelog_1239_li
INSERT INTO TEST(SELECT * FROM TEST) is now supported.
@changelog_1237_li
@changelog_1240_li
Each session threw an invisible exception when garbage collected.
@changelog_1238_li
@changelog_1241_li
Foreign key constraints that refer to a quoted column did not work.
@changelog_1239_li
@changelog_1242_li
New meta data column INFORMATION_SCHEMA.TABLES.LAST_MODIFICATION to get the table modification counter.
@changelog_1240_li
@changelog_1243_li
Shell: line comments didn't work correctly.
@changelog_1241_li
@changelog_1244_li
H2 Console: columns are now listed for up to 500 tables instead of 100.
@changelog_1242_li
@changelog_1245_li
H2 Console: Cmd+Enter executes the current statement, Alt+Space for autocomplete.
@changelog_1243_li
@changelog_1246_li
JaQu: the maximum length of a column can now be defined using maxLength. For an example, see Product.java (maxLength(category, 255)).
@changelog_1244_li
@changelog_1247_li
Rıdvan Ağar has completed the Turkish translation of the H2 Console. Thanks a lot!
@changelog_1245_h2
@changelog_1248_h2
Version 1.1.104 (2008-11-28)
@changelog_1246_li
@changelog_1249_li
If a query that was used like a table contained group by and was ordered by an expression that is not in the column list, an exception was thrown.
@changelog_1247_li
@changelog_1250_li
JaQu: tables are now auto-created when running a query.
@changelog_1248_li
@changelog_1251_li
The optimizer had problems with function tables (for example CSVREAD and FTL_SEARCH). A new system property h2.estimatedFunctionTableRows (default 1000) defines how many rows can be expected in the table.
@changelog_1249_li
@changelog_1252_li
The function SUM could overflow when using large values. It returns now a data type that is safe.
@changelog_1250_li
@changelog_1253_li
The function AVG could overflow when using large values. Fixed.
@changelog_1251_li
@changelog_1254_li
The emergency reserve file has been removed. It didn't provide an appropriate solution for the problem. It is still possible for an application to detect and deal with the low disk space problem (deleting temporary files for example) using DatabaseEventListener.diskSpaceIsLow, but this method is now always called with stillAvailable=0.
@changelog_1252_li
@changelog_1255_li
Build: JAVA_HOME is now automatically detected on Mac OS X.
@changelog_1253_li
@changelog_1256_li
Testing for local connections was very slow on some systems.
@changelog_1254_li
@changelog_1257_li
The cache memory usage calculation is more conservative.
@changelog_1255_li
@changelog_1258_li
Allocating space got slower and slower the larger the database.
@changelog_1256_li
@changelog_1259_li
ALTER TABLE ALTER COLUMN could throw the wrong exception in the last version (Table not found).
@changelog_1257_li
@changelog_1260_li
Updatable result sets: the key columns can now be updated.
@changelog_1258_li
@changelog_1261_li
The H2DatabaseProvider for ActiveObjects is now included in the tools section.
@changelog_1259_li
@changelog_1262_li
The H2Platform for Oracle Toplink Essential has been improved a bit.
@changelog_1260_li
@changelog_1263_li
The Windows service to start H2 didn't work in version 1.1.
@changelog_1261_li
@changelog_1264_li
File systems with a maximum file size (for example FAT) are now supported using the file prefix 'split:'. In this case the files are split in parts of 1 GB. Example URL: jdbc:h2:split:~/db/test. If you want to split into parts of 1 MB, use jdbc:h2:split:20:~/db/test (the part size is 1 << x, the default is 30 meaning 1 GB).
@changelog_1262_li
@changelog_1265_li
The database now tries to detect if the classloader or virtual machine has almost shut down by checking if static final variables are set to null. This should help reduce exceptions when stopping the web application.
@changelog_1263_li
@changelog_1266_li
Compatibility for MS SQL Server DATEDIFF(YYYY, .., ..)
@changelog_1264_li
@changelog_1267_li
ResultSet.getObject for CLOB or BLOB will return a java.sql.Clob / java.sql.Blob object instead of a java.io.Reader / java.io.InputStream as in version 1.0. This behavior can be changed using the system property h2.returnLobObjects (true by default for version 1.1).
@changelog_1265_li
@changelog_1268_li
The interface CloseListener has a new method 'remove' that is called when the trigger is dropped.
@changelog_1266_li
@changelog_1269_li
Fulltext search: there was a memory leak when creating and dropping fulltext indexes in a loop.
@changelog_1267_h2
@changelog_1270_h2
Version 1.1.103 (2008-11-07)
@changelog_1268_li
@changelog_1271_li
Could not order by a formula when the formula was in the group by list but not in the select list.
@changelog_1269_li
@changelog_1272_li
Date values that match the daylight saving time end were not allowed in times zones were the daylight saving time ends at midnight, for years larger than 2037. Example: timezone Brasilia, date 2042-10-12. This is a problem of Java, however a workaround is implemented in H2 that solves most problems (except the problems of java.util.Date itself).
@changelog_1270_li
@changelog_1273_li
ALTER TABLE used a lot of memory when using multi-version concurrency.
@changelog_1271_li
@changelog_1274_li
Referential integrity for in-memory databases didn't work in some cases in version 1.1.102.
@changelog_1272_li
@changelog_1275_li
New column INFORMATION_SCHEMA.COLUMNS.SEQUENCE_NAME to get the name of the sequence for auto-increment columns.
@changelog_1273_li
@changelog_1276_li
Aliases for built-in data types (such as MEDIUMBLOB which is an alias for BLOB) can now be re-mapped to another data type using CREATE DOMAIN. However main built-in data types (such as INTEGER) can not be re-mapped.
@changelog_1274_li
@changelog_1277_li
The Japanese translation has been completed by Masahiro Ikemoto. Thanks a lot!
@changelog_1275_li
@changelog_1278_li
Improved PostgreSQL compatibility for NEXTVAL and CURRVAL.
@changelog_1276_li
@changelog_1279_li
Less heap memory is needed when multiple databases are open at the same time: the memory reserve (used to rollback after out of memory) is now global and no longer allocated for each database separately.
@changelog_1277_li
@changelog_1280_li
New system property h2.browser to set the browser to use.
@changelog_1278_li
@changelog_1281_li
To start the browser, java.awt.Desktop.browse is now used if available.
@changelog_1279_h2
@changelog_1282_h2
Version 1.1.102 (2008-10-24)
@changelog_1280_li
@changelog_1283_li
The French translation of the H2 Console has been improved by Olivier Parent. Thanks a lot!
@changelog_1281_li
@changelog_1284_li
There was a memory leak when creating and dropping tables and indexes in a loop (persistent database only).
@changelog_1282_li
@changelog_1285_li
SET LOG 2 was not effective if executed after opening the database.
@changelog_1283_li
@changelog_1286_li
Translating the H2 Console is now simpler.
@changelog_1284_li
@changelog_1287_li
Common exception (error code 23*) are no longer written to the .trace.db file by default.
@changelog_1285_li
@changelog_1288_li
In-memory databases don't write LOBs to files any longer.
@changelog_1286_li
@changelog_1289_li
Self referencing constraints didn't restrict deleting rows that reference itself if there is another row that references it.
@changelog_1287_li
@changelog_1290_li
ResultSetMetaData.getColumnName now returns the alias name except for columns.
@changelog_1288_li
@changelog_1291_li
Temporary files are now deleted when the database is closed, even if they were not garbage collected so far.
@changelog_1289_h2
@changelog_1292_h2
Version 1.1.101 (2008-10-17)
@changelog_1290_li
@changelog_1293_li
Errors with code 42000 - 42999 are no longer written to the trace file by default.
@changelog_1291_li
@changelog_1294_li
Queries with more than 10 tables are now faster.
@changelog_1292_li
@changelog_1295_li
Opening a connection with AUTO_SERVER=TRUE is now fast when the database is already open in another process (less than 0.01 seconds instead of 2 seconds).
@changelog_1293_li
@changelog_1296_li
IF [NOT] EXISTS is supported for named constraints in ALTER TABLE ... ADD/DROP CONSTRAINT.
@changelog_1294_li
@changelog_1297_li
The error messages have been translated to Spanish by Dario V. Fassi. Thanks a lot!
@changelog_1295_li
@changelog_1298_li
Linked tables: the automatic connection sharing didn't work. Actually the system property h2.shareLinkedConnections was working in the opposite direction: it was disabled when set to true. Now it works as expected.
@changelog_1296_li
@changelog_1299_li
Opening large database is now faster.
@changelog_1297_li
@changelog_1300_li
New system property h2.socketConnectTimeout, the timeout in milliseconds to connect to a server. The default is 2000 (2 seconds).
@changelog_1298_li
@changelog_1301_li
The wrong parameters were bound to subqueries with parameters, specially when using IN(SELECT ...) and IN(...).
@changelog_1299_li
@changelog_1302_li
Unset parameters were not detected when the query was re-compiled.
@changelog_1300_li
@changelog_1303_li
New functions ISO_YEAR, ISO_WEEK, ISO_DAY_OF_WEEK. Thanks a lot to Robert Rathsack for implementing those!
@changelog_1301_li
@changelog_1304_li
The date functions DAYOFYEAR, DAYOFMONTH, DAYOFWEEK are now called DAY_OF_YEAR, DAY_OF_MONTH, DAY_OF_WEEK (the old names still work).
@changelog_1302_li
@changelog_1305_li
An out of memory error while deleting or updating many rows could result in a strange exception.
@changelog_1303_li
@changelog_1306_li
Linked tables: compatibility with MS SQL Server has been improved.
@changelog_1304_li
@changelog_1307_li
Renaming tables that have foreign keys with cascade didn't work correctly.
@changelog_1305_li
@changelog_1308_li
The auto-reconnect feature didn't work when using the auto-server mode. Fixed.
@changelog_1306_li
@changelog_1309_li
Fulltext search: new method FT_DROP_INDEX.
@changelog_1307_li
@changelog_1310_li
The optimization to group using an index didn't work in some cases in version 1.1 (see also system property h2.optimizeGroupSorted).
@changelog_1308_li
@changelog_1311_li
OSGi meta data is included in the manifest file. An OSGi BundleActivator is included: it loads the database driver when starting the bundle, and unloads it when stopping the bundle.
@changelog_1309_li
@changelog_1312_li
The default value for MAX_MEMORY_UNDO is now 50000.
@changelog_1310_li
@changelog_1313_li
For alias columns, ResultSetMetaData.getTableName() and getColumnName() now return the real table and column name in the default mode.
@changelog_1311_li
@changelog_1314_li
In SQL scripts created with SCRIPT TO, schemas are now only created if they don't exist yet.
@changelog_1312_li
@changelog_1315_li
After re-connecting to a database, the database event listener (if set) is informed about it.
@changelog_1313_li
@changelog_1316_li
Local temporary tables now support indexes. Thanks a lot to Matt Roy!
@changelog_1314_li
@changelog_1317_li
RUNSCRIPT no longer uses a temporary file.
@changelog_1315_li
@changelog_1318_li
New system table INFORMATION_SCHEMA.SESSION_STATE containing the SQL statements that make up the session state. The list currently contains variables (SET @..) and local temporary tables (without data).
@changelog_1316_li
@changelog_1319_li
After an automatic re-connect, part of the session state stays (the part that is stored in the SESSION_STATE table).
@changelog_1317_li
@changelog_1320_li
The build didn't work if the directory temp didn't exist before.
@changelog_1318_li
@changelog_1321_li
New system property h2.maxReconnect (default 3) to limit the number of re-connects for the same SQL statement (this is usually only important for SHUTDOWN).
@changelog_1319_li
@changelog_1322_li
WHERE .. IN (SELECT ...) could throw a NullPointerException.
@changelog_1320_li
@changelog_1323_li
Improved Glassfish / Toplink support in H2Platform thanks to Marcio Borges from Brazil. Thanks a lot!
@changelog_1321_h2
@changelog_1324_h2
Version 1.1.100 (2008-10-04)
@changelog_1322_li
@changelog_1325_li
In version 1.1, the following system properties are now enabled by default: h2.lobFilesInDirectories, h2.optimizeGroupSorted, h2.optimizeInJoin, h2.shareLinkedConnections
@changelog_1323_li
@changelog_1326_li
The H2 Console tool now works with the JDBC-ODBC bridge.
@changelog_1324_li
@changelog_1327_li
The H2 Console tool now supports command line options to start things separately.
@changelog_1325_li
@changelog_1328_li
Large objects did not work for in-memory databases in server mode in Linux.
@changelog_1326_li
@changelog_1329_li
Connections from a local address other than 'localhost' were not allowed if remote connections were disabled. This was always a problem, but only got visible in the last release because the server no longer connects to 'localhost' if networked.
@changelog_1327_li
@changelog_1330_li
The h2console.war can now be built using the Java build.
@changelog_1328_li
@changelog_1331_li
By default, databases are shared in the same process. For read-only databases this causes unnecessary synchronization, but safes memory. If you want that each connection opens its own database, append ;OPEN_NEW=TRUE to the database URL.
@changelog_1329_li
@changelog_1332_li
New auto-reconnect feature will cause the JDBC driver to reconnect to the database if the connection is lost. To enable, append ;AUTO_RECONNECT=TRUE to the database URL. This is specially helpful when using AUTO_SERVER. AUTO_SERVER automatically uses auto-reconnect.
@changelog_1330_li
@changelog_1333_li
CreateCluster: the property 'serverlist' is now called 'serverList'.
@changelog_1331_li
@changelog_1334_li
The ConvertTraceFile tool could not parse some files because the trace mechanism did not encode prepared statement parameters.
@changelog_1332_li
@changelog_1335_li
Databases names can now be one character long (the minimum size used to be 2 characters).
@changelog_1333_h2
@changelog_1336_h2
Version 1.0.79 (2008-09-26)
@changelog_1334_li
@changelog_1337_li
Linked tables that point to the same database can now share the connection within the same database. Access to the same connection is serialized. To enable this feature, set the system property h2.shareLinkedConnections to true.
@changelog_1335_li
@changelog_1338_li
Multiple processes can now access the same database without having to explicitly start the server. To do that, append ;AUTO_SERVER=TRUE to the database URL. In this case, the server is started automatically if the connection is in embedded mode, and the server mode is used if a server is running. If the process that opened the first connection is closed, the other client need to reconnect (there is no automatic re-connect so far). Remote connections are allowed, but only to this database.
@changelog_1336_li
@changelog_1339_li
The server tool now displays the correct IP address if networked.
@changelog_1337_li
@changelog_1340_li
Can now start a TCP server with port 0 (automatically select a port).
@changelog_1338_li
@changelog_1341_li
Result sets with just a unique index can now be updated (previously a primary key was required).
@changelog_1339_li
@changelog_1342_li
LINKED TABLE: the schema name can now be set. When multiple tables exist in different schema, and the schema name is not set, an exception is thrown.
@changelog_1340_li
@changelog_1343_li
LINKED TABLE: worked around a bug in Oracle with the CHAR data type.
@changelog_1341_li
@changelog_1344_li
Faster hash code calculation for large binary arrays.
@changelog_1342_li
@changelog_1345_li
Faster storage re-use algorithm thanks to Greg Dhuse from cleversafe.com.
@changelog_1343_li
@changelog_1346_li
The database supports the SHOW command for better MySQL and PostgreSQL compatibility.
@changelog_1344_li
@changelog_1347_li
The H2 Console now abbreviates large texts in results.
@changelog_1345_li
@changelog_1348_li
Multiple UNION queries could not be used in derived tables.
@changelog_1346_li
@changelog_1349_li
Linked tables can now be read-only.
@changelog_1347_li
@changelog_1350_li
Temporary linked tables are now supported.
@changelog_1348_li
@changelog_1351_li
It was possible to create tables in read-only databases.
@changelog_1349_li
@changelog_1352_li
SET SCHEMA_SEARCH_PATH is now documented.
@changelog_1350_li
@changelog_1353_li
SET SCHEMA did not work for views.
@changelog_1351_li
@changelog_1354_li
Row level locking for MVCC is now enabled. The exception 'Concurrent update in table ...' is still thrown, but only after the lock timeout.
@changelog_1352_li
@changelog_1355_li
The maximum log file size setting was ignored for large databases.
@changelog_1353_li
@changelog_1356_li
Multi-Version Concurrency (MVCC) may no longer be used when using the multi-threaded kernel feature (MULTI_THREADED). An exception is thrown when trying to connect with both settings. Additional synchronization is required before those features can be used together.
@changelog_1354_li
@changelog_1357_li
The data type JAVA_OBJECT could not be used in updatable result sets.
@changelog_1355_li
@changelog_1358_li
The system property h2.optimizeInJoin did not work correctly.
@changelog_1356_li
@changelog_1359_li
Conditions such as ID=? AND ID < ? were slow.
@changelog_1357_h2
@changelog_1360_h2
Version 1.0.78 (2008-08-28)
@changelog_1358_li
@changelog_1361_li
The documentation no longer uses a frameset (except the Javadocs).
@changelog_1359_li
@changelog_1362_li
When using DB_CLOSE_DELAY, sometimes a NullPointerException is thrown when the database is opened almost at the same time as it is closed automatically. Thanks a lot to Dmitry Pekar for finding this!
@changelog_1360_li
@changelog_1363_li
Java methods with variable number of parameters can now be used (for Java 1.5 or newer).
@changelog_1361_li
@changelog_1364_li
The Japanese translation has been improved by Masahiro Ikemoto. Thanks a lot!
@changelog_1362_li
@changelog_1365_li
The H2 Console replaced an empty user name with a single space.
@changelog_1363_li
@changelog_1366_li
The build target 'build jarSmall' now includes the embedded database.
@changelog_1364_li
@changelog_1367_li
JdbcDataSource now keeps the password in a char array where possible.
@changelog_1365_li
@changelog_1368_li
ResultSet.absolute did not always work with large result sets.
@changelog_1366_li
@changelog_1369_li
Column aliases can now be used in GROUP BY and HAVING.
@changelog_1367_li
@changelog_1370_li
Jason Brittain has contributed MySQL date functions. Thanks a lot! They are not in the h2.jar file currently, but in src/tools/org/h2/mode/FunctionsMySQL.java. To install, add this class to the classpath and call FunctionsMySQL.register(conn) in the Java code.
@changelog_1368_h2
@changelog_1371_h2
Version 1.0.77 (2008-08-16)
@changelog_1369_li
@changelog_1372_li
JaQu is now using prepared statements and supports Date, Time, Timestamp.
@changelog_1370_li
@changelog_1373_li
When using remote in-memory databases, large LOB objects did not work.
@changelog_1371_li
@changelog_1374_li
Timestamp columns such as TIMESTAMP(6) were not compatible to other database.
@changelog_1372_li
@changelog_1375_li
Opening a large database was slow if there was a problem opening the previous time.
@changelog_1373_li
@changelog_1376_li
NOT IN(SELECT ...) was incorrect if the subquery returns no rows.
@changelog_1374_li
@changelog_1377_li
CREATE TABLE AS SELECT did not work correctly in the multi-version concurrency mode.
@changelog_1375_li
@changelog_1378_li
Support a comma before closing a list, as in: create table test(id int,)
@changelog_1376_li
@changelog_1379_li
MySQL compatibility: linked tables had lower case column names on some systems.
@changelog_1377_li
@changelog_1380_li
DB2 compatibility: the DB2 fetch-first-clause is supported.
@changelog_1378_li
@changelog_1381_li
Oracle compatibility: old style outer join syntax using (+) did work correctly sometimes.
@changelog_1379_li
@changelog_1382_li
ResultSet.setFetchSize is now supported.
@changelog_1380_li
@changelog_1383_li
It has been reported that when using Install4j on some Linux systems and enabling the 'pack200' option, the h2.jar becomes corrupted by the install process, causing application failure. A workaround is to add an empty file h2.jar.nopack next to the h2.jar file. The reason for this problem is not known.
@changelog_1381_h2
@changelog_1384_h2
Version 1.0.76 (2008-07-27)
@changelog_1382_li
@changelog_1385_li
The comment of a domain (user defined data type) is now used as the default column comment when creating a column with this domain.
@changelog_1383_li
@changelog_1386_li
Invalid database names are now detected and a better error message is thrown.
@changelog_1384_li
@changelog_1387_li
ResultSetMetaData.getColumnClassName now returns the correct class name for BLOB and CLOB.
@changelog_1385_li
@changelog_1388_li
Fixed the Oracle mode: Oracle allows multiple rows only where all columns of the unique index are NULL.
@changelog_1386_li
@changelog_1389_li
There is a problem with Hibernate when using Boolean columns. A patch for Hibernate has been submitted at http://opensource.atlassian.com/projects/hibernate/browse/HHH-3401
@changelog_1387_li
@changelog_1390_li
ORDER BY on tableName.columnName didn't work correctly if the column name was also used as an alias.
@changelog_1388_li
@changelog_1391_li
H2 Console: the progress display when opening a database has been improved.
@changelog_1389_li
@changelog_1392_li
The error message when the server doesn't start has been improved.
@changelog_1390_li
@changelog_1393_li
Key values can now be changed in updatable result sets.
@changelog_1391_li
@changelog_1394_li
Changes in updatable result sets are now visible even when resetting the result set.
@changelog_1392_li
@changelog_1395_li
Temporary files were sometimes deleted too late when executing large insert, update, or delete operations.
@changelog_1393_li
@changelog_1396_li
The database file was growing after deleting many rows, and after large update operations.
Usually, bugs get fixes as they are found. There is a release every few weeks. Here is the list of known and confirmed issues:
@faq_1014_li
@faq_1015_li
Tomcat and Glassfish 3 set most static fields (final or non-final) to <code>null</code> when unloading a web application. This can cause a <code>NullPointerException</code> in H2 versions 1.1.107 and older, and may still not work in newer versions. Please report it if you run into this issue. In Tomcat >= 6.0 this behavior can be disabled by setting the system property <code>org.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES=false</code>, however Tomcat may then run out of memory. A known workaround is to put the <code>h2*.jar</code> file in a shared <code>lib</code> directory (<code>common/lib</code>).
@faq_1015_li
@faq_1016_li
Some problems have been found with right outer join. Internally, it is converted to left outer join, which does not always produce the same results as other databases when used in combination with other joins.
@faq_1016_li
@faq_1017_li
When using Install4j before 4.1.4 on Linux and enabling <code>pack200</code>, the <code>h2*.jar</code> becomes corrupted by the install process, causing application failure. A workaround is to add an empty file <code>h2*.jar.nopack</code> next to the <code>h2*.jar</code> file. This problem is solved in Install4j 4.1.4.
@faq_1017_h3
@faq_1018_h3
Is this Database Engine Open Source?
@faq_1018_p
@faq_1019_p
Yes. It is free to use and distribute, and the source code is included. See also under license.
@faq_1019_h3
@faq_1020_h3
My Query is Slow
@faq_1020_p
@faq_1021_p
Slow <code>SELECT</code> (or <code>DELETE, UPDATE, MERGE</code>) statement can have multiple reasons. Follow this checklist:
@faq_1021_li
@faq_1022_li
Run <code>ANALYZE</code> (see documentation for details).
@faq_1022_li
@faq_1023_li
Run the query with <code>EXPLAIN</code> and check if indexes are used (see documentation for details).
@faq_1023_li
@faq_1024_li
If required, create additional indexes and try again using <code>ANALYZE</code> and <code>EXPLAIN</code>.
@faq_1024_li
@faq_1025_li
If it doesn't help please report the problem.
@faq_1025_h3
@faq_1026_h3
How to Create a New Database?
@faq_1026_p
@faq_1027_p
By default, a new database is automatically created if it does not yet exist. See <a href="tutorial.html#creating_new_databases">Creating New Databases</a>.
@faq_1027_h3
@faq_1028_h3
How to Connect to a Database?
@faq_1028_p
@faq_1029_p
The database driver is <code>org.h2.Driver</code>, and the database URL starts with <code>jdbc:h2:</code>. To connect to a database using JDBC, use the following code:
@faq_1029_h3
@faq_1030_h3
Where are the Database Files Stored?
@faq_1030_p
@faq_1031_p
When using database URLs like <code>jdbc:h2:~/test</code>, the database is stored in the user directory. For Windows, this is usually <code>C:\Documents and Settings\<userName></code>. If the base directory is not set (as in <code>jdbc:h2:test</code>), the database files are stored in the directory where the application is started (the current working directory). When using the H2 Console application from the start menu, this is <code><Installation Directory>/bin</code>. The base directory can be set in the database URL. A fixed or relative path can be used. When using the URL <code>jdbc:h2:file:data/sample</code>, the database is stored in the directory <code>data</code> (relative to the current working directory). The directory is created automatically if it does not yet exist. It is also possible to use the fully qualified directory name (and for Windows, drive name). Example: <code>jdbc:h2:file:C:/data/test</code>
@faq_1031_h3
@faq_1032_h3
What is the Size Limit (Maximum Size) of a Database?
@faq_1032_p
@faq_1033_p
See <a href="advanced.html#limits_limitations">Limits and Limitations</a>.
@faq_1033_h3
@faq_1034_h3
Is it Reliable?
@faq_1034_p
@faq_1035_p
That is not easy to say. It is still a quite new product. A lot of tests have been written, and the code coverage of these tests is very high. Randomized stress tests are run regularly. But there are probably still bugs that have not yet been found (as with most software). Some features are known to be dangerous, they are only supported for situations where performance is more important than reliability. Those dangerous features are:
@faq_1035_li
@faq_1036_li
Disabling the transaction log mechanism using <code>SET LOG 0</code>.
@faq_1036_li
@faq_1037_li
Using the transaction isolation level <code>READ_UNCOMMITTED</code> (<code>LOCK_MODE 0</code>) while at the same time using multiple connections.
@faq_1037_li
@faq_1038_li
Disabling database file protection using <code>FILE_LOCK=NO</code> in the database URL.
@faq_1038_li
@faq_1039_li
Disabling referential integrity using <code>SET REFERENTIAL_INTEGRITY FALSE</code>.
@faq_1039_p
@faq_1040_p
In addition to that, running out of memory should be avoided. In older versions, OutOfMemory errors while using the database could corrupt a databases.
@faq_1040_p
@faq_1041_p
Areas that are not fully tested:
@faq_1041_li
@faq_1042_li
Platforms other than Windows XP, Linux, Mac OS X, or JVMs other than Sun 1.5 or 1.6
@faq_1042_li
@faq_1043_li
The features <code>AUTO_SERVER</code> and <code>AUTO_RECONNECT</code>
@faq_1043_li
@faq_1044_li
The MVCC (multi version concurrency) mode
@faq_1044_li
@faq_1045_li
Cluster mode, 2-phase commit, savepoints
@faq_1045_li
@faq_1046_li
24/7 operation
@faq_1046_li
@faq_1047_li
Some operations on databases larger than 500 MB may be slower than expected
@faq_1047_li
@faq_1048_li
The optimizer may not always select the best plan
@faq_1048_li
@faq_1049_li
Fulltext search
@faq_1049_li
@faq_1050_li
Operations on LOBs over 2 GB
@faq_1050_p
@faq_1051_p
Areas considered experimental are:
@faq_1051_li
@faq_1052_li
The PostgreSQL server
@faq_1052_li
@faq_1053_li
Multi-threading within the engine using <code>SET MULTI_THREADED=1</code>
@faq_1053_li
@faq_1054_li
Compatibility modes for other databases (only some features are implemented)
@faq_1054_p
@faq_1055_p
Some users have reported that after a power failure, the database can sometimes not be opened because the index file is corrupt. In that case, the index file can be deleted (it is automatically re-created). To avoid this, append <code>;LOG=2</code> to the database URL. See also: <a href="grammar.html#set_log" class="notranslate">SET LOG</a>. This problem will be solved using the new 'page store' mechanism (currently beta).
@faq_1055_h3
@faq_1056_h3
Column Names are Incorrect?
@faq_1057_p
For the query <code>SELECT ID AS X FROM TEST</code> the method <code>ResultSetMetaData.getColumnName()</code> returns <code>ID</code>, I expect it to return <code>X</code>. What's wrong?
@faq_1058_p
This is not a bug. According the the JDBC specification, the method <code>ResultSetMetaData.getColumnName()</code> should return the name of the column and not the alias name. If you need the alias name, use <a href="http://java.sun.com/javase/6/docs/api/java/sql/ResultSetMetaData.html#getColumnLabel(int)"><code>ResultSetMetaData.getColumnLabel()</code></a>. Other database don't work like this (they don't follow the JDBC standard). If you need compatibility with those databases, use the <a href="features.html#compatibility">Compatibility Mode</a>, or set the system property <a href="../javadoc/org/h2/constant/SysProperties.html#h2.aliasColumnName"><code>h2.aliasColumnName</code></a>.
@faq_1059_h3
Why is Opening my Database Slow?
@faq_1056_p
@faq_1060_p
If it takes a long time to open a database, in most cases it was not closed the last time. This is specially a problem for larger databases. To close a database, close all connections to it before the application ends, or execute the command <code>SHUTDOWN</code>. The database is also closed when the virtual machine exits normally by using a shutdown hook. However killing a Java process or calling <code>Runtime.halt</code> will prevent this. The reason why opening is slow in this situations is that indexes are re-created. If you can not guarantee the database is closed, consider using <a href="grammar.html#set_log" class="notranslate">SET LOG 2</a>.
@faq_1057_p
@faq_1061_p
To find out what the problem is, open the database in embedded mode using the H2 Console. This will print progress information. If you have many lines with 'Creating index' it is an indication that the database was not closed the last time.
@faq_1058_p
@faq_1062_p
Other possible reasons are: the database is very big (many GB), or contains linked tables that are slow to open.
@faq_1059_h3
@faq_1063_h3
Is the GCJ Version Stable? Faster?
@faq_1060_p
@faq_1064_p
The GCJ version is not as stable as the Java version. When running the regression test with the GCJ version, sometimes the application just stops at what seems to be a random point without error message. Currently, the GCJ version is also slower than when using the Sun VM. However, the startup of the GCJ version is faster than when using a VM.
@faq_1061_h3
@faq_1065_h3
How to Translate this Project?
@faq_1062_p
@faq_1066_p
For more information, see <a href="build.html#translating">Build/Translating</a>.
@features_1000_h1
...
...
@@ -4697,79 +4718,79 @@ Cache Settings
To get information about page reads and writes, and the current caching algorithm in use, call <code>SELECT * FROM INFORMATION_SCHEMA.SETTINGS</code>. The number of pages read / written is listed for the data and index file.
#The SQL syntax is documented using (railroad) diagrams. The diagrams are HTML.
@changelog_1003_li
#The documentation is no longer available in Japanese because the translation was too much out of sync. Please use the Google translation instead.
@changelog_1003_h2
@changelog_1004_li
#Certain queries were not sorted if subselect queries were involved
@changelog_1005_li
#More bugs in the server-less multi-connection mode have been fixed: 90097 The database is read only, caches must be cleared on reconnect, etc.
@changelog_1006_h2
#Version 1.2.121 (2009-10-11)
@changelog_1004_li
@changelog_1007_li
#Better support GaeVFS (Google App Engine Virtual File System) thanks to Thanks to Vince Bonfanti.
@changelog_1005_li
@changelog_1008_li
#CSVREAD didn't close the file. Thanks to Vince Bonfanti for the patch!
@changelog_1006_li
@changelog_1009_li
#If a database in the old format exists, it is now used. The system property is used for new databases, or if databases exist in both formats. In any case, the flag in the URL overrides this logic.
@changelog_1007_li
@changelog_1010_li
#Page store bugs were fixed. Large values in indexed columns could corrupt the index.
@changelog_1008_li
@changelog_1011_li
#The page store did not work when using Retrotranslator (because the Retrotranslator doesn't support Integer.reverse and Long.reverse).
@changelog_1009_li
@changelog_1012_li
#New system property h2.pageStoreTrim to disable shrinking the database when closing (disabled by default, meaning by default the database is trimmed).
@changelog_1010_h2
@changelog_1013_h2
#Version 1.2.120 (2009-10-04)
@changelog_1011_li
@changelog_1014_li
#This is a beta version.
@changelog_1012_li
@changelog_1015_li
#Large updates could throw an ArrayIndexOutOfBoundsException in RowList.writeRow.
@changelog_1013_li
@changelog_1016_li
#In version 1.2, the following system properties are now enabled by default: h2.pageStore, h2.nullConcatIsNull, h2.optimizeInList. The default value for h2.defaultMaxLengthInplaceLob is now 4096 (it was 1024 with version 1.1).
@changelog_1014_li
@changelog_1017_li
#New databases are now stored in the new 'page store' file format. Existing databases are kept in the old file format. To use the old file format, append ;PAGE_STORE=FALSE to the database URL or set the system property h2.pageStore to false.
@changelog_1015_li
@changelog_1018_li
#Issue 125: Renaming primary keys was not persistent. Fixed. Unfortunately, databases created by this version can not be opened with older versions because of this change.
@changelog_1016_li
@changelog_1019_li
#Issue 124: Hibernate schema validation failed for decimal/numeric columns. This problem is fixed in the Hibernate dialect that is included with H2 (src/tools/org/hibernate/dialect/H2Dialect.java.txt), but not in Hibernate yet.
@changelog_1017_li
@changelog_1020_li
#PostgreSQL compatibility: function LASTVAL() as an alias for IDENTITY().
@changelog_1018_li
@changelog_1021_li
#Linked tables now support default values when inserting, updating or merging.
@changelog_1019_li
@changelog_1022_li
#Bugfixes in the page store.
@changelog_1020_li
@changelog_1023_li
#Possibility to set a vendor id in Constants.java, so that unofficial builds are distinguishable from official releases.
@changelog_1021_li
@changelog_1024_li
#Allow writing to linked tables in readonly databases.
@changelog_1022_h2
@changelog_1025_h2
#Version 1.1.119 (2009-09-26)
@changelog_1023_li
@changelog_1026_li
#SQL statements in the exception message are no longer included if they contain '--hide--'.
@changelog_1024_li
@changelog_1027_li
#Temporary local tables did not always work after reconnect if AUTO_SERVER=TRUE
@changelog_1025_li
@changelog_1028_li
#New system property h2.defaultMaxLengthInplaceLob to change the default maximum size of an in-place LOB object.
@changelog_1026_li
@changelog_1029_li
#New system property h2.nullConcatIsNull to change the default null concatenation behavior. The default will be enabled in version 1.2.
@changelog_1027_li
@changelog_1030_li
#The cache algorithm TQ is disabled in this version, because it is unstable, and because the current implementation does not have any measurable advantages over the default.
@changelog_1028_li
@changelog_1031_li
#New committer: Christian Peter. He works for <a href="http://www.docware.com">Docware</a> and helped a lot finding and fixing bugs, and generally improving the database. He is now a committer.
@changelog_1029_li
@changelog_1032_li
#ChangeFileEncryption did not work with Lob subdirectories. Fixed.
@changelog_1030_li
@changelog_1033_li
#Issue 121: JaQu: new simple update and merge methods.
@changelog_1031_li
@changelog_1034_li
#Issue 120: JaQu didn't close result sets.
@changelog_1032_li
@changelog_1035_li
#Issue 119: JaQu creates wrong WHERE conditions on some inputs.
@changelog_1033_li
@changelog_1036_li
#The new page store mechanism is now alpha-level quality. The next release will most likely be "1.2.120 beta" where this mode is enabled by default. To use it right now, append ;PAGE_STORE=TRUE to the database URL. The file format of this mode will probably not change any more.
@changelog_1034_li
@changelog_1037_li
#SELECT COUNT(*) FROM SYSTEM_RANGE(...) returned the wrong result. Fixed.
@changelog_1035_li
@changelog_1038_li
#The Recover tool now also processes the log files, however applying those changes is still a manual process.
@changelog_1036_li
@changelog_1039_li
#New sample application that shows how to pass data to a trigger.
@changelog_1037_li
@changelog_1040_li
#More bugs in the server-less multi-connection mode have been fixed: On Windows, two processes could write to the same database at the same time.
@changelog_1038_li
@changelog_1041_li
#When loading triggers or other client classes (static functions, database event listener, user aggregate functions, other JDBC drivers), the database now uses the context class loader if the class could not be found using Class.forName().
@changelog_1039_li
@changelog_1042_li
#Updating many rows with the same CLOB or BLOB values could result in FileNotFoundException.
@changelog_1040_li
@changelog_1043_li
#Statement.getConnection() threw an exception if the connection was already closed.
@changelog_1041_li
@changelog_1044_li
#The native fulltext index kept a reference to a database after the database was closed.
@changelog_1042_li
@changelog_1045_li
#Non-unique in-memory hash indexes are now supported. Thanks a lot to Sergi Vladykin for the patch!
@changelog_1043_li
@changelog_1046_li
#The optimizer does a better job for joins if indexes are missing.
@changelog_1044_h2
@changelog_1047_h2
#Version 1.1.118 (2009-09-04)
@changelog_1045_li
@changelog_1048_li
#SHOW COLUMNS only listed indexed columns.
@changelog_1046_li
@changelog_1049_li
#When calling SHUTDOWN IMMEDIATELY in the server mode, the .trace.db file was not closed.
@changelog_1047_li
@changelog_1050_li
#DatabaseMetaData.getPrimaryKeys: the wrong constraint name was reported if there was another constraint on the same table and columns.
@changelog_1048_li
@changelog_1051_li
#AUTO_INCREMENT now works in the same way in ALTER TABLE ALTER COLUMN as in CREATE TABLE (it does not create a primary key).
@changelog_1049_li
@changelog_1052_li
#Native fulltext search: before searching, FT_INIT() had to be called. This is no longer required.
@changelog_1050_li
@changelog_1053_li
#Better support GaeVFS (Google App Engine Virtual File System).
@changelog_1051_li
@changelog_1054_li
#JaQu: the plan is to support natural (pure Java / Scala) conditions such as (id == 1 && name.equals("Test")). A proof of concept decompiler is now included (it doesn't work yet).
@changelog_1052_li
@changelog_1055_li
#Various bugfixes and improvements in the page store mechanism (still experimental).
@changelog_1053_li
@changelog_1056_li
#PreparedStatement.setObject now converts a java.lang.Character to a string.
@changelog_1054_li
@changelog_1057_li
#H2 Console: PierPaolo Ucchino has completed the Italian translation. Thanks a lot!
@changelog_1055_li
@changelog_1058_li
#Various tools now use Java 5 var-args, such as main the methods and SimpleResultSet.addRow.
@changelog_1056_li
@changelog_1059_li
#H2 Console: indexes of tables of non-default schemas are now also listed.
@changelog_1057_li
@changelog_1060_li
#Issue 111: Multi-version concurrency / duplicate primary key after rollback.
@changelog_1058_li
@changelog_1061_li
#Issue 110: Multi-version concurrency / wrong exception is thrown.
@changelog_1059_li
@changelog_1062_li
#Parser: sequenceName.NEXTVAL and CURRVAL did not respect the schema search path.
@changelog_1060_li
@changelog_1063_li
#Issue 101: The following sequence could throw the exception "Row not found when trying to delete": start a transaction, insert many rows, delete many rows, rollback. The number of rows depends on the cache size.
@changelog_1061_li
@changelog_1064_li
#The stack trace of very common exceptions is no longer written to the .trace.db file by default.
@changelog_1062_li
@changelog_1065_li
#An optimization for OR is implemented, but disabled by default. Expressions of the type X=1 OR X=2 are converted to X IN(1, 2). To enable, set the system property h2.optimizeInList to true before loading the H2 JDBC driver.
@changelog_1063_li
@changelog_1066_li
#An optimization for IN(..) and IN(SELECT...) is implemented, but disabled by default. To enable, set the system property h2.optimizeInList to true before loading the H2 JDBC driver. If enabled, this overrides h2.optimizeIn and h2.optimizeInJoin. Unlike now, this optimization will also speed up updates and deletes.
@changelog_1064_h2
@changelog_1067_h2
#Version 1.1.117 (2009-08-09)
@changelog_1065_li
@changelog_1068_li
#New committer: Sam Van Oort has been contributing to H2 since quite some time in many ways (on the mailing list, documentation, and in the form of patches). He is now a committer.
@changelog_1066_li
@changelog_1069_li
#JaQu: the order of the fields in the database no longer needs to match the order in the database.
@changelog_1067_li
@changelog_1070_li
#Issue 103: MVCC: the setting MAX_MEMORY_UNDO can currently not be supported when using multi-version concurrency, that means the complete undo log must fit in memory.
@changelog_1068_li
@changelog_1071_li
#LIKE: the escape mechanism can now be disable using ESCAPE ''. The default escape character can be changed using the system property h2.defaultEscape. The default is still '\' (as in MySQL and PostgreSQL).
@changelog_1069_li
@changelog_1072_li
#Views using functions were not re-evaluated when necessary.
@changelog_1070_li
@changelog_1073_li
#Improved MySQL compatibility for SHOW COLUMNS.
@changelog_1071_li
@changelog_1074_li
#Improved PostgreSQL compatibility for timestamp literals with timezone.
@changelog_1072_li
@changelog_1075_li
#Sergi Vladykin translated the error messages to Russian. Thanks a lot!
@changelog_1073_li
@changelog_1076_li
#Support for Java 6 DatabaseMetaData.getTables, getColumns, getProcedures, and getProcedureColumns.
@changelog_1074_li
@changelog_1077_li
#Issue 101: Rollback of a large transaction (more than 100000 rows) could fail.
@changelog_1075_li
@changelog_1078_li
#Various bugfixes and improvements in the page store mechanism (still experimental).
@changelog_1076_li
@changelog_1079_li
#The functions LENGTH, OCTET_LENGTH, and BIT_LENGTH now return BIGINT.
@changelog_1077_li
@changelog_1080_li
#Data types CLOB and BLOB: the maximum precision was Integer.MAX_VALUE, it is now Long.MAX_VALUE.
@changelog_1078_li
@changelog_1081_li
#Multi-threaded kernel: creating and dropping temporary database objects and the potentially free pages list was not correctly synchronized. Thanks a lot to Eric Faulhaber for the test case and patch!
@changelog_1079_li
@changelog_1082_li
#Parsing SQL script files is now faster.
@changelog_1080_li
@changelog_1083_li
#CSV reading is now faster.
@changelog_1081_li
@changelog_1084_li
#SimpleResultSet.newInstance(SimpleRowSource rs) did not work.
@changelog_1082_h2
@changelog_1085_h2
#Version 1.1.116 (2009-07-18)
@changelog_1083_li
@changelog_1086_li
#Server-less multi-connection mode: more bugs are fixed.
@changelog_1084_li
@changelog_1087_li
#The built-in help (INFORMATION_SCHEMA.HELP) is smaller, shrinking the jar file size a bit.
@changelog_1085_li
@changelog_1088_li
#H2 Console: column of tables of non-default schemas are now also listed, except for schemas starting with 'INFO'.
@changelog_1086_li
@changelog_1089_li
#ALTER TABLE: removing an auto-increment or identity column didn't remove the sequence.
@changelog_1087_li
@changelog_1090_li
#Creating indexes is now a bit faster.
@changelog_1088_li
@changelog_1091_li
#PG Server: new system property h2.pgClientEncoding to explicitly set the encoding for clients that don't send the encoding (the default encoding is UTF-8). Thanks a lot to Sergi Vladykin for the patch!
@changelog_1089_li
@changelog_1092_li
#PG Server: improved compatibility by using the type ids of the PostgreSQL driver. Thanks a lot to Sergi Vladykin for the patch!
@changelog_1090_li
@changelog_1093_li
#H2 Console: Oracle system tables are no longer listed, improving performance.
@changelog_1091_li
@changelog_1094_li
#Result sets are now read-only except if the statement or prepared statement was created with the concurrency ResultSet.CONCUR_UPDATABLE. This change is required because the old behavior (all result set are updatable) violated the JDBC spec. For backward compatibility, use the system property h2.defaultResultSetConcurrency.
@changelog_1092_li
@changelog_1095_li
#New system property h2.defaultResultSetConcurrency to change the default result set concurrency.
@changelog_1093_li
@changelog_1096_li
#JDBC: using an invalid result set type or concurrency now throws an exception.
@changelog_1094_li
@changelog_1097_li
#If a pooled connection was not closed but garbage collected, a NullPointerException could occur.
@changelog_1095_li
@changelog_1098_li
#Fulltext search: a NullPointerException was thrown when updating a value that was NULL previously.
@changelog_1096_li
@changelog_1099_li
#The Recover tool did not work with .data.db files of the wrong size.
@changelog_1097_li
@changelog_1100_li
#Triggers: if there was an exception when initializing a trigger, this exception could be hidden, and in some cases (specially when using the Lucene fulltext index mechanism) a NullPointerException was thrown later on. Now the exception that occurred on init is thrown when changing data.
@changelog_1098_li
@changelog_1101_li
#The soft-references cache (CACHE_TYPE=SOFT_LRU) could throw a NullPointerException.
@changelog_1099_li
@changelog_1102_li
#To enable the new page store mechanism, append ;PAGE_STORE=TRUE to the database URL. or set the system property h2.pageStore to true. This mechanism is still experimental, and the file format will change, but it is quite stable now.
@changelog_1100_h2
@changelog_1103_h2
#Version 1.1.115 (2009-06-21)
@changelog_1101_li
@changelog_1104_li
#The new storage mechanism is now alpha quality. To try it out, set the system property "h2.pageStore" to "true" (java -Dh2.pageStore=true). There are still bugs to be found and fixed, for example inserting many rows references a lot of main memory. Performance is currently about the same as with the regular storage mechanism, but the database file size is smaller. The file format is not stable yet.
@changelog_1102_li
@changelog_1105_li
#ALTER TABLE could throw an exception "object already exists" in some cases.
@changelog_1103_li
@changelog_1106_li
#Views: in some situations, an ArrayIndexOutOfBoundsException was thrown when using the same view concurrently.
@changelog_1104_li
@changelog_1107_li
#java.util.UUID is now supported in PreparedStatement.setObject and user defined Java functions. ResultSet.getObject() returns a java.util.UUID when using the UUID data type.
@changelog_1105_li
@changelog_1108_li
#H2 Console: the language was reset to the browser language when disconnecting.
@changelog_1106_li
@changelog_1109_li
#H2 Console: improved Polish translation.
@changelog_1107_li
@changelog_1110_li
#Server-less multi-connection mode: more bugs are fixed.
@changelog_1108_li
@changelog_1111_li
#The download page now included the SHA1 checksums.
@changelog_1109_li
@changelog_1112_li
#Shell tool: the file encoding workaround is now documented if you run java org.h2.tools.Shell -?.
@changelog_1110_li
@changelog_1113_li
#The RunScript tool and SQL statement did not work with the compression method LZF.
@changelog_1111_li
@changelog_1114_li
#Fulltext search: searching for NULL or an empty string threw an exception.
@changelog_1112_li
@changelog_1115_li
#Lucene fulltext search: FTL_DROP_ALL did not drop the triggers.
@changelog_1113_li
@changelog_1116_li
#Backup: if the database contained CLOB or BLOB data, the backup included a file entry for the LOB directory. This caused the restore to fail.
@changelog_1114_li
@changelog_1117_li
#Data types: LONG is now an alias for BIGINT.
@changelog_1115_h2
@changelog_1118_h2
#Version 1.1.114 (2009-06-01)
@changelog_1116_li
@changelog_1119_li
#ResultSetMetaData.getColumnClassName returned the wrong class for CLOB and BLOB columns.
@changelog_1117_li
@changelog_1120_li
#Fulltext search: data is no longer deleted and re-inserted if the indexed columns didn't change.
@changelog_1118_li
@changelog_1121_li
#In some situations, an ArrayIndexOutOfBoundsException was thrown when adding rows. This was caused by a bug in the b-tree code.
@changelog_1119_li
@changelog_1122_li
#Microsoft Windows Vista: when using the the installer, Vista wrote "This program may not have installed correctly." This message should no longer appear (in the h2.nsi file, the line 'RequestExecutionLevel highest' was added).
@changelog_1120_li
@changelog_1123_li
#The Recover tool did not always work when the database contains referential integrity constraints.
@changelog_1121_li
@changelog_1124_li
#Java 1.5 is now required to run H2. If required, Retrotranslator can be used to create a Java 1.4 version (http://retrotranslator.sourceforge.net/).
@changelog_1122_h2
@changelog_1125_h2
#Version 1.1.113 (2009-05-21)
@changelog_1123_li
@changelog_1126_li
#Shell tool: the built-in commands EXIT, HELP, ?, LIST, and so on didn't work with a semicolon at the end.
@changelog_1124_li
@changelog_1127_li
#JDK 1.5 is now required to build the jar file. However it is still possible to create a jar file for Java 1.4. For details, see buildRelease.sh and buildRelease.bat. As an alternative, compile using JDK 1.5 or 1.6 and use Retrotranslator to create a Java 1.4 version (http://retrotranslator.sourceforge.net/).
@changelog_1125_li
@changelog_1128_li
#When deleting or updating many rows in a table, the space in the index file was not re-used in the default mode (persistent database, b-tree index, LOG=1). This caused the index file to grow over time. Workarounds were to delete and re-created the index file, alter the table (add a remove a column), or append ;LOG=2 to the database URL. To disable the change, set the system property h2.reuseSpaceBtreeIndex to false.
@changelog_1126_li
@changelog_1129_li
#Identifiers with a digit and then a dollar sign didn't work. Example: A1$B.
@changelog_1127_li
@changelog_1130_li
#MS SQL Server compatibility: support for linked tables with NVARCHAR, NCHAR, NCLOB, and LONGNVARCHAR.
@changelog_1128_li
@changelog_1131_li
#Android: workaround for a problem when using read-only databases in zip files (skip seems to be implemented incorrectly on the Android system).
@changelog_1129_li
@changelog_1132_li
#Calling execute() or prepareStatement() with null as the SQL statement now throws an exception.
@changelog_1130_li
@changelog_1133_li
#Benchmark: the number of executed statements was incorrect. The H2 database was loaded at the beginning of the test to collect results, now it is loaded at the very end. Thanks to Fred Toussi from HSQLDB for reporting those problems. However the changed do not affect the relative performance.
@changelog_1131_li
@changelog_1134_li
#H2 Console: command line settings are no longer stored in the properties file. They are now only used for the current process, except if they are explicitly saved.
@changelog_1132_li
@changelog_1135_li
#Cache: support for a second level soft-references cache. To enable it, append ;CACHE_TYPE=SOFT_LRU (or SOFT_TQ) to the database URL, or set the system property h2.cacheTypeDefault to "SOFT_LRU" / "SOFT_TQ". Enabling the second level cache reduces performance for small databases, but speeds up large databases. It makes sense to use it if the available memory size is unknown. Thanks a lot to Jan Kotek!
@changelog_1133_h2
@changelog_1136_h2
#Version 1.1.112 (2009-05-01)
@changelog_1134_li
@changelog_1137_li
#JdbcPreparedStatement.toString() could throw a NullPointerException.
#Connection pool: the default login timeout is now 5 minutes.
@changelog_1137_li
@changelog_1140_li
#After truncating tables, opening large databases could become slow because indexes were always re-built unnecessarily when opening.
@changelog_1138_li
@changelog_1141_li
#More bugs in the server-less multi-connection mode have been fixed: Sometimes parameters of prepared statements were lost when a reconnecting. Concurrent read operations were slow. To improve performance, executeQuery(..) must be used for queries (execute(..) switches to the write mode, which is slow).
@changelog_1139_li
@changelog_1142_li
#GROUP BY queries with a self-join (join to the same table) that were grouped by columns with indexes returned the wrong result in some cases.
@changelog_1140_li
@changelog_1143_li
#Improved error message when the .lock.db file modification time is in the future.
@changelog_1141_li
@changelog_1144_li
#The MERGE statement now returns 0 as the generated key if the row was updated.
@changelog_1142_li
@changelog_1145_li
#Running code coverage is now automated.
@changelog_1143_li
@changelog_1146_li
#A file system implementation can now be registered using FileSystem.register.
@changelog_1144_li
@changelog_1147_li
#The database file system is no longer included in the jar file, it moved to the test section.
@changelog_1145_h2
@changelog_1148_h2
#Version 1.1.111 (2009-04-10)
@changelog_1146_li
@changelog_1149_li
#In-memory databases can now run inside the Google App Engine.
@changelog_1147_li
@changelog_1150_li
#Queries that are ordered by an indexed column returned no rows in certain cases (if all rows were deleted from the table previously, and there is a low number of rows in the table, and when not using other conditions, and when using the default b tree index).
@changelog_1148_li
@changelog_1151_li
#The wrong exception was thrown when using unquoted text for the SQL statements COMMENT, ALTER USER, and SET PASSWORD.
@changelog_1149_li
@changelog_1152_li
#The built-in connection pool did not roll back transactions and enable autocommit enabled after closing a connection.
@changelog_1150_li
@changelog_1153_li
#Sometimes a StackOverflow occurred when checking for deadlock. See also http://code.google.com/p/h2database/issues/detail?id=61
@changelog_1151_li
@changelog_1154_li
#The Shell tool no longer truncates results with only one column, and displays a message if data was truncated.
@changelog_1152_h2
@changelog_1155_h2
#Version 1.1.110 (2009-04-03)
@changelog_1153_li
@changelog_1156_li
#Support for not persistent in-memory tables in regular (persistent) databases using CREATE MEMORY TABLE(..) NOT PERSISTENT. Thanks a lot to Sergi Vladykin for the patch!
@changelog_1154_li
@changelog_1157_li
#The H2 Console trimmed the password (removed leading and trailing spaces). This is no longer the case, to support encrypted H2 database with an empty user password.
@changelog_1155_li
@changelog_1158_li
#The data type of a SUBSTRING method was wrong.
@changelog_1156_li
@changelog_1159_li
#ResultSet.findColumn and get methods with column label parameters now also check for matching column names (like most databases except MySQL).
@changelog_1157_li
@changelog_1160_li
#H2 Console: the browser system property now supports a list of arguments. Example: java -Dh2.browser="open,-a,Safari,%url" ...
@changelog_1158_li
@changelog_1161_li
#Improved Javadoc navigation (similar to Scaladoc).
@changelog_1159_li
@changelog_1162_li
#H2 Console: auto-complete of identifiers did not work correctly for H2 databases in MySQL mode.
@changelog_1160_li
@changelog_1163_li
#DISTINCT and GROUP BY on a CLOB column was broken.
@changelog_1161_li
@changelog_1164_li
#The FTP server moved to the tools section and is no longer included in the h2*.jar file.
@changelog_1162_li
@changelog_1165_li
#Improved error message for unsupported features: now the message says what exactly is not supported.
@changelog_1163_li
@changelog_1166_li
#Improved OSGi support.
@changelog_1164_li
@changelog_1167_li
#Some internal caches did not use the LRU mechanism. Fixed (LOB file list, optimizer cost cache, trace system, view indexes, collection keys, compressed in-memory file system).
@changelog_1165_li
@changelog_1168_li
#The API of the tools changed a bit (each tool now returns an exit code).
@changelog_1166_li
@changelog_1169_li
#Command line help of the tools now match the javadocs. The build converts the javadocs to a resource that is read by the tool at runtime. This should not have an effect on using the database, but it reduces duplicate and out-of-sync documentation.
@changelog_1167_li
@changelog_1170_li
#CREATE TABLE: improved compatibility (support for UNIQUE NOT NULL).
@changelog_1168_li
@changelog_1171_li
#DatabaseMetaData.getSQLKeywords now returns the correct list.
@changelog_1169_li
@changelog_1172_li
#Deterministic user defined functions did not work when the parameter was a column. Fixed.
@changelog_1170_li
@changelog_1173_li
#JdbcConnectionPool.setLoginTimeout with 0 now uses the default timeout.
@changelog_1171_li
@changelog_1174_li
#Creating a JdbcConnectionPool has been simplified a bit.
@changelog_1172_li
@changelog_1175_li
#The built-in connection pool did not re-use connections. Getting a connection using the built-in JdbcConnectionPool is now about 70 times faster than opening connections using DriverManager.getConnection.
@changelog_1173_li
@changelog_1176_li
#More bugs in the server-less multi-connection mode have been fixed: If a process terminated while writing, other open connections were blocked. If two processes were writing to the database, sometimes the database was corrupt after closing.
@changelog_1174_li
@changelog_1177_li
#Linked tables to SQLite database can now be created.
@changelog_1175_li
@changelog_1178_li
#Nested IN(IN(...)) didn't work.
@changelog_1176_li
@changelog_1179_li
#NIO storage: the nio: prefix was using memory mapped files instead of FileChannel.
@changelog_1177_h2
@changelog_1180_h2
#Version 1.1.109 (2009-03-14)
@changelog_1178_li
@changelog_1181_li
#The optimization for IN(...) is now only used if comparing a column with an index.
@changelog_1179_li
@changelog_1182_li
#User defined functions can now be deterministic (see CREATE ALIAS documentation).
@changelog_1180_li
@changelog_1183_li
#Multiple nested queries in the FROM clause with parameters did not always work.
@changelog_1181_li
@changelog_1184_li
#When converting CLOB to BINARY, each character resulted in one byte. Now, the text is parsed as a hex as when converting VARCHAR.
@changelog_1182_li
@changelog_1185_li
#New experimental NIO storage mechanism with both FileChannel and memory mapped files. To use it, use the file name prefix nio: or nioMapped: as in jdbc:h2:nio:~/test. So far it looks like NIO storage is faster on Mac OS but slower on some Windows systems. Thanks a lot to Jan Kotek for the patch!
@changelog_1183_li
@changelog_1186_li
#The functions BITOR, BITAND, BITXOR, and MOD now accept and return BIGINT instead of INT.
@changelog_1184_li
@changelog_1187_li
#Could not use the same linked table multiple times in the same query.
@changelog_1185_li
@changelog_1188_li
#Bugs in the server-less multi-connection mode have been fixed.
@changelog_1186_li
@changelog_1189_li
#Column names could not be named "UNIQUE" (with the quotes).
@changelog_1187_li
@changelog_1190_li
#New system function TRANSACTION_ID() to get the current transaction identifier for a session.
@changelog_1188_h2
@changelog_1191_h2
#Version 1.1.108 (2009-02-28)
@changelog_1189_li
@changelog_1192_li
#When the shutdown hook closed the database, the last log file was deleted too early. This could cause uncommitted changes to be persisted. In some cases, this could cause data corruption.
@changelog_1190_li
@changelog_1193_li
#JdbcConnectionPool: it was possible to set a negative connection pool size.
@changelog_1191_li
@changelog_1194_li
#Fulltext search did not support table names with a backslash.
@changelog_1192_li
@changelog_1195_li
#The internal IntArray class did not work correctly when initialized with a zero length array.
@changelog_1193_li
@changelog_1196_li
#The H2 Console web application (war file) did only support ASCII characters. Now UTF-8 is supported.
@changelog_1194_li
@changelog_1197_li
#DATEADD does no longer require that the argument is a timestamp.
@changelog_1195_li
@changelog_1198_li
#The database file locking mechanism didn't work correctly on Mac OS.
@changelog_1196_li
@changelog_1199_li
#Some built-in functions reported the wrong precision, scale, and display size.
@changelog_1197_li
@changelog_1200_li
#MySQL compatibility for CREATE TABLE is improved (UNSIGNED, KEY).
@changelog_1198_li
@changelog_1201_li
#Recovery did not work if there were more than 255 lobs stored as files.
@changelog_1199_li
@changelog_1202_li
#New experimental mode to support multiple read-write connections without starting a server. To enable this mode, append ;FILE_LOCK=SERIALIZED;OPEN_NEW=TRUE to the database URL. Don't expect high performance when multiple concurrent writers.
@changelog_1200_li
@changelog_1203_li
#In a web application, the database classes are not unloaded if a connection is open. This may cause out of memory when re-deploying a web application. The DbStarter is changed to close all connections to the configured database (by executing SHUTDOWN).
@changelog_1201_li
@changelog_1204_li
#The WebServlet did not close the database when un-deploying the web application.
@changelog_1202_li
@changelog_1205_li
#The exception message of failed INSERT or MERGE statements now includes all values and the row number.
@changelog_1203_li
@changelog_1206_li
#If opening a database failed with an out of memory exception, some files were not closed.
@changelog_1204_li
@changelog_1207_li
#Optimizer: the expected runtime calculation was incorrect. The fixed calculation should give slightly better query plans when using many joins.
@changelog_1205_li
@changelog_1208_li
#Improved exception message when connecting to a just started server fails.
@changelog_1206_li
@changelog_1209_li
#Connection.isValid is a bit faster.
@changelog_1207_li
@changelog_1210_li
#H2 Console: the autocomplete feature has been improved a bit. It can now better parse conditions.
@changelog_1208_li
@changelog_1211_li
#When restarting a web application in Tomcat, an exception was thrown sometimes. In most cases this was a NullPointerException. A workaround in H2 has been implemented. The root cause of the problem is now documented in the FAQ: Tomcat sets all static fields (final or non-final) to null when unloading a web application. A workaround is to put the h2.jar in the lib directory, or set the system property org.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES to false.
@changelog_1209_h2
@changelog_1212_h2
#Version 1.1.107 (2009-01-24)
@changelog_1210_li
@changelog_1213_li
#Some DatabaseMetaData operations did not work for non-admin users for versions 1.1.x.
@changelog_1211_li
@changelog_1214_li
#The MySQL compatibility extension fromUnixTime now used the English locale.
@changelog_1212_li
@changelog_1215_li
#When using LOG=2 and repeatedly updating the last row rows of a table, the index file grew quickly.
@changelog_1213_li
@changelog_1216_li
#In versions 1.1.105 and 1.1.106, encrypted script files of earlier versions could not be processed. This is now again possible. The problem was that such script files were stored in a special format (STORAGE=TEXT) but support for this format was removed in version 1.1.105.
@changelog_1214_li
@changelog_1217_li
#Enabling the trace mechanism by creating a specially named file is no longer supported.
@changelog_1215_h2
@changelog_1218_h2
#Version 1.1.106 (2009-01-04)
@changelog_1216_li
@changelog_1219_li
#Statement.setQueryTimeout did not work correctly for some statements.
@changelog_1217_li
@changelog_1220_li
#CREATE DOMAIN: built-in data types can now only be changed if no tables exist.
@changelog_1218_li
@changelog_1221_li
#Linked tables: a workaround for Oracle DATE columns has been implemented.
@changelog_1219_li
@changelog_1222_li
#DatabaseMetaData.getPrimaryKeys: the column PK_NAME now contains the constraint name instead of the index name (compatibility for PostgreSQL and Derby).
@changelog_1220_li
@changelog_1223_li
#Using IN(..) inside a IN(SELECT..) did not always work.
@changelog_1221_li
@changelog_1224_li
#Views with IN(..) that used a view itself did not work.
@changelog_1222_li
@changelog_1225_li
#Union queries with LIMIT or ORDER BY that are used in a view or subquery did not work.
@changelog_1223_li
@changelog_1226_li
#The license change a bit: so far the license was modified to say 'Swiss law'. This is now changed back to the original 'US law'. This was requested by a user, and I don't see a problem.
@changelog_1224_li
@changelog_1227_li
#Constraints for local temporary tables now session scoped. So far they were global. Thanks a lot to Eric Faulhaber for finding and fixing this problem!
@changelog_1225_li
@changelog_1228_li
#When using the auto-server mode, and if the lock file was modified in the future, the wrong exception was thrown ('Connection is broken' instead of 'Error opening database: lock file modified in the future').
@changelog_1226_h2
@changelog_1229_h2
#Version 1.1.105 (2008-12-19)
@changelog_1227_li
@changelog_1230_li
#The setting STORAGE=TEXT is no longer supported.
@changelog_1228_li
@changelog_1231_li
#Deleting a database using the tool DeleteDbFiles deleted LOB files of other databases in the same directory.
@changelog_1229_li
@changelog_1232_li
#When used in a subquery, LIKE and IN(..) did not work correctly sometimes.
@changelog_1230_li
@changelog_1233_li
#The fulltext search documentation has been improved.
@changelog_1231_li
@changelog_1234_li
#ARRAY_GET returned the wrong data type (ARRAY). Now it returns VARCHAR.
@changelog_1232_li
@changelog_1235_li
#Natural join: the joined columns are not repeated any more when using SELECT *.
@changelog_1233_li
@changelog_1236_li
#User defined aggregate functions: the method getType expected internal data types instead of SQL types.
@changelog_1234_li
@changelog_1237_li
#User defined aggregate functions did not work if there was no group by expression.
@changelog_1235_li
@changelog_1238_li
#MySQL compatibility: support for := assignment as in @sum:=@sum+x
@changelog_1236_li
@changelog_1239_li
#INSERT INTO TEST(SELECT * FROM TEST) is now supported.
@changelog_1237_li
@changelog_1240_li
#Each session threw an invisible exception when garbage collected.
@changelog_1238_li
@changelog_1241_li
#Foreign key constraints that refer to a quoted column did not work.
@changelog_1239_li
@changelog_1242_li
#New meta data column INFORMATION_SCHEMA.TABLES.LAST_MODIFICATION to get the table modification counter.
@changelog_1240_li
@changelog_1243_li
#Shell: line comments didn't work correctly.
@changelog_1241_li
@changelog_1244_li
#H2 Console: columns are now listed for up to 500 tables instead of 100.
@changelog_1242_li
@changelog_1245_li
#H2 Console: Cmd+Enter executes the current statement, Alt+Space for autocomplete.
@changelog_1243_li
@changelog_1246_li
#JaQu: the maximum length of a column can now be defined using maxLength. For an example, see Product.java (maxLength(category, 255)).
@changelog_1244_li
@changelog_1247_li
#Rıdvan Ağar has completed the Turkish translation of the H2 Console. Thanks a lot!
@changelog_1245_h2
@changelog_1248_h2
#Version 1.1.104 (2008-11-28)
@changelog_1246_li
@changelog_1249_li
#If a query that was used like a table contained group by and was ordered by an expression that is not in the column list, an exception was thrown.
@changelog_1247_li
@changelog_1250_li
#JaQu: tables are now auto-created when running a query.
@changelog_1248_li
@changelog_1251_li
#The optimizer had problems with function tables (for example CSVREAD and FTL_SEARCH). A new system property h2.estimatedFunctionTableRows (default 1000) defines how many rows can be expected in the table.
@changelog_1249_li
@changelog_1252_li
#The function SUM could overflow when using large values. It returns now a data type that is safe.
@changelog_1250_li
@changelog_1253_li
#The function AVG could overflow when using large values. Fixed.
@changelog_1251_li
@changelog_1254_li
#The emergency reserve file has been removed. It didn't provide an appropriate solution for the problem. It is still possible for an application to detect and deal with the low disk space problem (deleting temporary files for example) using DatabaseEventListener.diskSpaceIsLow, but this method is now always called with stillAvailable=0.
@changelog_1252_li
@changelog_1255_li
#Build: JAVA_HOME is now automatically detected on Mac OS X.
@changelog_1253_li
@changelog_1256_li
#Testing for local connections was very slow on some systems.
@changelog_1254_li
@changelog_1257_li
#The cache memory usage calculation is more conservative.
@changelog_1255_li
@changelog_1258_li
#Allocating space got slower and slower the larger the database.
@changelog_1256_li
@changelog_1259_li
#ALTER TABLE ALTER COLUMN could throw the wrong exception in the last version (Table not found).
@changelog_1257_li
@changelog_1260_li
#Updatable result sets: the key columns can now be updated.
@changelog_1258_li
@changelog_1261_li
#The H2DatabaseProvider for ActiveObjects is now included in the tools section.
@changelog_1259_li
@changelog_1262_li
#The H2Platform for Oracle Toplink Essential has been improved a bit.
@changelog_1260_li
@changelog_1263_li
#The Windows service to start H2 didn't work in version 1.1.
@changelog_1261_li
@changelog_1264_li
#File systems with a maximum file size (for example FAT) are now supported using the file prefix 'split:'. In this case the files are split in parts of 1 GB. Example URL: jdbc:h2:split:~/db/test. If you want to split into parts of 1 MB, use jdbc:h2:split:20:~/db/test (the part size is 1 << x, the default is 30 meaning 1 GB).
@changelog_1262_li
@changelog_1265_li
#The database now tries to detect if the classloader or virtual machine has almost shut down by checking if static final variables are set to null. This should help reduce exceptions when stopping the web application.
@changelog_1263_li
@changelog_1266_li
#Compatibility for MS SQL Server DATEDIFF(YYYY, .., ..)
@changelog_1264_li
@changelog_1267_li
#ResultSet.getObject for CLOB or BLOB will return a java.sql.Clob / java.sql.Blob object instead of a java.io.Reader / java.io.InputStream as in version 1.0. This behavior can be changed using the system property h2.returnLobObjects (true by default for version 1.1).
@changelog_1265_li
@changelog_1268_li
#The interface CloseListener has a new method 'remove' that is called when the trigger is dropped.
@changelog_1266_li
@changelog_1269_li
#Fulltext search: there was a memory leak when creating and dropping fulltext indexes in a loop.
@changelog_1267_h2
@changelog_1270_h2
#Version 1.1.103 (2008-11-07)
@changelog_1268_li
@changelog_1271_li
#Could not order by a formula when the formula was in the group by list but not in the select list.
@changelog_1269_li
@changelog_1272_li
#Date values that match the daylight saving time end were not allowed in times zones were the daylight saving time ends at midnight, for years larger than 2037. Example: timezone Brasilia, date 2042-10-12. This is a problem of Java, however a workaround is implemented in H2 that solves most problems (except the problems of java.util.Date itself).
@changelog_1270_li
@changelog_1273_li
#ALTER TABLE used a lot of memory when using multi-version concurrency.
@changelog_1271_li
@changelog_1274_li
#Referential integrity for in-memory databases didn't work in some cases in version 1.1.102.
@changelog_1272_li
@changelog_1275_li
#New column INFORMATION_SCHEMA.COLUMNS.SEQUENCE_NAME to get the name of the sequence for auto-increment columns.
@changelog_1273_li
@changelog_1276_li
#Aliases for built-in data types (such as MEDIUMBLOB which is an alias for BLOB) can now be re-mapped to another data type using CREATE DOMAIN. However main built-in data types (such as INTEGER) can not be re-mapped.
@changelog_1274_li
@changelog_1277_li
#The Japanese translation has been completed by Masahiro Ikemoto. Thanks a lot!
@changelog_1275_li
@changelog_1278_li
#Improved PostgreSQL compatibility for NEXTVAL and CURRVAL.
@changelog_1276_li
@changelog_1279_li
#Less heap memory is needed when multiple databases are open at the same time: the memory reserve (used to rollback after out of memory) is now global and no longer allocated for each database separately.
@changelog_1277_li
@changelog_1280_li
#New system property h2.browser to set the browser to use.
@changelog_1278_li
@changelog_1281_li
#To start the browser, java.awt.Desktop.browse is now used if available.
@changelog_1279_h2
@changelog_1282_h2
#Version 1.1.102 (2008-10-24)
@changelog_1280_li
@changelog_1283_li
#The French translation of the H2 Console has been improved by Olivier Parent. Thanks a lot!
@changelog_1281_li
@changelog_1284_li
#There was a memory leak when creating and dropping tables and indexes in a loop (persistent database only).
@changelog_1282_li
@changelog_1285_li
#SET LOG 2 was not effective if executed after opening the database.
@changelog_1283_li
@changelog_1286_li
#Translating the H2 Console is now simpler.
@changelog_1284_li
@changelog_1287_li
#Common exception (error code 23*) are no longer written to the .trace.db file by default.
@changelog_1285_li
@changelog_1288_li
#In-memory databases don't write LOBs to files any longer.
@changelog_1286_li
@changelog_1289_li
#Self referencing constraints didn't restrict deleting rows that reference itself if there is another row that references it.
@changelog_1287_li
@changelog_1290_li
#ResultSetMetaData.getColumnName now returns the alias name except for columns.
@changelog_1288_li
@changelog_1291_li
#Temporary files are now deleted when the database is closed, even if they were not garbage collected so far.
@changelog_1289_h2
@changelog_1292_h2
#Version 1.1.101 (2008-10-17)
@changelog_1290_li
@changelog_1293_li
#Errors with code 42000 - 42999 are no longer written to the trace file by default.
@changelog_1291_li
@changelog_1294_li
#Queries with more than 10 tables are now faster.
@changelog_1292_li
@changelog_1295_li
#Opening a connection with AUTO_SERVER=TRUE is now fast when the database is already open in another process (less than 0.01 seconds instead of 2 seconds).
@changelog_1293_li
@changelog_1296_li
#IF [NOT] EXISTS is supported for named constraints in ALTER TABLE ... ADD/DROP CONSTRAINT.
@changelog_1294_li
@changelog_1297_li
#The error messages have been translated to Spanish by Dario V. Fassi. Thanks a lot!
@changelog_1295_li
@changelog_1298_li
#Linked tables: the automatic connection sharing didn't work. Actually the system property h2.shareLinkedConnections was working in the opposite direction: it was disabled when set to true. Now it works as expected.
@changelog_1296_li
@changelog_1299_li
#Opening large database is now faster.
@changelog_1297_li
@changelog_1300_li
#New system property h2.socketConnectTimeout, the timeout in milliseconds to connect to a server. The default is 2000 (2 seconds).
@changelog_1298_li
@changelog_1301_li
#The wrong parameters were bound to subqueries with parameters, specially when using IN(SELECT ...) and IN(...).
@changelog_1299_li
@changelog_1302_li
#Unset parameters were not detected when the query was re-compiled.
@changelog_1300_li
@changelog_1303_li
#New functions ISO_YEAR, ISO_WEEK, ISO_DAY_OF_WEEK. Thanks a lot to Robert Rathsack for implementing those!
@changelog_1301_li
@changelog_1304_li
#The date functions DAYOFYEAR, DAYOFMONTH, DAYOFWEEK are now called DAY_OF_YEAR, DAY_OF_MONTH, DAY_OF_WEEK (the old names still work).
@changelog_1302_li
@changelog_1305_li
#An out of memory error while deleting or updating many rows could result in a strange exception.
@changelog_1303_li
@changelog_1306_li
#Linked tables: compatibility with MS SQL Server has been improved.
@changelog_1304_li
@changelog_1307_li
#Renaming tables that have foreign keys with cascade didn't work correctly.
@changelog_1305_li
@changelog_1308_li
#The auto-reconnect feature didn't work when using the auto-server mode. Fixed.
@changelog_1306_li
@changelog_1309_li
#Fulltext search: new method FT_DROP_INDEX.
@changelog_1307_li
@changelog_1310_li
#The optimization to group using an index didn't work in some cases in version 1.1 (see also system property h2.optimizeGroupSorted).
@changelog_1308_li
@changelog_1311_li
#OSGi meta data is included in the manifest file. An OSGi BundleActivator is included: it loads the database driver when starting the bundle, and unloads it when stopping the bundle.
@changelog_1309_li
@changelog_1312_li
#The default value for MAX_MEMORY_UNDO is now 50000.
@changelog_1310_li
@changelog_1313_li
#For alias columns, ResultSetMetaData.getTableName() and getColumnName() now return the real table and column name in the default mode.
@changelog_1311_li
@changelog_1314_li
#In SQL scripts created with SCRIPT TO, schemas are now only created if they don't exist yet.
@changelog_1312_li
@changelog_1315_li
#After re-connecting to a database, the database event listener (if set) is informed about it.
@changelog_1313_li
@changelog_1316_li
#Local temporary tables now support indexes. Thanks a lot to Matt Roy!
@changelog_1314_li
@changelog_1317_li
#RUNSCRIPT no longer uses a temporary file.
@changelog_1315_li
@changelog_1318_li
#New system table INFORMATION_SCHEMA.SESSION_STATE containing the SQL statements that make up the session state. The list currently contains variables (SET @..) and local temporary tables (without data).
@changelog_1316_li
@changelog_1319_li
#After an automatic re-connect, part of the session state stays (the part that is stored in the SESSION_STATE table).
@changelog_1317_li
@changelog_1320_li
#The build didn't work if the directory temp didn't exist before.
@changelog_1318_li
@changelog_1321_li
#New system property h2.maxReconnect (default 3) to limit the number of re-connects for the same SQL statement (this is usually only important for SHUTDOWN).
@changelog_1319_li
@changelog_1322_li
#WHERE .. IN (SELECT ...) could throw a NullPointerException.
@changelog_1320_li
@changelog_1323_li
#Improved Glassfish / Toplink support in H2Platform thanks to Marcio Borges from Brazil. Thanks a lot!
@changelog_1321_h2
@changelog_1324_h2
#Version 1.1.100 (2008-10-04)
@changelog_1322_li
@changelog_1325_li
#In version 1.1, the following system properties are now enabled by default: h2.lobFilesInDirectories, h2.optimizeGroupSorted, h2.optimizeInJoin, h2.shareLinkedConnections
@changelog_1323_li
@changelog_1326_li
#The H2 Console tool now works with the JDBC-ODBC bridge.
@changelog_1324_li
@changelog_1327_li
#The H2 Console tool now supports command line options to start things separately.
@changelog_1325_li
@changelog_1328_li
#Large objects did not work for in-memory databases in server mode in Linux.
@changelog_1326_li
@changelog_1329_li
#Connections from a local address other than 'localhost' were not allowed if remote connections were disabled. This was always a problem, but only got visible in the last release because the server no longer connects to 'localhost' if networked.
@changelog_1327_li
@changelog_1330_li
#The h2console.war can now be built using the Java build.
@changelog_1328_li
@changelog_1331_li
#By default, databases are shared in the same process. For read-only databases this causes unnecessary synchronization, but safes memory. If you want that each connection opens its own database, append ;OPEN_NEW=TRUE to the database URL.
@changelog_1329_li
@changelog_1332_li
#New auto-reconnect feature will cause the JDBC driver to reconnect to the database if the connection is lost. To enable, append ;AUTO_RECONNECT=TRUE to the database URL. This is specially helpful when using AUTO_SERVER. AUTO_SERVER automatically uses auto-reconnect.
@changelog_1330_li
@changelog_1333_li
#CreateCluster: the property 'serverlist' is now called 'serverList'.
@changelog_1331_li
@changelog_1334_li
#The ConvertTraceFile tool could not parse some files because the trace mechanism did not encode prepared statement parameters.
@changelog_1332_li
@changelog_1335_li
#Databases names can now be one character long (the minimum size used to be 2 characters).
@changelog_1333_h2
@changelog_1336_h2
#Version 1.0.79 (2008-09-26)
@changelog_1334_li
@changelog_1337_li
#Linked tables that point to the same database can now share the connection within the same database. Access to the same connection is serialized. To enable this feature, set the system property h2.shareLinkedConnections to true.
@changelog_1335_li
@changelog_1338_li
#Multiple processes can now access the same database without having to explicitly start the server. To do that, append ;AUTO_SERVER=TRUE to the database URL. In this case, the server is started automatically if the connection is in embedded mode, and the server mode is used if a server is running. If the process that opened the first connection is closed, the other client need to reconnect (there is no automatic re-connect so far). Remote connections are allowed, but only to this database.
@changelog_1336_li
@changelog_1339_li
#The server tool now displays the correct IP address if networked.
@changelog_1337_li
@changelog_1340_li
#Can now start a TCP server with port 0 (automatically select a port).
@changelog_1338_li
@changelog_1341_li
#Result sets with just a unique index can now be updated (previously a primary key was required).
@changelog_1339_li
@changelog_1342_li
#LINKED TABLE: the schema name can now be set. When multiple tables exist in different schema, and the schema name is not set, an exception is thrown.
@changelog_1340_li
@changelog_1343_li
#LINKED TABLE: worked around a bug in Oracle with the CHAR data type.
@changelog_1341_li
@changelog_1344_li
#Faster hash code calculation for large binary arrays.
@changelog_1342_li
@changelog_1345_li
#Faster storage re-use algorithm thanks to Greg Dhuse from cleversafe.com.
@changelog_1343_li
@changelog_1346_li
#The database supports the SHOW command for better MySQL and PostgreSQL compatibility.
@changelog_1344_li
@changelog_1347_li
#The H2 Console now abbreviates large texts in results.
@changelog_1345_li
@changelog_1348_li
#Multiple UNION queries could not be used in derived tables.
@changelog_1346_li
@changelog_1349_li
#Linked tables can now be read-only.
@changelog_1347_li
@changelog_1350_li
#Temporary linked tables are now supported.
@changelog_1348_li
@changelog_1351_li
#It was possible to create tables in read-only databases.
@changelog_1349_li
@changelog_1352_li
#SET SCHEMA_SEARCH_PATH is now documented.
@changelog_1350_li
@changelog_1353_li
#SET SCHEMA did not work for views.
@changelog_1351_li
@changelog_1354_li
#Row level locking for MVCC is now enabled. The exception 'Concurrent update in table ...' is still thrown, but only after the lock timeout.
@changelog_1352_li
@changelog_1355_li
#The maximum log file size setting was ignored for large databases.
@changelog_1353_li
@changelog_1356_li
#Multi-Version Concurrency (MVCC) may no longer be used when using the multi-threaded kernel feature (MULTI_THREADED). An exception is thrown when trying to connect with both settings. Additional synchronization is required before those features can be used together.
@changelog_1354_li
@changelog_1357_li
#The data type JAVA_OBJECT could not be used in updatable result sets.
@changelog_1355_li
@changelog_1358_li
#The system property h2.optimizeInJoin did not work correctly.
@changelog_1356_li
@changelog_1359_li
#Conditions such as ID=? AND ID < ? were slow.
@changelog_1357_h2
@changelog_1360_h2
#Version 1.0.78 (2008-08-28)
@changelog_1358_li
@changelog_1361_li
#The documentation no longer uses a frameset (except the Javadocs).
@changelog_1359_li
@changelog_1362_li
#When using DB_CLOSE_DELAY, sometimes a NullPointerException is thrown when the database is opened almost at the same time as it is closed automatically. Thanks a lot to Dmitry Pekar for finding this!
@changelog_1360_li
@changelog_1363_li
#Java methods with variable number of parameters can now be used (for Java 1.5 or newer).
@changelog_1361_li
@changelog_1364_li
#The Japanese translation has been improved by Masahiro Ikemoto. Thanks a lot!
@changelog_1362_li
@changelog_1365_li
#The H2 Console replaced an empty user name with a single space.
@changelog_1363_li
@changelog_1366_li
#The build target 'build jarSmall' now includes the embedded database.
@changelog_1364_li
@changelog_1367_li
#JdbcDataSource now keeps the password in a char array where possible.
@changelog_1365_li
@changelog_1368_li
#ResultSet.absolute did not always work with large result sets.
@changelog_1366_li
@changelog_1369_li
#Column aliases can now be used in GROUP BY and HAVING.
@changelog_1367_li
@changelog_1370_li
#Jason Brittain has contributed MySQL date functions. Thanks a lot! They are not in the h2.jar file currently, but in src/tools/org/h2/mode/FunctionsMySQL.java. To install, add this class to the classpath and call FunctionsMySQL.register(conn) in the Java code.
@changelog_1368_h2
@changelog_1371_h2
#Version 1.0.77 (2008-08-16)
@changelog_1369_li
@changelog_1372_li
#JaQu is now using prepared statements and supports Date, Time, Timestamp.
@changelog_1370_li
@changelog_1373_li
#When using remote in-memory databases, large LOB objects did not work.
@changelog_1371_li
@changelog_1374_li
#Timestamp columns such as TIMESTAMP(6) were not compatible to other database.
@changelog_1372_li
@changelog_1375_li
#Opening a large database was slow if there was a problem opening the previous time.
@changelog_1373_li
@changelog_1376_li
#NOT IN(SELECT ...) was incorrect if the subquery returns no rows.
@changelog_1374_li
@changelog_1377_li
#CREATE TABLE AS SELECT did not work correctly in the multi-version concurrency mode.
@changelog_1375_li
@changelog_1378_li
#Support a comma before closing a list, as in: create table test(id int,)
@changelog_1376_li
@changelog_1379_li
#MySQL compatibility: linked tables had lower case column names on some systems.
@changelog_1377_li
@changelog_1380_li
#DB2 compatibility: the DB2 fetch-first-clause is supported.
@changelog_1378_li
@changelog_1381_li
#Oracle compatibility: old style outer join syntax using (+) did work correctly sometimes.
@changelog_1379_li
@changelog_1382_li
#ResultSet.setFetchSize is now supported.
@changelog_1380_li
@changelog_1383_li
#It has been reported that when using Install4j on some Linux systems and enabling the 'pack200' option, the h2.jar becomes corrupted by the install process, causing application failure. A workaround is to add an empty file h2.jar.nopack next to the h2.jar file. The reason for this problem is not known.
@changelog_1381_h2
@changelog_1384_h2
#Version 1.0.76 (2008-07-27)
@changelog_1382_li
@changelog_1385_li
#The comment of a domain (user defined data type) is now used as the default column comment when creating a column with this domain.
@changelog_1383_li
@changelog_1386_li
#Invalid database names are now detected and a better error message is thrown.
@changelog_1384_li
@changelog_1387_li
#ResultSetMetaData.getColumnClassName now returns the correct class name for BLOB and CLOB.
@changelog_1385_li
@changelog_1388_li
#Fixed the Oracle mode: Oracle allows multiple rows only where all columns of the unique index are NULL.
@changelog_1386_li
@changelog_1389_li
#There is a problem with Hibernate when using Boolean columns. A patch for Hibernate has been submitted at http://opensource.atlassian.com/projects/hibernate/browse/HHH-3401
@changelog_1387_li
@changelog_1390_li
#ORDER BY on tableName.columnName didn't work correctly if the column name was also used as an alias.
@changelog_1388_li
@changelog_1391_li
#H2 Console: the progress display when opening a database has been improved.
@changelog_1389_li
@changelog_1392_li
#The error message when the server doesn't start has been improved.
@changelog_1390_li
@changelog_1393_li
#Key values can now be changed in updatable result sets.
@changelog_1391_li
@changelog_1394_li
#Changes in updatable result sets are now visible even when resetting the result set.
@changelog_1392_li
@changelog_1395_li
#Temporary files were sometimes deleted too late when executing large insert, update, or delete operations.
@changelog_1393_li
@changelog_1396_li
#The database file was growing after deleting many rows, and after large update operations.
@cheatSheet_1000_h1
...
...
@@ -2711,162 +2720,174 @@ F A Q
# Why is Opening my Database Slow?
@faq_1010_a
# Is the GCJ Version Stable? Faster?
# Column Names are Incorrect?
@faq_1011_a
# Is the GCJ Version Stable? Faster?
@faq_1012_a
# How to Translate this Project?
@faq_1012_h3
@faq_1013_h3
#Are there Known Bugs? When is the Next Release?
@faq_1013_p
@faq_1014_p
# Usually, bugs get fixes as they are found. There is a release every few weeks. Here is the list of known and confirmed issues:
@faq_1014_li
@faq_1015_li
#Tomcat and Glassfish 3 set most static fields (final or non-final) to <code>null</code> when unloading a web application. This can cause a <code>NullPointerException</code> in H2 versions 1.1.107 and older, and may still not work in newer versions. Please report it if you run into this issue. In Tomcat >= 6.0 this behavior can be disabled by setting the system property <code>org.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES=false</code>, however Tomcat may then run out of memory. A known workaround is to put the <code>h2*.jar</code> file in a shared <code>lib</code> directory (<code>common/lib</code>).
@faq_1015_li
@faq_1016_li
#Some problems have been found with right outer join. Internally, it is converted to left outer join, which does not always produce the same results as other databases when used in combination with other joins.
@faq_1016_li
@faq_1017_li
#When using Install4j before 4.1.4 on Linux and enabling <code>pack200</code>, the <code>h2*.jar</code> becomes corrupted by the install process, causing application failure. A workaround is to add an empty file <code>h2*.jar.nopack</code> next to the <code>h2*.jar</code> file. This problem is solved in Install4j 4.1.4.
@faq_1017_h3
@faq_1018_h3
このデータベースエンジンはオープンソースですか？
@faq_1018_p
@faq_1019_p
# Yes. It is free to use and distribute, and the source code is included. See also under license.
@faq_1019_h3
@faq_1020_h3
#My Query is Slow
@faq_1020_p
@faq_1021_p
# Slow <code>SELECT</code> (or <code>DELETE, UPDATE, MERGE</code>) statement can have multiple reasons. Follow this checklist:
@faq_1021_li
@faq_1022_li
#Run <code>ANALYZE</code> (see documentation for details).
@faq_1022_li
@faq_1023_li
#Run the query with <code>EXPLAIN</code> and check if indexes are used (see documentation for details).
@faq_1023_li
@faq_1024_li
#If required, create additional indexes and try again using <code>ANALYZE</code> and <code>EXPLAIN</code>.
@faq_1024_li
@faq_1025_li
#If it doesn't help please report the problem.
@faq_1025_h3
@faq_1026_h3
新規データベースの構築方法は？
@faq_1026_p
@faq_1027_p
# By default, a new database is automatically created if it does not yet exist. See <a href="tutorial.html#creating_new_databases">Creating New Databases</a>.
@faq_1027_h3
@faq_1028_h3
データベースへの接続方法は？
@faq_1028_p
@faq_1029_p
# The database driver is <code>org.h2.Driver</code>, and the database URL starts with <code>jdbc:h2:</code>. To connect to a database using JDBC, use the following code:
@faq_1029_h3
@faq_1030_h3
データベースのファイルはどこに保存されますか？
@faq_1030_p
@faq_1031_p
# When using database URLs like <code>jdbc:h2:~/test</code>, the database is stored in the user directory. For Windows, this is usually <code>C:\Documents and Settings\<userName></code>. If the base directory is not set (as in <code>jdbc:h2:test</code>), the database files are stored in the directory where the application is started (the current working directory). When using the H2 Console application from the start menu, this is <code><Installation Directory>/bin</code>. The base directory can be set in the database URL. A fixed or relative path can be used. When using the URL <code>jdbc:h2:file:data/sample</code>, the database is stored in the directory <code>data</code> (relative to the current working directory). The directory is created automatically if it does not yet exist. It is also possible to use the fully qualified directory name (and for Windows, drive name). Example: <code>jdbc:h2:file:C:/data/test</code>
@faq_1031_h3
@faq_1032_h3
#What is the Size Limit (Maximum Size) of a Database?
@faq_1032_p
@faq_1033_p
# See <a href="advanced.html#limits_limitations">Limits and Limitations</a>.
@faq_1033_h3
@faq_1034_h3
これは信頼できるデータベースですか？
@faq_1034_p
@faq_1035_p
# That is not easy to say. It is still a quite new product. A lot of tests have been written, and the code coverage of these tests is very high. Randomized stress tests are run regularly. But there are probably still bugs that have not yet been found (as with most software). Some features are known to be dangerous, they are only supported for situations where performance is more important than reliability. Those dangerous features are:
@faq_1035_li
@faq_1036_li
#Disabling the transaction log mechanism using <code>SET LOG 0</code>.
@faq_1036_li
@faq_1037_li
#Using the transaction isolation level <code>READ_UNCOMMITTED</code> (<code>LOCK_MODE 0</code>) while at the same time using multiple connections.
@faq_1037_li
@faq_1038_li
#Disabling database file protection using <code>FILE_LOCK=NO</code> in the database URL.
@faq_1038_li
@faq_1039_li
#Disabling referential integrity using <code>SET REFERENTIAL_INTEGRITY FALSE</code>.
@faq_1039_p
@faq_1040_p
# In addition to that, running out of memory should be avoided. In older versions, OutOfMemory errors while using the database could corrupt a databases.
@faq_1040_p
@faq_1041_p
# Areas that are not fully tested:
@faq_1041_li
@faq_1042_li
#Platforms other than Windows XP, Linux, Mac OS X, or JVMs other than Sun 1.5 or 1.6
@faq_1042_li
@faq_1043_li
#The features <code>AUTO_SERVER</code> and <code>AUTO_RECONNECT</code>
@faq_1043_li
@faq_1044_li
#The MVCC (multi version concurrency) mode
@faq_1044_li
@faq_1045_li
#Cluster mode, 2-phase commit, savepoints
@faq_1045_li
@faq_1046_li
#24/7 operation
@faq_1046_li
@faq_1047_li
#Some operations on databases larger than 500 MB may be slower than expected
@faq_1047_li
@faq_1048_li
#The optimizer may not always select the best plan
@faq_1048_li
@faq_1049_li
#Fulltext search
@faq_1049_li
@faq_1050_li
#Operations on LOBs over 2 GB
@faq_1050_p
@faq_1051_p
# Areas considered experimental are:
@faq_1051_li
@faq_1052_li
#The PostgreSQL server
@faq_1052_li
@faq_1053_li
#Multi-threading within the engine using <code>SET MULTI_THREADED=1</code>
@faq_1053_li
@faq_1054_li
#Compatibility modes for other databases (only some features are implemented)
@faq_1054_p
@faq_1055_p
# Some users have reported that after a power failure, the database can sometimes not be opened because the index file is corrupt. In that case, the index file can be deleted (it is automatically re-created). To avoid this, append <code>;LOG=2</code> to the database URL. See also: <a href="grammar.html#set_log" class="notranslate">SET LOG</a>. This problem will be solved using the new 'page store' mechanism (currently beta).
@faq_1055_h3
@faq_1056_h3
#Column Names are Incorrect?
@faq_1057_p
# For the query <code>SELECT ID AS X FROM TEST</code> the method <code>ResultSetMetaData.getColumnName()</code> returns <code>ID</code>, I expect it to return <code>X</code>. What's wrong?
@faq_1058_p
# This is not a bug. According the the JDBC specification, the method <code>ResultSetMetaData.getColumnName()</code> should return the name of the column and not the alias name. If you need the alias name, use <a href="http://java.sun.com/javase/6/docs/api/java/sql/ResultSetMetaData.html#getColumnLabel(int)"><code>ResultSetMetaData.getColumnLabel()</code></a>. Other database don't work like this (they don't follow the JDBC standard). If you need compatibility with those databases, use the <a href="features.html#compatibility">Compatibility Mode</a>, or set the system property <a href="../javadoc/org/h2/constant/SysProperties.html#h2.aliasColumnName"><code>h2.aliasColumnName</code></a>.
@faq_1059_h3
#Why is Opening my Database Slow?
@faq_1056_p
@faq_1060_p
# If it takes a long time to open a database, in most cases it was not closed the last time. This is specially a problem for larger databases. To close a database, close all connections to it before the application ends, or execute the command <code>SHUTDOWN</code>. The database is also closed when the virtual machine exits normally by using a shutdown hook. However killing a Java process or calling <code>Runtime.halt</code> will prevent this. The reason why opening is slow in this situations is that indexes are re-created. If you can not guarantee the database is closed, consider using <a href="grammar.html#set_log" class="notranslate">SET LOG 2</a>.
@faq_1057_p
@faq_1061_p
# To find out what the problem is, open the database in embedded mode using the H2 Console. This will print progress information. If you have many lines with 'Creating index' it is an indication that the database was not closed the last time.
@faq_1058_p
@faq_1062_p
# Other possible reasons are: the database is very big (many GB), or contains linked tables that are slow to open.
@faq_1059_h3
@faq_1063_h3
#Is the GCJ Version Stable? Faster?
@faq_1060_p
@faq_1064_p
# The GCJ version is not as stable as the Java version. When running the regression test with the GCJ version, sometimes the application just stops at what seems to be a random point without error message. Currently, the GCJ version is also slower than when using the Sun VM. However, the startup of the GCJ version is faster than when using a VM.
@faq_1061_h3
@faq_1065_h3
このプロジェクトの翻訳方法は？
@faq_1062_p
@faq_1066_p
# For more information, see <a href="build.html#translating">Build/Translating</a>.
@features_1000_h1
...
...
@@ -4697,79 +4718,79 @@ SimpleResultSetを使用する
# To get information about page reads and writes, and the current caching algorithm in use, call <code>SELECT * FROM INFORMATION_SCHEMA.SETTINGS</code>. The number of pages read / written is listed for the data and index file.
