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com.sleepycat.db
Class EnvironmentConfig

java.lang.Object
  com.sleepycat.db.EnvironmentConfig

All Implemented Interfaces:

Cloneable

public class EnvironmentConfig

extends Object

implements Cloneable

Specifies the attributes of an environment.

To change the default settings for a database environment, an application creates a configuration object, customizes settings and uses it for environment construction. The set methods of this class validate the configuration values when the method is invoked. An IllegalArgumentException is thrown if the value is not valid for that attribute.

All commonly used environment attributes have convenience setter/getter methods defined in this class. For example, to change the default transaction timeout setting for an environment, the application should do the following:

    // customize an environment configuration
    EnvironmentConfig envConfig = new EnvironmentConfig();
    envConfig.setTxnTimeout(10000);  // will throw if timeout value is invalid
    // Open the environment.
    Environment myEnvironment = new Environment(home, envConfig);

Additional parameters are described in the example.properties file found at the top level of the distribution package. These additional parameters will not be needed by most applications. This category of properties can be specified for the EnvironmentConfig object through a Properties object read by EnvironmentConfig(Properties), or individually through EnvironmentConfig.setConfigParam().

For example, an application can change the default btree node size with:

    envConfig.setConfigParam("je.nodeMaxEntries", "256");

Environment configuration follows this order of precedence:

1. Configuration parameters specified in <environment home>/je.properties take first precedence.
2. Configuration parameters set in the EnvironmentConfig object used at Environment construction are next.
3. Any configuration parameters not set by the application are set to system defaults, described in the example.properties file.

An EnvironmentConfig can be used to specify both mutable and immutable environment properties. Immutable properties may be specified when the first Environment handle (instance) is opened for a given physical environment. When more handles are opened for the same environment, the following rules apply:

1. Immutable properties must equal the original values specified when constructing an Environment handle for an already open environment. When a mismatch occurs, an exception is thrown.
2. Mutable properties are ignored when constructing an Environment handle for an already open environment.

After an Environment has been constructed, it's mutable properties may be changed using Environment.setConfig(com.sleepycat.db.EnvironmentConfig).

Field Summary

static EnvironmentConfig

DEFAULT

Constructor Summary

EnvironmentConfig()
Create an EnvironmentConfig initialized with the system default settings.

Method Summary

void	addDataDir(File dataDir) Set the path of a directory to be used as the location of the access method database files.
boolean	getAllowCreate() Return true if the database environment is configured to create any underlying files, as necessary.
int	getCacheCount() Return the number of shared memory buffer pools, that is, the number of caches.
long	getCacheSize() Return the size of the shared memory buffer pool, that is, the cache.
boolean	getCDBLockAllDatabases() Return true if the Concurrent Data Store applications are configured to perform locking on an environment-wide basis rather than on a per-database basis.
File[]	getDataDirs() Return the array of data directories.
boolean	getDirectDatabaseIO() Return true if the database environment has been configured to not buffer database files.
boolean	getDirectLogIO() Return true if the database environment has been configured to not buffer log files.
boolean	getDsyncDatabases() Return true if the database environment has been configured to flush database writes to the backing disk before returning from the write system call.
boolean	getDsyncLog() Return true if the database environment has been configured to flush log writes to the backing disk before returning from the write system call.
boolean	getEncrypted() Return the database environment has been configured to perform encryption.
ErrorHandler	getErrorHandler() Return the function to be called if an error occurs.
String	getErrorPrefix() Return the prefix string that appears before error messages.
OutputStream	getErrorStream() Return the an OutputStream for displaying error messages.
FeedbackHandler	getFeedbackHandler() Return the object's methods to be called to provide feedback.
boolean	getInitializeCache() Return true if the database environment is configured with a shared memory buffer pool.
boolean	getInitializeCDB() Return true if the database environment is configured for the Concurrent Data Store product.
boolean	getInitializeLocking() Return true if the database environment is configured for locking.
boolean	getInitializeLogging() Return true if the database environment is configured for logging.
boolean	getInitializeRegions() Return true if the database environment has been configured to page-fault shared regions into memory when initially creating or joining a database environment.
boolean	getInitializeReplication() Return true if the database environment is configured for replication.
boolean	getJoinEnvironment() Return the handle is configured to join an existing environment.
byte[][]	getLockConflicts() Return the locking conflicts matrix.
LockDetectMode	getLockDetectMode() Return true if the deadlock detector is configured to run whenever a lock conflict occurs.
boolean	getLockDown() Return true if the database environment is configured to lock shared environment files and memory-mapped databases into memory.
long	getLockTimeout() Return the database environment lock timeout value, in microseconds; a timeout of 0 means no timeout is set.
boolean	getLogAutoRemove() Return true if the system has been configured to to automatically remove log files that are no longer needed.
int	getLogBufferSize() Return the size of the in-memory log buffer, in bytes.
File	getLogDirectory() Return the path of a directory to be used as the location of logging files.
int	getLogFileMode() Return the absolute file mode for created log files.
boolean	getLogInMemory() Return true if the database environment is configured to maintain transaction logs in memory rather than on disk.
LogRecordHandler	getLogRecordHandler() Return the handler for application-specific log records.
int	getLogRegionSize() Return the size of the underlying logging subsystem region.
int	getMaxLockers() Return the maximum number of lockers.
int	getMaxLockObjects() Return the maximum number of locked objects.
int	getMaxLocks() Return the maximum number of locks.
int	getMaxLogFileSize() Return the maximum size of a single file in the log, in bytes.
int	getMaxMutexes() Return the total number of mutexes allocated.
int	getMaxOpenFiles() Return the maximum number of file descriptors that will be opened concurrently..
int	getMaxWrite() Return the maximum number of sequential write operations.
int	getMaxWriteSleep() Return the microseconds to pause before scheduling further write operations.
MessageHandler	getMessageHandler() Return the function to be called with an informational message.
OutputStream	getMessageStream() Return the an OutputStream for displaying informational messages.
long	getMMapSize() Return the maximum file size, in bytes, for a file to be mapped into the process address space.
long	getMode() Return the mode to use when creating underlying files and shared memory segments.
int	getMutexAlignment() Return the mutex alignment, in bytes.
int	getMutexIncrement() Return the number of additional mutexes to allocate.
int	getMutexTestAndSetSpins() Return the test-and-set spin count.
boolean	getNoLocking() Return true if the system has been configured to grant all requested mutual exclusion mutexes and database locks without regard for their actual availability.
boolean	getNoMMap() Return true if the system has been configured to copy read-only database files into the local cache instead of potentially mapping them into process memory.
boolean	getNoPanic() Return true if the system has been configured to ignore any panic state in the database environment.
boolean	getOverwrite() Return true if the system has been configured to overwrite files stored in encrypted formats before deleting them.
PanicHandler	getPanicHandler() Return the function to be called if the database environment panics.
boolean	getPrivate() Return true if the database environment is configured to only be accessed by a single process.
boolean	getRegister() Return true if the check for process failure when the environment is opened.
long	getReplicationLimit() Return the transmit limit in bytes for a single call to Environment.processReplicationMessage.
ReplicationTransport	getReplicationTransport() Return the replication callback function used to transmit data using the replication application's communication infrastructure.
boolean	getRunFatalRecovery() Return the handle is configured to run catastrophic recovery on the database environment before opening it for use.
boolean	getRunRecovery() Return the handle is configured to run normal recovery on the database environment before opening it for use.
long	getSegmentId() Return the base segment ID.
boolean	getSystemMemory() Return true if the database environment is configured to allocate memory from system shared memory instead of from memory backed by the filesystem.
File	getTemporaryDirectory() Return the path of a directory to be used as the location of temporary files.
int	getTestAndSetSpins() Return the number of times test-and-set mutexes should spin before blocking.
boolean	getThreaded() Return true if the handle is configured to be free-threaded.
boolean	getTransactional() Return true if the database environment is configured for transactions.
int	getTxnMaxActive() Return the minimum number of simultaneously active transactions supported by the database environment.
boolean	getTxnNoSync() Return true if the system has been configured to not write or synchronously flush the log on transaction commit.
boolean	getTxnNotDurable() Return true if the system has been configured to not write log records.
long	getTxnTimeout() Return the database environment transaction timeout value, in microseconds; a timeout of 0 means no timeout is set.
Date	getTxnTimestamp() Return the time to which recovery will be done, or 0 if recovery will be done to the most current possible date.
boolean	getTxnWriteNoSync() Return true if the system has been configured to write, but not synchronously flush, the log on transaction commit.
boolean	getUseEnvironment() Return true if the database environment is configured to accept information from the process environment when naming files.
boolean	getUseEnvironmentRoot() Return true if the database environment is configured to accept information from the process environment when naming files if the process has appropriate permissions.
boolean	getVerboseDeadlock() Return if the database environment is configured to display additional information when doing deadlock detection.
boolean	getVerboseRecovery() Return if the database environment is configured to display additional information when performing recovery.
boolean	getVerboseRegister() Return if the database environment is configured to display additional information concerning support for the setRegister(boolean) method.
boolean	getVerboseReplication() Return if the database environment is configured to display additional information when processing replication messages.
boolean	getVerboseWaitsFor() Return if the database environment is configured to display the waits-for table when doing deadlock detection.
boolean	getYieldCPU() Return true if the system has been configured to yield the processor immediately after each page or mutex acquisition.
void	setAllowCreate(boolean allowCreate) Configure the database environment to create any underlying files, as necessary.
void	setCacheCount(int cacheCount) Set the number of shared memory buffer pools, that is, the number of caches.
void	setCacheSize(long cacheSize) Set the size of the shared memory buffer pool, that is, the size of the cache.
void	setCDBLockAllDatabases(boolean cdbLockAllDatabases) Configure Concurrent Data Store applications to perform locking on an environment-wide basis rather than on a per-database basis.
void	setDirectDatabaseIO(boolean directDatabaseIO) Configure the database environment to not buffer database files.
void	setDirectLogIO(boolean directLogIO) Configure the database environment to not buffer log files.
void	setDsyncDatabases(boolean dsyncDatabases) Configure the database environment to flush database writes to the backing disk before returning from the write system call, rather than flushing database writes explicitly in a separate system call, as necessary.
void	setDsyncLog(boolean dsyncLog) Configure the database environment to flush log writes to the backing disk before returning from the write system call, rather than flushing log writes explicitly in a separate system call.
void	setEncrypted(String password) Set the password used to perform encryption and decryption.
void	setErrorHandler(ErrorHandler errorHandler) Set the function to be called if an error occurs.
void	setErrorPrefix(String errorPrefix) Set the prefix string that appears before error messages.
void	setErrorStream(OutputStream errorStream) Set an OutputStream for displaying error messages.
void	setFeedbackHandler(FeedbackHandler feedbackHandler) Set an object whose methods are called to provide feedback.
void	setInitializeCache(boolean initializeCache) Configure a shared memory buffer pool in the database environment.
void	setInitializeCDB(boolean initializeCDB) Configure the database environment for the Concurrent Data Store product.
void	setInitializeLocking(boolean initializeLocking) Configure the database environment for locking.
void	setInitializeLogging(boolean initializeLogging) Configure the database environment for logging.
void	setInitializeRegions(boolean initializeRegions) Configure the database environment to page-fault shared regions into memory when initially creating or joining a database environment.
void	setInitializeReplication(boolean initializeReplication) Configure the database environment for replication.
void	setJoinEnvironment(boolean joinEnvironment) Configure the handle to join an existing environment.
void	setLockConflicts(byte[][] lockConflicts) Configure the locking conflicts matrix.
void	setLockDetectMode(LockDetectMode lockDetectMode) Configure if the deadlock detector is to be run whenever a lock conflict occurs.
void	setLockDown(boolean lockDown) Configure the database environment to lock shared environment files and memory-mapped databases into memory.
void	setLockTimeout(long lockTimeout) Set the timeout value for the database environment locks.
void	setLogAutoRemove(boolean logAutoRemove) Configure the system to automatically remove log files that are no longer needed.
void	setLogBufferSize(int logBufferSize) Set the size of the in-memory log buffer, in bytes.
void	setLogDirectory(File logDirectory) Set the path of a directory to be used as the location of logging files.
void	setLogFileMode(int mode) Set the absolute file mode for created log files.
void	setLogInMemory(boolean inmemory) If set, maintain transaction logs in memory rather than on disk.
void	setLogRecordHandler(LogRecordHandler logRecordHandler) Set a function to process application-specific log records.
void	setLogRegionSize(int logRegionSize) Set the size of the underlying logging area of the database environment, in bytes.
void	setMaxLockers(int maxLockers) Set the maximum number of locking entities supported by the database environment.
void	setMaxLockObjects(int maxLockObjects) Set the maximum number of locked objects supported by the database environment.
void	setMaxLocks(int maxLocks) Set the maximum number of locks supported by the database environment.
void	setMaxLogFileSize(int maxLogFileSize) Set the maximum size of a single file in the log, in bytes.
void	setMaxMutexes(int maxMutexes) Set the total number of mutexes to allocate.
void	setMaxOpenFiles(int maxOpenFiles) Limit the number of file descriptors the library will open concurrently when flushing dirty pages from the cache.
void	setMaxWrite(int maxWrite, int maxWriteSleep) Limit the number of sequential write operations scheduled by the library when flushing dirty pages from the cache.
void	setMessageHandler(MessageHandler messageHandler) Set a function to be called with an informational message.
void	setMessageStream(OutputStream messageStream) Set an OutputStream for displaying informational messages.
void	setMMapSize(long mmapSize) Set the maximum file size, in bytes, for a file to be mapped into the process address space.
void	setMode(int mode) Configure the database environment to use a specific mode when creating underlying files and shared memory segments.
void	setMutexAlignment(int mutexAlignment) Set the mutex alignment, in bytes.
void	setMutexIncrement(int mutexIncrement) Increase the number of mutexes to allocate.
void	setMutexTestAndSetSpins(int mutexTestAndSetSpins) Specify the number of times that test-and-set mutexes should spin without blocking.
void	setNoLocking(boolean noLocking) Configure the system to grant all requested mutual exclusion mutexes and database locks without regard for their actual availability.
void	setNoMMap(boolean noMMap) Configure the system to copy read-only database files into the local cache instead of potentially mapping them into process memory.
void	setNoPanic(boolean noPanic) Configure the system to ignore any panic state in the database environment.
void	setOverwrite(boolean overwrite) Configure the system to overwrite files stored in encrypted formats before deleting them.
void	setPanicHandler(PanicHandler panicHandler) Set the function to be called if the database environment panics.
void	setPrivate(boolean isPrivate) Configure the database environment to only be accessed by a single process (although that process may be multithreaded).
void	setRegister(boolean register) Check if a process has failed while using the database environment, that is, if a process has exited with an open Environment handle.
void	setReplicationLimit(long replicationLimit) Impose a byte-count limit on the amount of data that will be transmitted from a site in a single call to Environment.processReplicationMessage.
void	setReplicationTransport(int envid, ReplicationTransport replicationTransport) Initialize the communication infrastructure for a database environment participating in a replicated application.
void	setRPCServer(String rpcServer, long rpcClientTimeout, long rpcServerTimeout) Establish a connection to a RPC server for this database environment.
void	setRunFatalRecovery(boolean runFatalRecovery) Configure to run catastrophic recovery on this environment before opening it for normal use.
void	setRunRecovery(boolean runRecovery) Configure to run normal recovery on this environment before opening it for normal use.
void	setSegmentId(long segmentId) Specify a base segment ID for database environment shared memory regions created in system memory on VxWorks or systems supporting X/Open-style shared memory interfaces; for example, UNIX systems supporting shmget and related System V IPC interfaces.
void	setSystemMemory(boolean systemMemory) Configure the database environment to allocate memory from system shared memory instead of from memory backed by the filesystem.
void	setTemporaryDirectory(File temporaryDirectory) Set the path of a directory to be used as the location of temporary files.
void	setTestAndSetSpins(int testAndSetSpins) Set the number of times test-and-set mutexes should spin before blocking.
void	setThreaded(boolean threaded) Configure the handle to be free-threaded; that is, usable by multiple threads within a single address space.
void	setTransactional(boolean transactional) Configure the database environment for transactions.
void	setTxnMaxActive(int txnMaxActive) Configure the database environment to support at least txnMaxActive active transactions.
void	setTxnNoSync(boolean txnNoSync) Configure the system to not write or synchronously flush the log on transaction commit.
void	setTxnNotDurable(boolean txnNotDurable) Configure the system to not write log records.
void	setTxnTimeout(long txnTimeout) Set the timeout value for the database environment transactions.
void	setTxnTimestamp(Date txnTimestamp) Recover to the specified time rather than to the most current possible date.
void	setTxnWriteNoSync(boolean txnWriteNoSync) Configure the system to write, but not synchronously flush, the log on transaction commit.
void	setUseEnvironment(boolean useEnvironment) Configure the database environment to accept information from the process environment when naming files, regardless of the status of the process.
void	setUseEnvironmentRoot(boolean useEnvironmentRoot) Configure the database environment to accept information from the process environment when naming files, if the process has appropriate permissions (for example, users with a user-ID of 0 on UNIX systems).
void	setVerboseDeadlock(boolean verboseDeadlock) Display additional information when doing deadlock detection.
void	setVerboseRecovery(boolean verboseRecovery) Display additional information when performing recovery.
void	setVerboseRegister(boolean verboseRegister) Display additional information concerning support for the setRegister(boolean) method.
void	setVerboseReplication(boolean verboseReplication) Display additional information when processing replication messages.
void	setVerboseWaitsFor(boolean verboseWaitsFor) Display the waits-for table when doing deadlock detection.
void	setYieldCPU(boolean yieldCPU) Configure the system to yield the processor immediately after each page or mutex acquisition.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final EnvironmentConfig DEFAULT

Constructor Detail

EnvironmentConfig

public EnvironmentConfig()

Create an EnvironmentConfig initialized with the system default settings.

Method Detail

setTransactional

public void setTransactional(boolean transactional)

Configure the database environment for transactions.

This configuration option should be used when transactional guarantees such as atomicity of multiple operations and durability are important.

Parameters:

transactional - If true, configure the database environment for transactions.

getTransactional

public boolean getTransactional()

Return true if the database environment is configured for transactions.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured for transactions.

setAllowCreate

public void setAllowCreate(boolean allowCreate)

Configure the database environment to create any underlying files, as necessary.

Parameters:

allowCreate - If true, configure the database environment to create any underlying files, as necessary.

getAllowCreate

public boolean getAllowCreate()

Return true if the database environment is configured to create any underlying files, as necessary.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured to create any underlying files, as necessary.

setCacheSize

public void setCacheSize(long cacheSize)

Set the size of the shared memory buffer pool, that is, the size of the cache.

The cache should be the size of the normal working data set of the application, with some small amount of additional memory for unusual situations. (Note: the working set is not the same as the number of pages accessed simultaneously, and is usually much larger.)

The default cache size is 256KB, and may not be specified as less than 20KB. Any cache size less than 500MB is automatically increased by 25% to account for buffer pool overhead; cache sizes larger than 500MB are used as specified. The current maximum size of a single cache is 4GB. (All sizes are in powers-of-two, that is, 256KB is 2^18 not 256,000.)

The database environment's cache size may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_cachesize", one or more whitespace characters, and the cache size specified in three parts: the gigabytes of cache, the additional bytes of cache, and the number of caches, also separated by whitespace characters. For example, "set_cachesize 2 524288000 3" would create a 2.5GB logical cache, split between three physical caches. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

This method may be called at any time during the life of the application.

Parameters:

cacheSize - The size of the shared memory buffer pool, that is, the size of the cache.

Throws:

DatabaseException - if a failure occurs.

getCacheSize

public long getCacheSize()

Return the size of the shared memory buffer pool, that is, the cache.

This method may be called at any time during the life of the application.

Returns:

The size of the shared memory buffer pool, that is, the cache.

setCacheCount

public void setCacheCount(int cacheCount)

Set the number of shared memory buffer pools, that is, the number of caches.

It is possible to specify caches larger than 4GB and/or large enough they cannot be allocated contiguously on some architectures. For example, some releases of Solaris limit the amount of memory that may be allocated contiguously by a process. This method allows applications to break the cache broken up into a number of equally sized, separate pieces of memory.

The database environment's cache size may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_cachesize", one or more whitespace characters, and the cache size specified in three parts: the gigabytes of cache, the additional bytes of cache, and the number of caches, also separated by whitespace characters. For example, "set_cachesize 2 524288000 3" would create a 2.5GB logical cache, split between three physical caches. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

This method may be called at any time during the life of the application.

Parameters:

cacheCount - The number of shared memory buffer pools, that is, the number of caches.

Throws:

DatabaseException - if a failure occurs.

getCacheCount

public int getCacheCount()

Return the number of shared memory buffer pools, that is, the number of caches.

This method may be called at any time during the life of the application.

Returns:

The number of shared memory buffer pools, that is, the number of caches.

setCDBLockAllDatabases

public void setCDBLockAllDatabases(boolean cdbLockAllDatabases)

Configure Concurrent Data Store applications to perform locking on an environment-wide basis rather than on a per-database basis.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may not be called after the environment has been opened.

Parameters:

cdbLockAllDatabases - If true, configure Concurrent Data Store applications to perform locking on an environment-wide basis rather than on a per-database basis.

getCDBLockAllDatabases

public boolean getCDBLockAllDatabases()

Return true if the Concurrent Data Store applications are configured to perform locking on an environment-wide basis rather than on a per-database basis.

This method may be called at any time during the life of the application.

Returns:

True if the Concurrent Data Store applications are configured to perform locking on an environment-wide basis rather than on a per-database basis.

addDataDir

public void addDataDir(File dataDir)

Set the path of a directory to be used as the location of the access method database files.

Paths specified to Environment.openDatabase and Environment.openSecondaryDatabase will be searched relative to this path. Paths set using this method are additive, and specifying more than one will result in each specified directory being searched for database files. If any directories are specified, created database files will always be created in the first path specified.

If no database directories are specified, database files must be named either by absolute paths or relative to the environment home directory.

The database environment's data directories may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_data_dir", one or more whitespace characters, and the directory name.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may not be called after the environment has been opened. If joining an existing database environment, the information specified to this method must be consistent with the existing environment or corruption can occur.

Parameters:

dataDir - A directory to be used as a location for database files. On Windows platforms, this argument will be interpreted as a UTF-8 string, which is equivalent to ASCII for Latin characters.

getDataDirs

public File[] getDataDirs()

Return the array of data directories.

This method may be called at any time during the life of the application.

Returns:

The array of data directories.

setDirectDatabaseIO

public void setDirectDatabaseIO(boolean directDatabaseIO)

Configure the database environment to not buffer database files.

This is intended to avoid to avoid double caching.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

directDatabaseIO - If true, configure the database environment to not buffer database files.

getDirectDatabaseIO

public boolean getDirectDatabaseIO()

Return true if the database environment has been configured to not buffer database files.

This method may be called at any time during the life of the application.

Returns:

True if the database environment has been configured to not buffer database files.

setDirectLogIO

public void setDirectLogIO(boolean directLogIO)

Configure the database environment to not buffer log files.

This is intended to avoid to avoid double caching.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

directLogIO - If true, configure the database environment to not buffer log files.

getDirectLogIO

public boolean getDirectLogIO()

Return true if the database environment has been configured to not buffer log files.

This method may be called at any time during the life of the application.

Returns:

True if the database environment has been configured to not buffer log files.

setDsyncDatabases

public void setDsyncDatabases(boolean dsyncDatabases)

Configure the database environment to flush database writes to the backing disk before returning from the write system call, rather than flushing database writes explicitly in a separate system call, as necessary.

This is only available on some systems (for example, systems supporting the m4_posix1_name standard O_DSYNC flag, or systems supporting the Win32 FILE_FLAG_WRITE_THROUGH flag). This flag may result in inaccurate file modification times and other file-level information for Berkeley DB database files. This flag will almost certainly result in a performance decrease on most systems. This flag is only applicable to certain filesysystem (for example, the Veritas VxFS filesystem), where the filesystem's support for trickling writes back to stable storage behaves badly (or more likely, has been misconfigured).

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

dsyncDatabases - If true, configure the database environment to flush database writes to the backing disk before returning from the write system call, rather than flushing log writes explicitly in a separate system call.

getDsyncDatabases

public boolean getDsyncDatabases()

Return true if the database environment has been configured to flush database writes to the backing disk before returning from the write system call.

This method may be called at any time during the life of the application.

Returns:

True if the database environment has been configured to flush database writes to the backing disk before returning from the write system call.

setDsyncLog

public void setDsyncLog(boolean dsyncLog)

Configure the database environment to flush log writes to the backing disk before returning from the write system call, rather than flushing log writes explicitly in a separate system call.

This configuration is only available on some systems (for example, systems supporting the POSIX standard O_DSYNC flag, or systems supporting the Win32 FILE_FLAG_WRITE_THROUGH flag). This configuration may result in inaccurate file modification times and other file-level information for Berkeley DB log files. This configuration may offer a performance increase on some systems and a performance decrease on others.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

dsyncLog - If true, configure the database environment to flush log writes to the backing disk before returning from the write system call, rather than flushing log writes explicitly in a separate system call.

getDsyncLog

public boolean getDsyncLog()

Return true if the database environment has been configured to flush log writes to the backing disk before returning from the write system call.

This method may be called at any time during the life of the application.

Returns:

True if the database environment has been configured to flush log writes to the backing disk before returning from the write system call.

setEncrypted

public void setEncrypted(String password)

Set the password used to perform encryption and decryption.

Berkeley DB uses the Rijndael/AES (also known as the Advanced Encryption Standard and Federal Information Processing Standard (FIPS) 197) algorithm for encryption or decryption.

getEncrypted

public boolean getEncrypted()

Return the database environment has been configured to perform encryption.

This method may be called at any time during the life of the application.

Returns:

The database environment has been configured to perform encryption.

setErrorHandler

public void setErrorHandler(ErrorHandler errorHandler)

Set the function to be called if an error occurs.

When an error occurs in the Berkeley DB library, an exception is thrown. In some cases, however, the error information returned to the application may be insufficient to completely describe the cause of the error, especially during initial application debugging.

The EnvironmentConfig.setErrorHandler and DatabaseConfig.setErrorHandler methods are used to enhance the mechanism for reporting error messages to the application. In some cases, when an error occurs, Berkeley DB will invoke the ErrorHandler's object error method. It is up to this method to display the error message in an appropriate manner.

Alternatively, applications can use EnvironmentConfig.setErrorStream and DatabaseConfig.setErrorStream to display the additional information via an output stream. Applications should not mix these approaches.

This error-logging enhancement does not slow performance or significantly increase application size, and may be run during normal operation as well as during application debugging.

This method may be called at any time during the life of the application.

Parameters:

errorHandler - The function to be called if an error occurs.

getErrorHandler

public ErrorHandler getErrorHandler()

Return the function to be called if an error occurs.

This method may be called at any time during the life of the application.

Returns:

The function to be called if an error occurs.

setErrorPrefix

public void setErrorPrefix(String errorPrefix)

Set the prefix string that appears before error messages.

This method may be called at any time during the life of the application.

Parameters:

errorPrefix - The prefix string that appears before error messages.

getErrorPrefix

public String getErrorPrefix()

Return the prefix string that appears before error messages.

This method may be called at any time during the life of the application.

Returns:

The prefix string that appears before error messages.

setErrorStream

public void setErrorStream(OutputStream errorStream)

Set an OutputStream for displaying error messages.

When an error occurs in the Berkeley DB library, an exception is thrown. In some cases, however, the error information returned to the application may be insufficient to completely describe the cause of the error, especially during initial application debugging.

The EnvironmentConfig.setErrorStream and EnvironmentConfig.setErrorStream methods are used to enhance the mechanism for reporting error messages to the application by setting a OutputStream to be used for displaying additional Berkeley DB error messages. In some cases, when an error occurs, Berkeley DB will output an additional error message to the specified stream.

The error message will consist of the prefix string and a colon (":") (if a prefix string was previously specified using EnvironmentConfig.setErrorPrefix or DatabaseConfig.setErrorPrefix), an error string, and a trailing newline character.

Setting errorStream to null unconfigures the interface.

Alternatively, applications can use EnvironmentConfig.setErrorHandler and DatabaseConfig.setErrorHandler to capture the additional error information in a way that does not use output streams. Applications should not mix these approaches.

This error-logging enhancement does not slow performance or significantly increase application size, and may be run during normal operation as well as during application debugging.

This method may be called at any time during the life of the application.

Parameters:

errorStream - The application-specified OutputStream for error messages.

getErrorStream

public OutputStream getErrorStream()

Return the an OutputStream for displaying error messages.

This method may be called at any time during the life of the application.

Returns:

The an OutputStream for displaying error messages.

setFeedbackHandler

public void setFeedbackHandler(FeedbackHandler feedbackHandler)

Set an object whose methods are called to provide feedback.

Some operations performed by the Berkeley DB library can take non-trivial amounts of time. This method can be used by applications to monitor progress within these operations. When an operation is likely to take a long time, Berkeley DB will call the object's methods with progress information.

It is up to the object's methods to display this information in an appropriate manner.

This method configures only operations performed using a single a Environment handle

This method may be called at any time during the life of the application.

Parameters:

feedbackHandler - An object whose methods are called to provide feedback.

getFeedbackHandler

public FeedbackHandler getFeedbackHandler()

Return the object's methods to be called to provide feedback.

This method may be called at any time during the life of the application.

Returns:

The object's methods to be called to provide feedback.

setInitializeCache

public void setInitializeCache(boolean initializeCache)

Configure a shared memory buffer pool in the database environment.

This subsystem should be used whenever an application is using any Berkeley DB access method.

Parameters:

initializeCache - If true, configure a shared memory buffer pool in the database environment.

getInitializeCache

public boolean getInitializeCache()

Return true if the database environment is configured with a shared memory buffer pool.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured with a shared memory buffer pool.

setInitializeCDB

public void setInitializeCDB(boolean initializeCDB)

Configure the database environment for the Concurrent Data Store product.

In this mode, Berkeley DB provides multiple reader/single writer access. The only other subsystem that should be specified for this handle is a cache.

Parameters:

initializeCDB - If true, configure the database environment for the Concurrent Data Store product.

getInitializeCDB

public boolean getInitializeCDB()

Return true if the database environment is configured for the Concurrent Data Store product.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured for the Concurrent Data Store product.

setInitializeLocking

public void setInitializeLocking(boolean initializeLocking)

Configure the database environment for locking.

Locking should be used when multiple processes or threads are going to be reading and writing a database, so they do not interfere with each other. If all threads are accessing the database(s) read-only, locking is unnecessary. When locking is configured, it is usually necessary to run a deadlock detector, as well.

Parameters:

initializeLocking - If true, configure the database environment for locking.

getInitializeLocking

public boolean getInitializeLocking()

Return true if the database environment is configured for locking.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured for locking.

setInitializeLogging

public void setInitializeLogging(boolean initializeLogging)

Configure the database environment for logging.

Logging should be used when recovery from application or system failure is necessary. If the log region is being created and log files are already present, the log files are reviewed; subsequent log writes are appended to the end of the log, rather than overwriting current log entries.

Parameters:

initializeLogging - If true, configure the database environment for logging.

getInitializeLogging

public boolean getInitializeLogging()

Return true if the database environment is configured for logging.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured for logging.

setInitializeRegions

public void setInitializeRegions(boolean initializeRegions)

Configure the database environment to page-fault shared regions into memory when initially creating or joining a database environment.

In some applications, the expense of page-faulting the underlying shared memory regions can affect performance. For example, if the page-fault occurs while holding a lock, other lock requests can convoy, and overall throughput may decrease. This method configures Berkeley DB to page-fault shared regions into memory when initially creating or joining a database environment. In addition, Berkeley DB will write the shared regions when creating an environment, forcing the underlying virtual memory and filesystems to instantiate both the necessary memory and the necessary disk space. This can also avoid out-of-disk space failures later on.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

initializeRegions - If true, configure the database environment to page-fault shared regions into memory when initially creating or joining a database environment.

getInitializeRegions

public boolean getInitializeRegions()

Return true if the database environment has been configured to page-fault shared regions into memory when initially creating or joining a database environment.

This method may be called at any time during the life of the application.

Returns:

True if the database environment has been configured to page-fault shared regions into memory when initially creating or joining a database environment.

setInitializeReplication

public void setInitializeReplication(boolean initializeReplication)

Configure the database environment for replication.

Replication requires both locking and transactions.

Parameters:

initializeReplication - If true, configure the database environment for replication.

getInitializeReplication

public boolean getInitializeReplication()

Return true if the database environment is configured for replication.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured for replication.

setJoinEnvironment

public void setJoinEnvironment(boolean joinEnvironment)

Configure the handle to join an existing environment.

This option allows applications to join an existing environment without knowing which subsystems the environment supports.

Parameters:

joinEnvironment - If true, configure the handle to join an existing environment.

getJoinEnvironment

public boolean getJoinEnvironment()

Return the handle is configured to join an existing environment.

This method may be called at any time during the life of the application.

Returns:

The handle is configured to join an existing environment.

setLockConflicts

public void setLockConflicts(byte[][] lockConflicts)

Configure the locking conflicts matrix.

If the locking conflicts matrix is never configured, a standard conflicts array is used.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

lockConflicts - The locking conflicts matrix. A non-0 value for an array element indicates the requested_mode and held_mode conflict:

        lockConflicts[requested_mode][held_mode]
    

The not-granted mode must be represented by 0.

getLockConflicts

public byte[][] getLockConflicts()

Return the locking conflicts matrix.

This method may be called at any time during the life of the application.

Returns:

The locking conflicts matrix.

setLockDetectMode

public void setLockDetectMode(LockDetectMode lockDetectMode)

Configure if the deadlock detector is to be run whenever a lock conflict occurs.

The database environment's deadlock detector configuration may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lk_detect", one or more whitespace characters, and the method detect parameter as a string; for example, "set_lk_detect DB_LOCK_OLDEST". Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

Although the method may be called at any time during the life of the application, it should normally be called before opening the database environment.

Parameters:

lockDetectMode - The lock request(s) to be rejected. As transactions acquire locks on behalf of a single locker ID, rejecting a lock request associated with a transaction normally requires the transaction be aborted.

getLockDetectMode

public LockDetectMode getLockDetectMode()

Return true if the deadlock detector is configured to run whenever a lock conflict occurs.

This method may be called at any time during the life of the application.

Returns:

True if the deadlock detector is configured to run whenever a lock conflict occurs.

setLockDown

public void setLockDown(boolean lockDown)

Configure the database environment to lock shared environment files and memory-mapped databases into memory.

Parameters:

lockDown - If true, configure the database environment to lock shared environment files and memory-mapped databases into memory.

getLockDown

public boolean getLockDown()

Return true if the database environment is configured to lock shared environment files and memory-mapped databases into memory.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured to lock shared environment files and memory-mapped databases into memory.

setLockTimeout

public void setLockTimeout(long lockTimeout)

Set the timeout value for the database environment locks.

Lock timeouts are checked whenever a thread of control blocks on a lock or when deadlock detection is performed. The lock may have been requested explicitly through the Lock subsystem interfaces, or it may be a lock requested by the database access methods underlying the application. As timeouts are only checked when the lock request first blocks or when deadlock detection is performed, the accuracy of the timeout depends on how often deadlock detection is performed.

Timeout values specified for the database environment may be overridden on a per-lock basis by Environment.lockVector.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may be called at any time during the life of the application.

Parameters:

lockTimeout - The timeout value, specified as an unsigned 32-bit number of microseconds, limiting the maximum timeout to roughly 71 minutes.

Throws:

IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getLockTimeout

public long getLockTimeout()

Return the database environment lock timeout value, in microseconds; a timeout of 0 means no timeout is set.

This method may be called at any time during the life of the application.

Returns:

The database environment lock timeout value, in microseconds; a timeout of 0 means no timeout is set.

setLogAutoRemove

public void setLogAutoRemove(boolean logAutoRemove)

Configure the system to automatically remove log files that are no longer needed.

Automatic log file removal is likely to make catastrophic recovery impossible.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may be called at any time during the life of the application.

Parameters:

logAutoRemove - If true, configure the system to automatically remove log files that are no longer needed.

getLogAutoRemove

public boolean getLogAutoRemove()

Return true if the system has been configured to to automatically remove log files that are no longer needed.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to to automatically remove log files that are no longer needed.

setLogInMemory

public void setLogInMemory(boolean inmemory)

If set, maintain transaction logs in memory rather than on disk. This means that transactions exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be maintained, but if the application or system fails, integrity will not persist. All database files must be verified and/or restored from a replication group master or archival backup after application or system failure.

When in-memory logs are configured and no more log buffer space is available, Berkeley DB methods will throw a DatabaseException. When choosing log buffer and file sizes for in-memory logs, applications should ensure the in-memory log buffer size is large enough that no transaction will ever span the entire buffer, and avoid a state where the in-memory buffer is full and no space can be freed because a transaction that started in the first log "file" is still active.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

inmemory - If true, maintain transaction logs in memory rather than on disk.

getLogInMemory

public boolean getLogInMemory()

Return true if the database environment is configured to maintain transaction logs in memory rather than on disk.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured to maintain transaction logs in memory rather than on disk.

setLogRecordHandler

public void setLogRecordHandler(LogRecordHandler logRecordHandler)

Set a function to process application-specific log records.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may not be called after the environment has been opened. If joining an existing database environment, the information specified to this method must be consistent with the existing environment or corruption can occur.

Parameters:

logRecordHandler - The handler for application-specific log records.

getLogRecordHandler

public LogRecordHandler getLogRecordHandler()

Return the handler for application-specific log records.

This method may be called at any time during the life of the application.

Returns:

The handler for application-specific log records.

setMaxLocks

public void setMaxLocks(int maxLocks)

Set the maximum number of locks supported by the database environment.

This value is used during environment creation to estimate how much space to allocate for various lock-table data structures. The default value is 1000 locks.

The database environment's maximum number of locks may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lk_max_locks", one or more whitespace characters, and the number of locks. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

maxLocks - The maximum number of locks supported by the database environment.

getMaxLocks

public int getMaxLocks()

Return the maximum number of locks.

This method may be called at any time during the life of the application.

Returns:

The maximum number of locks.

setMaxLockers

public void setMaxLockers(int maxLockers)

Set the maximum number of locking entities supported by the database environment.

This value is used during environment creation to estimate how much space to allocate for various lock-table data structures. The default value is 1000 lockers.

The database environment's maximum number of lockers may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lk_max_lockers", one or more whitespace characters, and the number of lockers. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

maxLockers - The maximum number simultaneous locking entities supported by the database environment.

getMaxLockers

public int getMaxLockers()

Return the maximum number of lockers.

This method may be called at any time during the life of the application.

Returns:

The maximum number of lockers.

setMaxLockObjects

public void setMaxLockObjects(int maxLockObjects)

Set the maximum number of locked objects supported by the database environment.

This value is used during environment creation to estimate how much space to allocate for various lock-table data structures. The default value is 1000 objects.

The database environment's maximum number of objects may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lk_max_objects", one or more whitespace characters, and the number of objects. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

maxLockObjects - The maximum number of locked objects supported by the database environment.

getMaxLockObjects

public int getMaxLockObjects()

Return the maximum number of locked objects.

This method may be called at any time during the life of the application.

Returns:

The maximum number of locked objects.

setMaxLogFileSize

public void setMaxLogFileSize(int maxLogFileSize)

Set the maximum size of a single file in the log, in bytes.

By default, or if the maxLogFileSize parameter is set to 0, a size of 10MB is used. If no size is specified by the application, the size last specified for the database region will be used, or if no database region previously existed, the default will be used. Because LogSequenceNumber file offsets are unsigned four-byte values, the set value may not be larger than the maximum unsigned four-byte value.

The database environment's log file size may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lg_max", one or more whitespace characters, and the size in bytes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may be called at any time during the life of the application.

Parameters:

maxLogFileSize - The maximum size of a single file in the log, in bytes.

getMaxLogFileSize

public int getMaxLogFileSize()

Return the maximum size of a single file in the log, in bytes.

This method may be called at any time during the life of the application.

Returns:

The maximum size of a single file in the log, in bytes.

setLogBufferSize

public void setLogBufferSize(int logBufferSize)

Set the size of the in-memory log buffer, in bytes.

Log information is stored in-memory until the storage space fills up or transaction commit forces the information to be flushed to stable storage. In the presence of long-running transactions or transactions producing large amounts of data, larger buffer sizes can increase throughput.

By default, or if the value is set to 0, a size of 32K is used.

The database environment's log buffer size may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lg_bsize", one or more whitespace characters, and the size in bytes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

logBufferSize - The size of the in-memory log buffer, in bytes.

getLogBufferSize

public int getLogBufferSize()

Return the size of the in-memory log buffer, in bytes.

This method may be called at any time during the life of the application.

Returns:

The size of the in-memory log buffer, in bytes.

setLogDirectory

public void setLogDirectory(File logDirectory)

Set the path of a directory to be used as the location of logging files.

Log files created by the Log Manager subsystem will be created in this directory. If no logging directory is specified, log files are created in the environment home directory.

For the greatest degree of recoverability from system or application failure, database files and log files should be located on separate physical devices.

The database environment's logging directory may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lg_dir", one or more whitespace characters, and the directory name. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may not be called after the environment has been opened. If joining an existing database environment, the information specified to this method must be consistent with the existing environment or corruption can occur.

Parameters:

logDirectory - The directory used to store the logging files. On Windows platforms, this argument will be interpreted as a UTF-8 string, which is equivalent to ASCII for Latin characters.

getLogDirectory

public File getLogDirectory()

Return the path of a directory to be used as the location of logging files.

This method may be called at any time during the life of the application.

Returns:

The path of a directory to be used as the location of logging files.

getLogFileMode

public int getLogFileMode()

Return the absolute file mode for created log files.

This method may be called at any time during the life of the application.

Returns:

The absolute file mode for created log files.

setLogFileMode

public void setLogFileMode(int mode)

Set the absolute file mode for created log files. This method is only useful for the rare Berkeley DB application that does not control its umask value.

Normally, if Berkeley DB applications set their umask appropriately, all processes in the application suite will have read permission on the log files created by any process in the application suite. However, if the Berkeley DB application is a library, a process using the library might set its umask to a value preventing other processes in the application suite from reading the log files it creates. In this rare case, this method can be used to set the mode of created log files to an absolute value.

Parameters:

mode - The absolute mode of the created log file.

setLogRegionSize

public void setLogRegionSize(int logRegionSize)

Set the size of the underlying logging area of the database environment, in bytes.

By default, or if the value is set to 0, the default size is 60KB. The log region is used to store filenames, and so may need to be increased in size if a large number of files will be opened and registered with the specified database environment's log manager.

The database environment's log region size may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lg_regionmax", one or more whitespace characters, and the size in bytes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

logRegionSize - The size of the logging area in the database environment, in bytes.

getLogRegionSize

public int getLogRegionSize()

Return the size of the underlying logging subsystem region.

This method may be called at any time during the life of the application.

Returns:

The size of the underlying logging subsystem region.

setMaxOpenFiles

public void setMaxOpenFiles(int maxOpenFiles)

Limit the number of file descriptors the library will open concurrently when flushing dirty pages from the cache.

Parameters:

maxOpenFiles - The maximum number of file descriptors that may be concurrently opened by the library when flushing dirty pages from the cache.

getMaxOpenFiles

public int getMaxOpenFiles()

Return the maximum number of file descriptors that will be opened concurrently..

This method may be called at any time during the life of the application.

Returns:

The maximum number of file descriptors that will be opened concurrently..

setMaxWrite

public void setMaxWrite(int maxWrite,
                        int maxWriteSleep)

Limit the number of sequential write operations scheduled by the library when flushing dirty pages from the cache.

Parameters:

maxWrite - The maximum number of sequential write operations scheduled by the library when flushing dirty pages from the cache.

maxWriteSleep - The number of microseconds the thread of control should pause before scheduling further write operations.

getMaxWrite

public int getMaxWrite()

Return the maximum number of sequential write operations.

This method may be called at any time during the life of the application.

Returns:

The maximum number of sequential write operations.

getMaxWriteSleep

public int getMaxWriteSleep()

Return the microseconds to pause before scheduling further write operations.

This method may be called at any time during the life of the application.

Returns:

The microseconds to pause before scheduling further write operations.

setMessageHandler

public void setMessageHandler(MessageHandler messageHandler)

Set a function to be called with an informational message.

There are interfaces in the Berkeley DB library which either directly output informational messages or statistical information, or configure the library to output such messages when performing other operations, EnvironmentConfig.setVerboseDeadlock for example.

The EnvironmentConfig.setMessageHandler and DatabaseConfig.setMessageHandler methods are used to display these messages for the application.

Setting messageHandler to null unconfigures the interface.

Alternatively, you can use EnvironmentConfig.setMessageStream and DatabaseConfig.setMessageStream to send the additional information directly to an output streams. You should not mix these approaches.

This method may be called at any time during the life of the application.

Parameters:

messageHandler - The application-specified function for informational messages.

getMessageHandler

public MessageHandler getMessageHandler()

Return the function to be called with an informational message.

This method may be called at any time during the life of the application.

Returns:

The function to be called with an informational message.

setMessageStream

public void setMessageStream(OutputStream messageStream)

Set an OutputStream for displaying informational messages.

There are interfaces in the Berkeley DB library which either directly output informational messages or statistical information, or configure the library to output such messages when performing other operations, EnvironmentConfig.setVerboseDeadlock for example.

The EnvironmentConfig.setMessageStream and DatabaseConfig.setMessageStream methods are used to display these messages for the application. In this case, the message will include a trailing newline character.

Setting messageStream to null unconfigures the interface.

Alternatively, you can use EnvironmentConfig.setMessageHandler and DatabaseConfig.setMessageHandler to capture the additional information in a way that does not use output streams. You should not mix these approaches.

This method may be called at any time during the life of the application.

Parameters:

messageStream - The application-specified OutputStream for informational messages.

getMessageStream

public OutputStream getMessageStream()

Return the an OutputStream for displaying informational messages.

This method may be called at any time during the life of the application.

Returns:

The an OutputStream for displaying informational messages.

setMMapSize

public void setMMapSize(long mmapSize)

Set the maximum file size, in bytes, for a file to be mapped into the process address space.

If no value is specified, it defaults to 10MB.

Files that are opened read-only in the pool (and that satisfy a few other criteria) are, by default, mapped into the process address space instead of being copied into the local cache. This can result in better-than-usual performance because available virtual memory is normally much larger than the local cache, and page faults are faster than page copying on many systems. However, it can cause resource starvation in the presence of limited virtual memory, and it can result in immense process sizes in the presence of large databases.

Parameters:

mmapSize - The maximum file size, in bytes, for a file to be mapped into the process address space.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may be called at any time during the life of the application.

getMMapSize

public long getMMapSize()

Return the maximum file size, in bytes, for a file to be mapped into the process address space.

Returns:

The maximum file size, in bytes, for a file to be mapped into the process address space.

setMode

public void setMode(int mode)

Configure the database environment to use a specific mode when creating underlying files and shared memory segments.

On UNIX systems or in POSIX environments, files created in the database environment are created with the specified mode (as modified by the process' umask value at the time of creation).

On UNIX systems or in POSIX environments, system shared memory segments created by the library are created with the specified mode, unmodified by the process' umask value.

If is 0, the library will use a default mode of readable and writable by both owner and group.

Created files are owned by the process owner; the group ownership of created files is based on the system and directory defaults, and is not further specified by the library.

Parameters:

mode - The mode to use when creating underlying files and shared memory segments.

getMode

public long getMode()

Return the mode to use when creating underlying files and shared memory segments.

This method may be called at any time during the life of the application.

Returns:

The mode to use when creating underlying files and shared memory segments.

setMaxMutexes

public void setMaxMutexes(int maxMutexes)

Set the total number of mutexes to allocate.

Berkeley DB allocates a default number of mutexes based on the initial configuration of the database environment. That default calculation may be too small if the application has an unusual need for mutexes (for example, if the application opens an unexpectedly large number of databases) or too large (if the application is trying to minimize its memory footprint). This method is used to specify an absolute number of mutexes to allocate.

Calling this method discards any value previously set using the setMutexIncrement(int) method.

The database environment's total number of mutexes may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "mutex_set_max", one or more whitespace characters, and the total number of mutexes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

maxMutexes - The absolute number of mutexes to allocate.

getMaxMutexes

public int getMaxMutexes()

Return the total number of mutexes allocated.

This method may be called at any time during the life of the application.

Returns:

The total number of mutexes allocated.

setMutexAlignment

public void setMutexAlignment(int mutexAlignment)

Set the mutex alignment, in bytes.

It is sometimes advantageous to align mutexes on specific byte boundaries in order to minimize cache line collisions. This method specifies an alignment for mutexes allocated by Berkeley DB.

The database environment's mutex alignment may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "mutex_set_align", one or more whitespace characters, and the mutex alignment in bytes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

mutexAlignment - mutex alignment, in bytes. The mutex alignment must be a power-of-two.

getMutexAlignment

public int getMutexAlignment()

Return the mutex alignment, in bytes.

This method may be called at any time during the life of the application.

Returns:

The mutex alignment, in bytes.

setMutexIncrement

public void setMutexIncrement(int mutexIncrement)

Increase the number of mutexes to allocate.

Berkeley DB allocates a default number of mutexes based on the initial configuration of the database environment. That default calculation may be too small if the application has an unusual need for mutexes (for example, if the application opens an unexpectedly large number of databases) or too large (if the application is trying to minimize its memory footprint). This method configure the number of additional mutexes to allocate.

Calling this method discards any value previously set using the setMaxMutexes(int) method.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

mutexIncrement - The number of additional mutexes to allocate.

getMutexIncrement

public int getMutexIncrement()

Return the number of additional mutexes to allocate.

This method may be called at any time during the life of the application.

Returns:

The number of additional mutexes to allocate.

setMutexTestAndSetSpins

public void setMutexTestAndSetSpins(int mutexTestAndSetSpins)

Specify the number of times that test-and-set mutexes should spin without blocking. The value defaults to 1 on uniprocessor systems and to 50 times the number of processors on multiprocessor systems.

The database environment's test-and-set spin count may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_tas_spins", one or more whitespace characters, and the number of spins. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may be called at any time during the life of the application.

Parameters:

mutexTestAndSetSpins - The number of spins test-and-set mutexes should execute before blocking.

getMutexTestAndSetSpins

public int getMutexTestAndSetSpins()

Return the test-and-set spin count.

This method may be called at any time during the life of the application.

Returns:

The test-and-set spin count.

setNoLocking

public void setNoLocking(boolean noLocking)

Configure the system to grant all requested mutual exclusion mutexes and database locks without regard for their actual availability.

This functionality should never be used for purposes other than debugging.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle).

This method may be called at any time during the life of the application.

Parameters:

noLocking - If true, configure the system to grant all requested mutual exclusion mutexes and database locks without regard for their actual availability.

getNoLocking

public boolean getNoLocking()

Return true if the system has been configured to grant all requested mutual exclusion mutexes and database locks without regard for their actual availability.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to grant all requested mutual exclusion mutexes and database locks without regard for their actual availability.

setNoMMap

public void setNoMMap(boolean noMMap)

Configure the system to copy read-only database files into the local cache instead of potentially mapping them into process memory.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

noMMap - If true, configure the system to copy read-only database files into the local cache instead of potentially mapping them into process memory.

getNoMMap

public boolean getNoMMap()

Return true if the system has been configured to copy read-only database files into the local cache instead of potentially mapping them into process memory.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to copy read-only database files into the local cache instead of potentially mapping them into process memory.

setNoPanic

public void setNoPanic(boolean noPanic)

Configure the system to ignore any panic state in the database environment.

Database environments in a panic state normally refuse all attempts to call Berkeley DB functions, throwing RunRecoveryException. This functionality should never be used for purposes other than debugging.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle).

This method may be called at any time during the life of the application.

Parameters:

noPanic - If true, configure the system to ignore any panic state in the database environment.

getNoPanic

public boolean getNoPanic()

Return true if the system has been configured to ignore any panic state in the database environment.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to ignore any panic state in the database environment.

setOverwrite

public void setOverwrite(boolean overwrite)

Configure the system to overwrite files stored in encrypted formats before deleting them.

Berkeley DB overwrites files using alternating 0xff, 0x00 and 0xff byte patterns. For file overwriting to be effective, the underlying file must be stored on a fixed-block filesystem. Systems with journaling or logging filesystems will require operating system support and probably modification of the Berkeley DB sources.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle).

This method may be called at any time during the life of the application.

Parameters:

overwrite - If true, configure the system to overwrite files stored in encrypted formats before deleting them.

getOverwrite

public boolean getOverwrite()

Return true if the system has been configured to overwrite files stored in encrypted formats before deleting them.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to overwrite files stored in encrypted formats before deleting them.

setPanicHandler

public void setPanicHandler(PanicHandler panicHandler)

Set the function to be called if the database environment panics.

Errors can occur in the Berkeley DB library where the only solution is to shut down the application and run recovery (for example, if Berkeley DB is unable to allocate heap memory). In such cases, the Berkeley DB methods will throw a RunRecoveryException. It is often easier to simply exit the application when such errors occur rather than gracefully return up the stack. This method specifies a function to be called when RunRecoveryException is about to be thrown from a Berkeley DB method.

This method may be called at any time during the life of the application.

Parameters:

panicHandler - The function to be called if the database environment panics.

getPanicHandler

public PanicHandler getPanicHandler()

Return the function to be called if the database environment panics.

This method may be called at any time during the life of the application.

Returns:

The function to be called if the database environment panics.

setPrivate

public void setPrivate(boolean isPrivate)

Configure the database environment to only be accessed by a single process (although that process may be multithreaded).

This has two effects on the database environment. First, all underlying data structures are allocated from per-process memory instead of from shared memory that is potentially accessible to more than a single process. Second, mutexes are only configured to work between threads.

This flag should not be specified if more than a single process is accessing the environment because it is likely to cause database corruption and unpredictable behavior. For example, if both a server application and the a Berkeley DB utility are expected to access the environment, the database environment should not be configured as private.

Parameters:

isPrivate - If true, configure the database environment to only be accessed by a single process.

getPrivate

public boolean getPrivate()

Return true if the database environment is configured to only be accessed by a single process.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured to only be accessed by a single process.

setRegister

public void setRegister(boolean register)

Check if a process has failed while using the database environment, that is, if a process has exited with an open Environment handle. (For this check to be accurate, all processes using the environment must specify this flag when opening the environment.) If recovery needs to be run for any reason and either setRunRecovery(boolean) or setRunFatalRecovery(boolean) are also specified, recovery will be performed and the open will proceed normally. If recovery needs to be run and no recovery flag is specified, a RunRecoveryException will be thrown. If recovery does not need to be run, the recovery flags will be ignored. See Architecting Transactional Data Store applications) for more information.

Parameters:

register - If true, check for process failure when the environment is opened.

getRegister

public boolean getRegister()

Return true if the check for process failure when the environment is opened.

This method may be called at any time during the life of the application.

Returns:

True if the check for process failure when the environment is opened.

setReplicationLimit

public void setReplicationLimit(long replicationLimit)

Impose a byte-count limit on the amount of data that will be transmitted from a site in a single call to Environment.processReplicationMessage.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called before the database environment is opened.

Parameters:

replicationLimit - The maximum number of bytes that will be sent in a single call to Environment.processReplicationMessage.

getReplicationLimit

public long getReplicationLimit()

Return the transmit limit in bytes for a single call to Environment.processReplicationMessage.

This method may be called at any time during the life of the application.

Returns:

The transmit limit in bytes for a single call to Environment.processReplicationMessage.

setReplicationTransport

public void setReplicationTransport(int envid,
                                    ReplicationTransport replicationTransport)

Initialize the communication infrastructure for a database environment participating in a replicated application.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may be called at any time during the life of the application.

Parameters:

envid - The local environment's ID. It must be a positive integer and uniquely identify this Berkeley DB database environment.

replicationTransport - The callback function is used to transmit data using the replication application's communication infrastructure.

getReplicationTransport

public ReplicationTransport getReplicationTransport()

Return the replication callback function used to transmit data using the replication application's communication infrastructure.

Returns:

The replication callback function used to transmit data using the replication application's communication infrastructure.

setRunFatalRecovery

public void setRunFatalRecovery(boolean runFatalRecovery)

Configure to run catastrophic recovery on this environment before opening it for normal use.

A standard part of the recovery process is to remove the existing database environment and create a new one. Applications running recovery must be prepared to re-create the environment because underlying shared regions will be removed and re-created.

If the thread of control performing recovery does not specify the correct database environment initialization information (for example, the correct memory pool cache size), the result can be an application running in an environment with incorrect cache and other subsystem sizes. For this reason, the thread of control performing recovery should specify correct configuration information before recovering the environment; or it should remove the environment after recovery is completed, leaving creation of a correctly sized environment to a subsequent call.

All recovery processing must be single-threaded; that is, only a single thread of control may perform recovery or access a database environment while recovery is being performed. Because it is not an error to run recovery for an environment for which no recovery is required, it is reasonable programming practice for the thread of control responsible for performing recovery and creating the environment to always specify recovery during startup.

This method returns successfully if recovery is run no log files exist, so it is necessary to ensure that all necessary log files are present before running recovery.

Parameters:

runFatalRecovery - If true, configure to run catastrophic recovery on this environment before opening it for normal use.

getRunFatalRecovery

public boolean getRunFatalRecovery()

Return the handle is configured to run catastrophic recovery on the database environment before opening it for use.

This method may be called at any time during the life of the application.

Returns:

The handle is configured to run catastrophic recovery on the database environment before opening it for use.

setRunRecovery

public void setRunRecovery(boolean runRecovery)

Configure to run normal recovery on this environment before opening it for normal use.

A standard part of the recovery process is to remove the existing database environment and create a new one. Applications running recovery must be prepared to re-create the environment because underlying shared regions will be removed and re-created.

If the thread of control performing recovery does not specify the correct database environment initialization information (for example, the correct memory pool cache size), the result can be an application running in an environment with incorrect cache and other subsystem sizes. For this reason, the thread of control performing recovery should specify correct configuration information before recovering the environment; or it should remove the environment after recovery is completed, leaving creation of a correctly sized environment to a subsequent call.

All recovery processing must be single-threaded; that is, only a single thread of control may perform recovery or access a database environment while recovery is being performed. Because it is not an error to run recovery for an environment for which no recovery is required, it is reasonable programming practice for the thread of control responsible for performing recovery and creating the environment to always specify recovery during startup.

This method returns successfully if recovery is run no log files exist, so it is necessary to ensure that all necessary log files are present before running recovery.

Parameters:

runRecovery - If true, configure to run normal recovery on this environment before opening it for normal use.

getRunRecovery

public boolean getRunRecovery()

Return the handle is configured to run normal recovery on the database environment before opening it for use.

This method may be called at any time during the life of the application.

Returns:

The handle is configured to run normal recovery on the database environment before opening it for use.

setSystemMemory

public void setSystemMemory(boolean systemMemory)

Configure the database environment to allocate memory from system shared memory instead of from memory backed by the filesystem.

Parameters:

systemMemory - If true, configure the database environment to allocate memory from system shared memory instead of from memory backed by the filesystem.

getSystemMemory

public boolean getSystemMemory()

Return true if the database environment is configured to allocate memory from system shared memory instead of from memory backed by the filesystem.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured to allocate memory from system shared memory instead of from memory backed by the filesystem.

setRPCServer

public void setRPCServer(String rpcServer,
                         long rpcClientTimeout,
                         long rpcServerTimeout)

Establish a connection to a RPC server for this database environment.

After this method is called, subsequent calls to Berkeley DB library interfaces may throw exceptions encapsulating DB_NOSERVER, DB_NOSERVER_ID or DB_NOSERVER_HOME.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may not be called after the environment has been opened.

Parameters:

rpcServer - The host to which the client will connect and create a channel for communication.

rpcClientTimeout - The number of seconds the client should wait for results to come back from the server. Once the timeout has expired on any communication with the server, DatabaseException encapsulating DB_NOSERVER will be thrown. If this value is zero, a default timeout is used.

rpcServerTimeout - The number of seconds the server should allow a client connection to remain idle before assuming that the client is gone. Once that timeout has been reached, the server releases all resources associated with that client connection. Subsequent attempts by that client to communicate with the server result in an error return, indicating that an invalid identifier has been given to the server. This value can be considered a hint to the server. The server may alter this value based on its own policies or allowed values. If this value is zero, a default timeout is used.

setSegmentId

public void setSegmentId(long segmentId)

Specify a base segment ID for database environment shared memory regions created in system memory on VxWorks or systems supporting X/Open-style shared memory interfaces; for example, UNIX systems supporting shmget and related System V IPC interfaces.

This base segment ID will be used when database environment shared memory regions are first created. It will be incremented a small integer value each time a new shared memory region is created; that is, if the base ID is 35, the first shared memory region created will have a segment ID of 35, and the next one will have a segment ID between 36 and 40 or so. A database environment always creates a master shared memory region; an additional shared memory region for each of the subsystems supported by the environment (Locking, Logging, Memory Pool and Transaction); plus an additional shared memory region for each additional memory pool cache that is supported. Already existing regions with the same segment IDs will be removed.

The intent behind this method is two-fold: without it, applications have no way to ensure that two Berkeley DB applications don't attempt to use the same segment IDs when creating different database environments. In addition, by using the same segment IDs each time the environment is created, previously created segments will be removed, and the set of segments on the system will not grow without bound. The database environment's base segment ID may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_shm_key", one or more whitespace characters, and the ID. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may not be called after the environment has been opened. If joining an existing database environment, the information specified to this method must be consistent with the existing environment or corruption can occur.

Parameters:

segmentId - The base segment ID for the database environment.

getSegmentId

public long getSegmentId()

Return the base segment ID.

This method may be called at any time during the life of the application.

Returns:

The base segment ID.

setTemporaryDirectory

public void setTemporaryDirectory(File temporaryDirectory)

Set the path of a directory to be used as the location of temporary files.

The files created to back in-memory access method databases will be created relative to this path. These temporary files can be quite large, depending on the size of the database.

If no directory is specified, the following alternatives are checked in the specified order. The first existing directory path is used for all temporary files.

1. The value of the environment variable TMPDIR.
2. The value of the environment variable TEMP.
3. The value of the environment variable TMP.
4. The value of the environment variable TempFolder.
5. The value returned by the GetTempPath interface.
6. The directory /var/tmp.
7. The directory /usr/tmp.
8. The directory /temp.
9. The directory /tmp.
10. The directory C:/temp.
11. The directory C:/tmp.

    Note: the environment variables are only checked if the database environment has been configured with one of EnvironmentConfig.setUseEnvironment or EnvironmentConfig.setUseEnvironmentRoot.

    Note: the GetTempPath interface is only checked on Win/32 platforms.

    The database environment's temporary file directory may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_tmp_dir", one or more whitespace characters, and the directory name. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

    This method configures only operations performed using a single a Environment handle, not an entire database environment.

    This method may not be called after the environment has been opened. If joining an existing database environment, the information specified to this method must be consistent with the existing environment or corruption can occur.

    Parameters:

    temporaryDirectory - The directory to be used to store temporary files. On Windows platforms, this argument will be interpreted as a UTF-8 string, which is equivalent to ASCII for Latin characters.

getTemporaryDirectory

public File getTemporaryDirectory()

Return the path of a directory to be used as the location of temporary files.

This method may be called at any time during the life of the application.

Returns:

The path of a directory to be used as the location of temporary files.

setTestAndSetSpins

public void setTestAndSetSpins(int testAndSetSpins)

Set the number of times test-and-set mutexes should spin before blocking.

The value defaults to 1 on uniprocessor systems and to 50 times the number of processors on multiprocessor systems.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may be called at any time during the life of the application.

Parameters:

testAndSetSpins - The number of times test-and-set mutexes should spin before blocking.

getTestAndSetSpins

public int getTestAndSetSpins()

Return the number of times test-and-set mutexes should spin before blocking.

This method may be called at any time during the life of the application.

Returns:

The number of times test-and-set mutexes should spin before blocking.

setThreaded

public void setThreaded(boolean threaded)

Configure the handle to be free-threaded; that is, usable by multiple threads within a single address space.

This is the default; threading is always assumed in Java, so no special configuration is required.

Parameters:

threaded - If true, configure the handle to be free-threaded.

getThreaded

public boolean getThreaded()

Return true if the handle is configured to be free-threaded.

This method may be called at any time during the life of the application.

Returns:

True if the handle is configured to be free-threaded.

setTxnNoSync

public void setTxnNoSync(boolean txnNoSync)

Configure the system to not write or synchronously flush the log on transaction commit.

This means that transactions exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be maintained, but if the application or system fails, it is possible some number of the most recently committed transactions may be undone during recovery. The number of transactions at risk is governed by how many log updates can fit into the log buffer, how often the operating system flushes dirty buffers to disk, and how often the log is checkpointed.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

txnNoSync - If true, configure the system to not write or synchronously flush the log on transaction commit.

getTxnNoSync

public boolean getTxnNoSync()

Return true if the system has been configured to not write or synchronously flush the log on transaction commit.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to not write or synchronously flush the log on transaction commit.

setTxnNotDurable

public void setTxnNotDurable(boolean txnNotDurable)

Configure the system to not write log records.

This means that transactions exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be maintained, but if the application or system fails, integrity will not persist. All database files must be verified and/or restored from backup after a failure. In order to ensure integrity after application shut down, all database handles must be closed without specifying noSync, or all database changes must be flushed from the database environment cache using the Environment.checkpoint.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

txnNotDurable - If true, configure the system to not write log records.

getTxnNotDurable

public boolean getTxnNotDurable()

Return true if the system has been configured to not write log records.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to not write log records.

setTxnMaxActive

public void setTxnMaxActive(int txnMaxActive)

Configure the database environment to support at least txnMaxActive active transactions.

This value bounds the size of the memory allocated for transactions. Child transactions are counted as active until they either commit or abort.

When all of the memory available in the database environment for transactions is in use, calls to Environment.beginTransaction will fail (until some active transactions complete). If this interface is never called, the database environment is configured to support at least 20 active transactions.

The database environment's number of active transactions may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_tx_max", one or more whitespace characters, and the number of transactions. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may not be called after the environment has been opened. If joining an existing database environment, any information specified to this method will be ignored.

Parameters:

txnMaxActive - The minimum number of simultaneously active transactions supported by the database environment.

getTxnMaxActive

public int getTxnMaxActive()

Return the minimum number of simultaneously active transactions supported by the database environment.

Returns:

The minimum number of simultaneously active transactions supported by the database environment.

setTxnTimeout

public void setTxnTimeout(long txnTimeout)

Set the timeout value for the database environment transactions.

Transaction timeouts are checked whenever a thread of control blocks on a lock or when deadlock detection is performed. The lock is one requested on behalf of a transaction, normally by the database access methods underlying the application. As timeouts are only checked when the lock request first blocks or when deadlock detection is performed, the accuracy of the timeout depends on how often deadlock detection is performed.

Timeout values specified for the database environment may be overridden on a per-transaction basis by Transaction.setTxnTimeout.

This method configures a database environment, including all threads of control accessing the database environment, not only the operations performed using a specified Environment handle.

This method may be called at any time during the life of the application.

Parameters:

txnTimeout - The timeout value, specified as an unsigned 32-bit number of microseconds, limiting the maximum timeout to roughly 71 minutes.

Throws:

IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getTxnTimeout

public long getTxnTimeout()

Return the database environment transaction timeout value, in microseconds; a timeout of 0 means no timeout is set.

This method may be called at any time during the life of the application.

Returns:

The database environment transaction timeout value, in microseconds; a timeout of 0 means no timeout is set.

setTxnTimestamp

public void setTxnTimestamp(Date txnTimestamp)

Recover to the specified time rather than to the most current possible date.

Once a database environment has been upgraded to a new version of Berkeley DB involving a log format change, it is no longer possible to recover to a specific time before that upgrade.

This method configures only operations performed using a single a Environment handle, not an entire database environment.

This method may not be called after the environment has been opened.

Parameters:

txnTimestamp - The recovery timestamp. Only the seconds (not the milliseconds) of the timestamp are used.

getTxnTimestamp

public Date getTxnTimestamp()

Return the time to which recovery will be done, or 0 if recovery will be done to the most current possible date.

Returns:

The time to which recovery will be done, or 0 if recovery will be done to the most current possible date.

setTxnWriteNoSync

public void setTxnWriteNoSync(boolean txnWriteNoSync)

Configure the system to write, but not synchronously flush, the log on transaction commit.

This means that transactions exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be maintained, but if the system fails, it is possible some number of the most recently committed transactions may be undone during recovery. The number of transactions at risk is governed by how often the system flushes dirty buffers to disk and how often the log is checkpointed.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

txnWriteNoSync - If true, configure the system to write, but not synchronously flush, the log on transaction commit.

getTxnWriteNoSync

public boolean getTxnWriteNoSync()

Return true if the system has been configured to write, but not synchronously flush, the log on transaction commit.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to write, but not synchronously flush, the log on transaction commit.

setUseEnvironment

public void setUseEnvironment(boolean useEnvironment)

Configure the database environment to accept information from the process environment when naming files, regardless of the status of the process.

Because permitting users to specify which files are used can create security problems, environment information will be used in file naming for all users only if configured to do so.

Parameters:

useEnvironment - If true, configure the database environment to accept information from the process environment when naming files.

getUseEnvironment

public boolean getUseEnvironment()

Return true if the database environment is configured to accept information from the process environment when naming files.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured to accept information from the process environment when naming files.

setUseEnvironmentRoot

public void setUseEnvironmentRoot(boolean useEnvironmentRoot)

Configure the database environment to accept information from the process environment when naming files, if the process has appropriate permissions (for example, users with a user-ID of 0 on UNIX systems).

Because permitting users to specify which files are used can create security problems, environment information will be used in file naming for all users only if configured to do so.

Parameters:

useEnvironmentRoot - If true, configure the database environment to accept information from the process environment when naming files if the process has appropriate permissions.

getUseEnvironmentRoot

public boolean getUseEnvironmentRoot()

Return true if the database environment is configured to accept information from the process environment when naming files if the process has appropriate permissions.

This method may be called at any time during the life of the application.

Returns:

True if the database environment is configured to accept information from the process environment when naming files if the process has appropriate permissions.

setVerboseDeadlock

public void setVerboseDeadlock(boolean verboseDeadlock)

Display additional information when doing deadlock detection.

This method may be called at any time during the life of the application.

Parameters:

verboseDeadlock - If true, display additional information when doing deadlock detection.

getVerboseDeadlock

public boolean getVerboseDeadlock()

Return if the database environment is configured to display additional information when doing deadlock detection.

This method may be called at any time during the life of the application.

Returns:

If the database environment is configured to display additional information when doing deadlock detection.

setVerboseRecovery

public void setVerboseRecovery(boolean verboseRecovery)

Display additional information when performing recovery.

This method may be called at any time during the life of the application.

Parameters:

verboseRecovery - If true, display additional information when performing recovery.

getVerboseRecovery

public boolean getVerboseRecovery()

Return if the database environment is configured to display additional information when performing recovery.

This method may be called at any time during the life of the application.

Returns:

If the database environment is configured to display additional information when performing recovery.

setVerboseRegister

public void setVerboseRegister(boolean verboseRegister)

Display additional information concerning support for the setRegister(boolean) method.

This method may be called at any time during the life of the application.

Parameters:

verboseRegister - If true, display additional information concerning support for the setRegister(boolean) method

getVerboseRegister

public boolean getVerboseRegister()

Return if the database environment is configured to display additional information concerning support for the setRegister(boolean) method.

This method may be called at any time during the life of the application.

Returns:

If the database environment is configured to display additional information concerning support for the setRegister(boolean) method.

setVerboseReplication

public void setVerboseReplication(boolean verboseReplication)

Display additional information when processing replication messages.

Note, to get complete replication logging when debugging replication applications, you must also configure and build the Berkeley DB library with the --enable-diagnostic configuration option as well as call this method.

This method may be called at any time during the life of the application.

Parameters:

verboseReplication - If true, display additional information when processing replication messages.

getVerboseReplication

public boolean getVerboseReplication()

Return if the database environment is configured to display additional information when processing replication messages.

This method may be called at any time during the life of the application.

Returns:

If the database environment is configured to display additional information when processing replication messages.

setVerboseWaitsFor

public void setVerboseWaitsFor(boolean verboseWaitsFor)

Display the waits-for table when doing deadlock detection.

This method may be called at any time during the life of the application.

Parameters:

verboseWaitsFor - If true, display the waits-for table when doing deadlock detection.

getVerboseWaitsFor

public boolean getVerboseWaitsFor()

Return if the database environment is configured to display the waits-for table when doing deadlock detection.

This method may be called at any time during the life of the application.

Returns:

If the database environment is configured to display the waits-for table when doing deadlock detection.

setYieldCPU

public void setYieldCPU(boolean yieldCPU)

Configure the system to yield the processor immediately after each page or mutex acquisition.

This functionality should never be used for purposes other than stress testing.

This method only affects the specified Environment handle (and any other library handles opened within the scope of that handle). For consistent behavior across the environment, all Environment handles opened in the database environment must either call this method or the configuration should be specified in the database environment's DB_CONFIG configuration file.

This method may be called at any time during the life of the application.

Parameters:

yieldCPU - If true, configure the system to yield the processor immediately after each page or mutex acquisition.

getYieldCPU

public boolean getYieldCPU()

Return true if the system has been configured to yield the processor immediately after each page or mutex acquisition.

This method may be called at any time during the life of the application.

Returns:

True if the system has been configured to yield the processor immediately after each page or mutex acquisition.