org.h2.engine

Class SysProperties

java.lang.Object

org.h2.engine.SysProperties

public class SysProperties
extends java.lang.Object

The constants defined in this class are initialized from system properties. Some system properties are per machine settings, and others are as a last resort and temporary solution to work around a problem in the application or database engine. Also, there are system properties to enable features that are not yet fully tested or that are not backward compatible.

System properties can be set when starting the virtual machine:

 java -Dh2.baseDir=/temp
 

They can be set within the application, but this must be done before loading any classes of this database (before loading the JDBC driver):

 System.setProperty("h2.baseDir", "/temp");
 

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	ALLOWED_CLASSES System property h2.allowedClasses (default: *). Comma separated list of class names or prefixes.
static boolean	BIG_DECIMAL_IS_DECIMAL System property h2.bigDecimalIsDecimal, true by default.
static java.lang.String	BIND_ADDRESS System property h2.bindAddress (default: null). The bind address to use.
static boolean	CHECK System property h2.check (default: true). Assertions in the database engine.
static boolean	CHECK2 System property h2.check2 (default: false). Additional assertions in the database engine.
static java.lang.String	CLIENT_TRACE_DIRECTORY System property h2.clientTraceDirectory (default: trace.db/). Directory where the trace files of the JDBC client are stored (only for client / server).
static int	COLLATOR_CACHE_SIZE System property h2.collatorCacheSize (default: 32000). The cache size for collation keys (in elements).
static int	CONSOLE_MAX_PROCEDURES_LIST_COLUMNS System property h2.consoleProcedureColumns (default: 500). Up to this many procedures, the column names are listed.
static int	CONSOLE_MAX_TABLES_LIST_COLUMNS System property h2.consoleTableColumns (default: 500). Up to this many tables, the column names are listed.
static int	CONSOLE_MAX_TABLES_LIST_INDEXES System property h2.consoleTableIndexes (default: 100). Up to this many tables, the column type and indexes are listed.
static boolean	CONSOLE_STREAM System property h2.consoleStream (default: true). H2 Console: stream query results.
static int	CONSOLE_TIMEOUT System property h2.consoleTimeout (default: 1800000). H2 Console: session timeout in milliseconds.
static java.lang.String	CUSTOM_DATA_TYPES_HANDLER System property h2.customDataTypesHandler (default: null). The CustomDataTypesHandler class name that is used to provide support for user defined custom data types.
static int	DATASOURCE_TRACE_LEVEL System property h2.dataSourceTraceLevel (default: 1). The trace level of the data source implementation.
static int	DELAY_WRONG_PASSWORD_MAX System property h2.delayWrongPasswordMax (default: 4000). The maximum delay in milliseconds before an exception is thrown for using the wrong user name or password.
static int	DELAY_WRONG_PASSWORD_MIN System property h2.delayWrongPasswordMin (default: 250). The minimum delay in milliseconds before an exception is thrown for using the wrong user name or password.
static boolean	ENABLE_ANONYMOUS_TLS System property h2.enableAnonymousTLS (default: true). When using TLS connection, the anonymous cipher suites should be enabled.
static java.lang.String	FILE_ENCODING System property file.encoding (default: Cp1252). It is usually set by the system and is the default encoding used for the RunScript and CSV tool.
static java.lang.String	FILE_SEPARATOR System property file.separator (default: /). It is usually set by the system, and used to build absolute file names.
static java.lang.String	H2_BROWSER INTERNAL
static java.lang.String	H2_SCRIPT_DIRECTORY INTERNAL
static boolean	IMPLICIT_RELATIVE_PATH System property h2.implicitRelativePath (default: true for version 1.3, false for version 1.4). If disabled, relative paths in database URLs need to be written as jdbc:h2:./test instead of jdbc:h2:test.
static java.lang.String	JAVA_OBJECT_SERIALIZER System property h2.javaObjectSerializer (default: null). The JavaObjectSerializer class name for java objects being stored in column of type OTHER.
static boolean	JAVA_SYSTEM_COMPILER System property h2.javaSystemCompiler (default: true). Whether to use the Java system compiler (ToolProvider.getSystemJavaCompiler()) if it is available to compile user defined functions.
static java.lang.String	LINE_SEPARATOR System property line.separator (default: \n). It is usually set by the system, and used by the script and trace tools.
static int	LOB_CLIENT_MAX_SIZE_MEMORY System property h2.lobClientMaxSizeMemory (default: 1048576). The maximum size of a LOB object to keep in memory on the client side when using the server mode.
static int	LOB_FILES_PER_DIRECTORY System property h2.lobFilesPerDirectory (default: 256). Maximum number of LOB files per directory.
static boolean	lobCloseBetweenReads System property h2.lobCloseBetweenReads (default: false). Close LOB files between read operations.
static int	MAX_FILE_RETRY System property h2.maxFileRetry (default: 16). Number of times to retry file delete and rename.
static int	MAX_MEMORY_ROWS System property h2.maxMemoryRows (default: 40000 per GB of available RAM). The default maximum number of rows to be kept in memory in a result set.
static int	MAX_RECONNECT System property h2.maxReconnect (default: 3). The maximum number of tries to reconnect in a row.
static long	MAX_TRACE_DATA_LENGTH System property h2.maxTraceDataLength (default: 65535). The maximum size of a LOB value that is written as data to the trace system.
static boolean	MODIFY_ON_WRITE System property h2.modifyOnWrite (default: false). Only modify the database file when recovery is necessary, or when writing to the database.
static boolean	NIO_CLEANER_HACK System property h2.nioCleanerHack (default: false). If enabled, use the reflection hack to un-map the mapped file if possible.
static boolean	NIO_LOAD_MAPPED System property h2.nioLoadMapped (default: false). If the mapped buffer should be loaded when the file is opened.
static boolean	OBJECT_CACHE System property h2.objectCache (default: true). Cache commonly used values (numbers, strings).
static int	OBJECT_CACHE_MAX_PER_ELEMENT_SIZE System property h2.objectCacheMaxPerElementSize (default: 4096). The maximum size (precision) of an object in the cache.
static int	OBJECT_CACHE_SIZE System property h2.objectCacheSize (default: 1024). The maximum number of objects in the cache.
static boolean	OLD_RESULT_SET_GET_OBJECT System property h2.oldResultSetGetObject, true by default.
static boolean	OLD_STYLE_OUTER_JOIN System property h2.oldStyleOuterJoin (default: true for version 1.3, false for version 1.4). Limited support for the old-style Oracle outer join with "(+)".
static java.lang.String	PG_DEFAULT_CLIENT_ENCODING System property h2.pgClientEncoding (default: UTF-8). Default client encoding for PG server.
static java.lang.String	PREFIX_TEMP_FILE System property h2.prefixTempFile (default: h2.temp). The prefix for temporary files in the temp directory.
static boolean	serializeJavaObject System property h2.serializeJavaObject (default: true). If true, values of type OTHER will be stored in serialized form and have the semantics of binary data for all operations (such as sorting and conversion to string).
static int	SERVER_CACHED_OBJECTS System property h2.serverCachedObjects (default: 64). TCP Server: number of cached objects per session.
static int	SERVER_RESULT_SET_FETCH_SIZE System property h2.serverResultSetFetchSize (default: 100). The default result set fetch size when using the server mode.
static int	SOCKET_CONNECT_RETRY System property h2.socketConnectRetry (default: 16). The number of times to retry opening a socket.
static int	SOCKET_CONNECT_TIMEOUT System property h2.socketConnectTimeout (default: 2000). The timeout in milliseconds to connect to a server.
static boolean	SORT_BINARY_UNSIGNED System property h2.sortBinaryUnsigned (default: false with version 1.3, true with version 1.4). Whether binary data should be sorted in unsigned mode (0xff is larger than 0x00).
static boolean	SORT_NULLS_HIGH System property h2.sortNullsHigh (default: false). Invert the default sorting behavior for NULL, such that NULL is at the end of a result set in an ascending sort and at the beginning of a result set in a descending sort.
static long	SPLIT_FILE_SIZE_SHIFT System property h2.splitFileSizeShift (default: 30). The maximum file size of a split file is 1L << x.
static java.lang.String	SYNC_METHOD System property h2.syncMethod (default: sync). What method to call when closing the database, on checkpoint, and on CHECKPOINT SYNC.
static boolean	THREAD_DEADLOCK_DETECTOR System property h2.threadDeadlockDetector (default: false). Detect thread deadlocks in a background thread.
static boolean	TRACE_IO System property h2.traceIO (default: false). Trace all I/O operations.
static boolean	UNLIMITED_TIME_RANGE System property h2.unlimitedTimeRange, false by default.
static java.lang.String	URL_MAP System property h2.urlMap (default: null). A properties file that contains a mapping between database URLs.
static boolean	USE_THREAD_CONTEXT_CLASS_LOADER System property h2.useThreadContextClassLoader (default: false). Instead of using the default class loader when deserializing objects, the current thread-context class loader will be used.
static java.lang.String	USER_HOME System property user.home (empty string if not set). It is usually set by the system, and used as a replacement for ~ in file names.

Method Summary

Methods

Modifier and Type	Method and Description
static java.lang.String	getBaseDir() INTERNAL
static java.lang.String	getScriptDirectory() System property h2.scriptDirectory (default: empty string). Relative or absolute directory where the script files are stored to or read from.
static void	setBaseDir(java.lang.String dir) INTERNAL

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

H2_SCRIPT_DIRECTORY

public static final java.lang.String H2_SCRIPT_DIRECTORY

INTERNAL

See Also:

Constant Field Values

H2_BROWSER

public static final java.lang.String H2_BROWSER

INTERNAL

See Also:

Constant Field Values

FILE_ENCODING

public static final java.lang.String FILE_ENCODING

System property file.encoding (default: Cp1252).
It is usually set by the system and is the default encoding used for the RunScript and CSV tool.

FILE_SEPARATOR

public static final java.lang.String FILE_SEPARATOR

System property file.separator (default: /).
It is usually set by the system, and used to build absolute file names.

LINE_SEPARATOR

public static final java.lang.String LINE_SEPARATOR

System property line.separator (default: \n).
It is usually set by the system, and used by the script and trace tools.

USER_HOME

public static final java.lang.String USER_HOME

System property user.home (empty string if not set).
It is usually set by the system, and used as a replacement for ~ in file names.

ALLOWED_CLASSES

public static final java.lang.String ALLOWED_CLASSES

System property h2.allowedClasses (default: *).
Comma separated list of class names or prefixes.

ENABLE_ANONYMOUS_TLS

public static final boolean ENABLE_ANONYMOUS_TLS

System property h2.enableAnonymousTLS (default: true).
When using TLS connection, the anonymous cipher suites should be enabled.

BIND_ADDRESS

public static final java.lang.String BIND_ADDRESS

System property h2.bindAddress (default: null).
The bind address to use.

CHECK

public static final boolean CHECK

System property h2.check (default: true).
Assertions in the database engine.

CHECK2

public static final boolean CHECK2

System property h2.check2 (default: false).
Additional assertions in the database engine.

CLIENT_TRACE_DIRECTORY

public static final java.lang.String CLIENT_TRACE_DIRECTORY

System property h2.clientTraceDirectory (default: trace.db/).
Directory where the trace files of the JDBC client are stored (only for client / server).

COLLATOR_CACHE_SIZE

public static final int COLLATOR_CACHE_SIZE

System property h2.collatorCacheSize (default: 32000).
The cache size for collation keys (in elements). Used when a collator has been set for the database.

CONSOLE_MAX_TABLES_LIST_INDEXES

public static final int CONSOLE_MAX_TABLES_LIST_INDEXES

System property h2.consoleTableIndexes (default: 100).
Up to this many tables, the column type and indexes are listed.

CONSOLE_MAX_TABLES_LIST_COLUMNS

public static final int CONSOLE_MAX_TABLES_LIST_COLUMNS

System property h2.consoleTableColumns (default: 500).
Up to this many tables, the column names are listed.

CONSOLE_MAX_PROCEDURES_LIST_COLUMNS

public static final int CONSOLE_MAX_PROCEDURES_LIST_COLUMNS

System property h2.consoleProcedureColumns (default: 500).
Up to this many procedures, the column names are listed.

CONSOLE_STREAM

public static final boolean CONSOLE_STREAM

System property h2.consoleStream (default: true).
H2 Console: stream query results.

CONSOLE_TIMEOUT

public static final int CONSOLE_TIMEOUT

System property h2.consoleTimeout (default: 1800000).
H2 Console: session timeout in milliseconds. The default is 30 minutes.

DATASOURCE_TRACE_LEVEL

public static final int DATASOURCE_TRACE_LEVEL

System property h2.dataSourceTraceLevel (default: 1).
The trace level of the data source implementation. Default is 1 for error.

DELAY_WRONG_PASSWORD_MIN

public static final int DELAY_WRONG_PASSWORD_MIN

System property h2.delayWrongPasswordMin (default: 250).
The minimum delay in milliseconds before an exception is thrown for using the wrong user name or password. This slows down brute force attacks. The delay is reset to this value after a successful login. Unsuccessful logins will double the time until DELAY_WRONG_PASSWORD_MAX. To disable the delay, set this system property to 0.

DELAY_WRONG_PASSWORD_MAX

public static final int DELAY_WRONG_PASSWORD_MAX

System property h2.delayWrongPasswordMax (default: 4000).
The maximum delay in milliseconds before an exception is thrown for using the wrong user name or password. This slows down brute force attacks. The delay is reset after a successful login. The value 0 means there is no maximum delay.

JAVA_SYSTEM_COMPILER

public static final boolean JAVA_SYSTEM_COMPILER

System property h2.javaSystemCompiler (default: true).
Whether to use the Java system compiler (ToolProvider.getSystemJavaCompiler()) if it is available to compile user defined functions. If disabled or if the system compiler is not available, the com.sun.tools.javac compiler is used if available, and "javac" (as an external process) is used if not.

lobCloseBetweenReads

public static boolean lobCloseBetweenReads

System property h2.lobCloseBetweenReads (default: false).
Close LOB files between read operations.

LOB_FILES_PER_DIRECTORY

public static final int LOB_FILES_PER_DIRECTORY

System property h2.lobFilesPerDirectory (default: 256).
Maximum number of LOB files per directory.

LOB_CLIENT_MAX_SIZE_MEMORY

public static final int LOB_CLIENT_MAX_SIZE_MEMORY

System property h2.lobClientMaxSizeMemory (default: 1048576).
The maximum size of a LOB object to keep in memory on the client side when using the server mode.

MAX_FILE_RETRY

public static final int MAX_FILE_RETRY

System property h2.maxFileRetry (default: 16).
Number of times to retry file delete and rename. in Windows, files can't be deleted if they are open. Waiting a bit can help (sometimes the Windows Explorer opens the files for a short time) may help. Sometimes, running garbage collection may close files if the user forgot to call Connection.close() or InputStream.close().

MAX_RECONNECT

public static final int MAX_RECONNECT

System property h2.maxReconnect (default: 3).
The maximum number of tries to reconnect in a row.

MAX_MEMORY_ROWS

public static final int MAX_MEMORY_ROWS

System property h2.maxMemoryRows (default: 40000 per GB of available RAM).
The default maximum number of rows to be kept in memory in a result set.

MAX_TRACE_DATA_LENGTH

public static final long MAX_TRACE_DATA_LENGTH

System property h2.maxTraceDataLength (default: 65535).
The maximum size of a LOB value that is written as data to the trace system.

MODIFY_ON_WRITE

public static final boolean MODIFY_ON_WRITE

System property h2.modifyOnWrite (default: false).
Only modify the database file when recovery is necessary, or when writing to the database. If disabled, opening the database always writes to the file (except if the database is read-only). When enabled, the serialized file lock is faster.

NIO_LOAD_MAPPED

public static final boolean NIO_LOAD_MAPPED

System property h2.nioLoadMapped (default: false).
If the mapped buffer should be loaded when the file is opened. This can improve performance.

NIO_CLEANER_HACK

public static final boolean NIO_CLEANER_HACK

System property h2.nioCleanerHack (default: false).
If enabled, use the reflection hack to un-map the mapped file if possible. If disabled, System.gc() is called in a loop until the object is garbage collected. See also http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4724038

OBJECT_CACHE

public static final boolean OBJECT_CACHE

System property h2.objectCache (default: true).
Cache commonly used values (numbers, strings). There is a shared cache for all values.

OBJECT_CACHE_MAX_PER_ELEMENT_SIZE

public static final int OBJECT_CACHE_MAX_PER_ELEMENT_SIZE

System property h2.objectCacheMaxPerElementSize (default: 4096).
The maximum size (precision) of an object in the cache.

OBJECT_CACHE_SIZE

public static final int OBJECT_CACHE_SIZE

System property h2.objectCacheSize (default: 1024).
The maximum number of objects in the cache. This value must be a power of 2.

OLD_STYLE_OUTER_JOIN

public static final boolean OLD_STYLE_OUTER_JOIN

System property h2.oldStyleOuterJoin (default: true for version 1.3, false for version 1.4).
Limited support for the old-style Oracle outer join with "(+)".

OLD_RESULT_SET_GET_OBJECT

public static final boolean OLD_RESULT_SET_GET_OBJECT

System property h2.oldResultSetGetObject, true by default. Return Byte and Short instead of Integer from ResultSet#getObject(...) for TINYINT and SMALLINT values.

BIG_DECIMAL_IS_DECIMAL

public static final boolean BIG_DECIMAL_IS_DECIMAL

System property h2.bigDecimalIsDecimal, true by default. If true map BigDecimal to DECIMAL type, if false map it to NUMERIC as specified in JDBC specification (see Mapping from Java Object Types to JDBC Types).

UNLIMITED_TIME_RANGE

public static final boolean UNLIMITED_TIME_RANGE

System property h2.unlimitedTimeRange, false by default.

Controls limits of TIME data type.

h2.unlimitedTimeRange	Minimum TIME value	Maximum TIME value
false	00:00:00.000000000	23:59:59.999999999
true	-2562047:47:16.854775808	2562047:47:16.854775807

PG_DEFAULT_CLIENT_ENCODING

public static final java.lang.String PG_DEFAULT_CLIENT_ENCODING

System property h2.pgClientEncoding (default: UTF-8).
Default client encoding for PG server. It is used if the client does not sends his encoding.

PREFIX_TEMP_FILE

public static final java.lang.String PREFIX_TEMP_FILE

System property h2.prefixTempFile (default: h2.temp).
The prefix for temporary files in the temp directory.

SERVER_CACHED_OBJECTS

public static final int SERVER_CACHED_OBJECTS

System property h2.serverCachedObjects (default: 64).
TCP Server: number of cached objects per session.

SERVER_RESULT_SET_FETCH_SIZE

public static final int SERVER_RESULT_SET_FETCH_SIZE

System property h2.serverResultSetFetchSize (default: 100).
The default result set fetch size when using the server mode.

SOCKET_CONNECT_RETRY

public static final int SOCKET_CONNECT_RETRY

System property h2.socketConnectRetry (default: 16).
The number of times to retry opening a socket. Windows sometimes fails to open a socket, see bug http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6213296

SOCKET_CONNECT_TIMEOUT

public static final int SOCKET_CONNECT_TIMEOUT

System property h2.socketConnectTimeout (default: 2000).
The timeout in milliseconds to connect to a server.

SORT_BINARY_UNSIGNED

public static final boolean SORT_BINARY_UNSIGNED

System property h2.sortBinaryUnsigned (default: false with version 1.3, true with version 1.4).
Whether binary data should be sorted in unsigned mode (0xff is larger than 0x00).

SORT_NULLS_HIGH

public static final boolean SORT_NULLS_HIGH

System property h2.sortNullsHigh (default: false).
Invert the default sorting behavior for NULL, such that NULL is at the end of a result set in an ascending sort and at the beginning of a result set in a descending sort.

SPLIT_FILE_SIZE_SHIFT

public static final long SPLIT_FILE_SIZE_SHIFT

System property h2.splitFileSizeShift (default: 30).
The maximum file size of a split file is 1L << x.

SYNC_METHOD

public static final java.lang.String SYNC_METHOD

System property h2.syncMethod (default: sync).
What method to call when closing the database, on checkpoint, and on CHECKPOINT SYNC. The following options are supported: "sync" (default): RandomAccessFile.getFD().sync(); "force": RandomAccessFile.getChannel().force(true); "forceFalse": RandomAccessFile.getChannel().force(false); "": do not call a method (fast but there is a risk of data loss on power failure).

TRACE_IO

public static final boolean TRACE_IO

System property h2.traceIO (default: false).
Trace all I/O operations.

THREAD_DEADLOCK_DETECTOR

public static final boolean THREAD_DEADLOCK_DETECTOR

System property h2.threadDeadlockDetector (default: false).
Detect thread deadlocks in a background thread.

IMPLICIT_RELATIVE_PATH

public static final boolean IMPLICIT_RELATIVE_PATH

System property h2.implicitRelativePath (default: true for version 1.3, false for version 1.4).
If disabled, relative paths in database URLs need to be written as jdbc:h2:./test instead of jdbc:h2:test.

URL_MAP

public static final java.lang.String URL_MAP

System property h2.urlMap (default: null).
A properties file that contains a mapping between database URLs. New connections are written into the file. An empty value in the map means no redirection is used for the given URL.

USE_THREAD_CONTEXT_CLASS_LOADER

public static final boolean USE_THREAD_CONTEXT_CLASS_LOADER

System property h2.useThreadContextClassLoader (default: false).
Instead of using the default class loader when deserializing objects, the current thread-context class loader will be used.

serializeJavaObject

public static boolean serializeJavaObject

System property h2.serializeJavaObject (default: true).
If true, values of type OTHER will be stored in serialized form and have the semantics of binary data for all operations (such as sorting and conversion to string).
If false, the objects will be serialized only for I/O operations and a few other special cases (for example when someone tries to get the value in binary form or when comparing objects that are not comparable otherwise).
If the object implements the Comparable interface, the method compareTo will be used for sorting (but only if objects being compared have a common comparable super type). Otherwise the objects will be compared by type, and if they are the same by hashCode, and if the hash codes are equal, but objects are not, the serialized forms (the byte arrays) are compared.
The string representation of the values use the toString method of object.
In client-server mode, the server must have all required classes in the class path. On the client side, this setting is required to be disabled as well, to have correct string representation and display size.
In embedded mode, no data copying occurs, so the user has to make defensive copy himself before storing, or ensure that the value object is immutable.

JAVA_OBJECT_SERIALIZER

public static final java.lang.String JAVA_OBJECT_SERIALIZER

System property h2.javaObjectSerializer (default: null).
The JavaObjectSerializer class name for java objects being stored in column of type OTHER. It must be the same on client and server to work correctly.

CUSTOM_DATA_TYPES_HANDLER

public static final java.lang.String CUSTOM_DATA_TYPES_HANDLER

System property h2.customDataTypesHandler (default: null).
The CustomDataTypesHandler class name that is used to provide support for user defined custom data types. It must be the same on client and server to work correctly.

Method Detail

setBaseDir

public static void setBaseDir(java.lang.String dir)

INTERNAL

getBaseDir

public static java.lang.String getBaseDir()

INTERNAL

getScriptDirectory

public static java.lang.String getScriptDirectory()

System property h2.scriptDirectory (default: empty string).
Relative or absolute directory where the script files are stored to or read from.

Returns:

the current value