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: *).
static java.lang.String	AUTH_CONFIG_FILE System property h2.authConfigFile (default: null).
static java.lang.String	BIND_ADDRESS System property h2.bindAddress (default: null).
static boolean	CHECK System property h2.check (default: true for JDK/JRE, false for Android).
static java.lang.String	CLIENT_TRACE_DIRECTORY System property h2.clientTraceDirectory (default: trace.db/).
static int	COLLATOR_CACHE_SIZE System property h2.collatorCacheSize (default: 3 2000).
static int	CONSOLE_MAX_PROCEDURES_LIST_COLUMNS System property h2.consoleProcedureColumns (default: 500).
static int	CONSOLE_MAX_TABLES_LIST_COLUMNS System property h2.consoleTableColumns (default: 500).
static int	CONSOLE_MAX_TABLES_LIST_INDEXES System property h2.consoleTableIndexes (default: 100).
static boolean	CONSOLE_STREAM System property h2.consoleStream (default: true).
static int	CONSOLE_TIMEOUT System property h2.consoleTimeout (default: 1800000).
static int	DATASOURCE_TRACE_LEVEL System property h2.dataSourceTraceLevel (default: 1).
static int	DELAY_WRONG_PASSWORD_MAX System property h2.delayWrongPasswordMax (default: 4000).
static int	DELAY_WRONG_PASSWORD_MIN System property h2.delayWrongPasswordMin (default: 250).
static boolean	ENABLE_ANONYMOUS_TLS System property h2.enableAnonymousTLS (default: true).
static boolean	FORCE_AUTOCOMMIT_OFF_ON_COMMIT System property h2.forceAutoCommitOffOnCommit (default: false).
static java.lang.String	H2_BROWSER INTERNAL
static java.lang.String	H2_SCRIPT_DIRECTORY INTERNAL
static java.lang.String	JAVA_OBJECT_SERIALIZER System property h2.javaObjectSerializer (default: null).
static boolean	JAVA_SYSTEM_COMPILER System property h2.javaSystemCompiler (default: true).
static int	LOB_CLIENT_MAX_SIZE_MEMORY System property h2.lobClientMaxSizeMemory (default: 1048576).
static boolean	lobCloseBetweenReads System property h2.lobCloseBetweenReads (default: false).
static int	MAX_FILE_RETRY System property h2.maxFileRetry (default: 16).
static int	MAX_MEMORY_ROWS System property h2.maxMemoryRows (default: 40000 per GB of available RAM).
static int	MAX_RECONNECT System property h2.maxReconnect (default: 3).
static long	MAX_TRACE_DATA_LENGTH System property h2.maxTraceDataLength (default: 65535).
static boolean	NIO_CLEANER_HACK System property h2.nioCleanerHack (default: false).
static boolean	NIO_LOAD_MAPPED System property h2.nioLoadMapped (default: false).
static boolean	OBJECT_CACHE System property h2.objectCache (default: true).
static int	OBJECT_CACHE_MAX_PER_ELEMENT_SIZE System property h2.objectCacheMaxPerElementSize (default: 4096).
static int	OBJECT_CACHE_SIZE System property h2.objectCacheSize (default: 1024).
static java.lang.String	PG_DEFAULT_CLIENT_ENCODING System property h2.pgClientEncoding (default: UTF-8).
static java.lang.String	PREFIX_TEMP_FILE System property h2.prefixTempFile (default: h2.temp).
static int	SERVER_CACHED_OBJECTS System property h2.serverCachedObjects (default: 64).
static int	SERVER_RESULT_SET_FETCH_SIZE System property h2.serverResultSetFetchSize (default: 100).
static int	SOCKET_CONNECT_RETRY System property h2.socketConnectRetry (default: 16).
static int	SOCKET_CONNECT_TIMEOUT System property h2.socketConnectTimeout (default: 2000).
static long	SPLIT_FILE_SIZE_SHIFT System property h2.splitFileSizeShift (default: 30).
static boolean	THREAD_DEADLOCK_DETECTOR System property h2.threadDeadlockDetector (default: false).
static boolean	TRACE_IO System property h2.traceIO (default: false).
static java.lang.String	URL_MAP System property h2.urlMap (default: null).
static boolean	USE_THREAD_CONTEXT_CLASS_LOADER System property h2.useThreadContextClassLoader (default: false).
static java.lang.String	USER_HOME System property user.home (empty string if not set).

Method Summary

Modifier and Type	Method and Description
static java.lang.String	getBaseDir() INTERNAL
static java.lang.String	getScriptDirectory() System property h2.scriptDirectory (default: empty string).
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

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 for JDK/JRE, false for Android). Optional additional checks 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: 3 2000). 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_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.

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 https://bugs.openjdk.java.net/browse/JDK-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.

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.

FORCE_AUTOCOMMIT_OFF_ON_COMMIT

public static boolean FORCE_AUTOCOMMIT_OFF_ON_COMMIT

System property h2.forceAutoCommitOffOnCommit (default: false). Throw error if transaction's auto-commit property is true when a commit is executed.

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 https://bugs.openjdk.java.net/browse/JDK-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.

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.

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.

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.

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.

AUTH_CONFIG_FILE

public static final java.lang.String AUTH_CONFIG_FILE

System property h2.authConfigFile (default: null). authConfigFile define the URL of configuration file of DefaultAuthenticator

Method Detail

setBaseDir

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

INTERNAL

Parameters:

dir - base directory

getBaseDir

public static java.lang.String getBaseDir()

INTERNAL

Returns:

base directory

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