com.sleepycat.je

Class EnvironmentMutableConfig

java.lang.Object

com.sleepycat.je.EnvironmentMutableConfig

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:

EnvironmentConfig

public class EnvironmentMutableConfig
extends java.lang.Object
implements java.lang.Cloneable, java.io.Serializable

Specifies the environment attributes that may be changed after the environment has been opened. EnvironmentMutableConfig is a parameter to Environment.setMutableConfig(com.sleepycat.je.EnvironmentMutableConfig) and is returned by Environment.getMutableConfig().

There are two types of mutable environment properties: per-environment handle properties, and environment wide properties.

Per-Environment Handle Properties

Per-environment handle properties apply only to a single Environment instance. For example, to change the default transaction commit behavior for a single environment handle, do this:

     // Specify no-sync behavior for a given handle.
     EnvironmentMutableConfig mutableConfig = env.getMutableConfig();
     mutableConfig.setDurability(Durability.COMMIT_NO_SYNC);
     env.setMutableConfig(mutableConfig);
 

The per-environment handle properties are listed below. These properties are accessed using the setter and getter methods listed, as shown in the example above.

• setDurability(com.sleepycat.je.Durability), getDurability()
• setTxnNoSync(boolean), getTxnNoSync() deprecated
• setTxnWriteNoSync(boolean), getTxnWriteNoSync() deprecated

Environment-Wide Mutable Properties

Environment-wide mutable properties are those that can be changed for an environment as a whole, irrespective of which environment instance (for the same physical environment) is used. For example, to stop the cleaner daemon thread, do this:

     // Stop the cleaner daemon threads for the environment.
     EnvironmentMutableConfig mutableConfig = env.getMutableConfig();
     mutableConfig.setConfigParam(EnvironmentConfig.ENV_RUN_CLEANER, "false");
     env.setMutableConfig(mutableConfig);
 

The environment-wide mutable properties are documented as such for each EnvironmentConfig String constant.

Getting the Current Environment Properties

To get the current "live" properties of an environment after constructing it or changing its properties, you must call Environment.getConfig() or Environment.getMutableConfig(). The original EnvironmentConfig or EnvironmentMutableConfig object used to set the properties is not kept up to date as properties are changed, and does not reflect property validation or properties that are computed.

See Also:

EnvironmentConfig, Serialized Form

Constructor Summary

Constructors

Constructor and Description
EnvironmentMutableConfig() An instance created using the default constructor is initialized with the system's default settings.

Method Summary

Modifier and Type	Method and Description
CacheMode	getCacheMode() Returns the default CacheMode used for operations performed in this environment, or null if CacheMode.DEFAULT is used.
int	getCachePercent() A convenience method for getting EnvironmentConfig.MAX_MEMORY_PERCENT.
long	getCacheSize() Returns the memory available to the database system, in bytes.
java.lang.String	getConfigParam(java.lang.String paramName) Returns the value for this configuration parameter.
Durability	getDurability() Convenience method for setting EnvironmentConfig.TXN_DURABILITY.
ExceptionListener	getExceptionListener() Returns the exception listener, if set.
long	getMaxDisk() A convenience method for getting EnvironmentConfig.MAX_DISK.
long	getOffHeapCacheSize() A convenience method for getting EnvironmentConfig.MAX_OFF_HEAP_MEMORY.
boolean	getTxnNoSync() Deprecated. replaced by getDurability()
boolean	getTxnWriteNoSync() Deprecated. replaced by getDurability()
EnvironmentMutableConfig	setCacheMode(CacheMode cacheMode) Sets the default CacheMode used for operations performed in this environment.
EnvironmentMutableConfig	setCachePercent(int percent) A convenience method for setting EnvironmentConfig.MAX_MEMORY_PERCENT.
EnvironmentMutableConfig	setCacheSize(long totalBytes) A convenience method for setting EnvironmentConfig.MAX_MEMORY.
EnvironmentMutableConfig	setConfigParam(java.lang.String paramName, java.lang.String value) Set this configuration parameter.
EnvironmentMutableConfig	setDurability(Durability durability) Convenience method for setting EnvironmentConfig.TXN_DURABILITY.
EnvironmentMutableConfig	setExceptionListener(ExceptionListener exceptionListener) Sets the exception listener for an Environment.
EnvironmentMutableConfig	setMaxDisk(long totalBytes) A convenience method for setting EnvironmentConfig.MAX_DISK.
EnvironmentMutableConfig	setOffHeapCacheSize(long totalBytes) A convenience method for setting EnvironmentConfig.MAX_OFF_HEAP_MEMORY.
EnvironmentMutableConfig	setTxnNoSync(boolean noSync) Deprecated. replaced by setDurability(com.sleepycat.je.Durability)
EnvironmentMutableConfig	setTxnWriteNoSync(boolean writeNoSync) Deprecated. replaced by setDurability(com.sleepycat.je.Durability)
java.lang.String	toString() Display configuration values.

Methods inherited from class java.lang.Object

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

Constructor Detail

EnvironmentMutableConfig

public EnvironmentMutableConfig()

An instance created using the default constructor is initialized with the system's default settings.

Method Detail

setTxnNoSync

public EnvironmentMutableConfig setTxnNoSync(boolean noSync)

Deprecated. replaced by setDurability(com.sleepycat.je.Durability)

Configures the database environment for asynchronous transactions.

Parameters:

noSync - If true, do 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 is maintained, but if the JVM or operating 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 updates fit into a log buffer, how often the operating system flushes dirty buffers to disk, and how often the database environment is checkpointed.

This attribute is false by default for this class and for the database environment.

getTxnNoSync

public boolean getTxnNoSync()

Deprecated. replaced by getDurability()

Returns true if the database environment is configured for asynchronous transactions.

Returns:

true if the database environment is configured for asynchronous transactions.

setTxnWriteNoSync

public EnvironmentMutableConfig setTxnWriteNoSync(boolean writeNoSync)

Deprecated. replaced by setDurability(com.sleepycat.je.Durability)

Configures the database environment for transactions which write but do not flush the log.

Parameters:

writeNoSync - If true, write but do 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 is maintained, but if the operating 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 operating system flushes dirty buffers to disk, and how often the database environment is checkpointed.

The motivation for this attribute is to provide a transaction that has more durability than asynchronous (nosync) transactions, but has higher performance than synchronous transactions.

This attribute is false by default for this class and for the database environment.

getTxnWriteNoSync

public boolean getTxnWriteNoSync()

Deprecated. replaced by getDurability()

Returns true if the database environment is configured for transactions which write but do not flush the log.

Returns:

true if the database environment is configured for transactions which write but do not flush the log.

setDurability

public EnvironmentMutableConfig setDurability(Durability durability)

Convenience method for setting EnvironmentConfig.TXN_DURABILITY.

Parameters:

durability - the new durability definition

Returns:

this

See Also:

Durability

getDurability

public Durability getDurability()

Convenience method for setting EnvironmentConfig.TXN_DURABILITY.

Returns:

the durability setting currently associated with this config.

setCacheSize

public EnvironmentMutableConfig setCacheSize(long totalBytes)
                                      throws java.lang.IllegalArgumentException

A convenience method for setting EnvironmentConfig.MAX_MEMORY.

Parameters:

totalBytes - The memory available to the database system, in bytes.

Returns:

this

Throws:

java.lang.IllegalArgumentException - if an invalid parameter is specified.

See Also:

EnvironmentConfig.MAX_MEMORY

getCacheSize

public long getCacheSize()

Returns the memory available to the database system, in bytes. A valid value is only available if this EnvironmentConfig object has been returned from Environment.getConfig().

Returns:

The memory available to the database system, in bytes.

setCachePercent

public EnvironmentMutableConfig setCachePercent(int percent)
                                         throws java.lang.IllegalArgumentException

A convenience method for setting EnvironmentConfig.MAX_MEMORY_PERCENT.

Parameters:

percent - The percent of JVM memory to allocate to the JE cache.

Returns:

this

Throws:

java.lang.IllegalArgumentException - if an invalid parameter is specified.

See Also:

EnvironmentConfig.MAX_MEMORY_PERCENT

getCachePercent

public int getCachePercent()

A convenience method for getting EnvironmentConfig.MAX_MEMORY_PERCENT.

Returns:

the percentage value used in the JE cache size calculation.

setOffHeapCacheSize

public EnvironmentMutableConfig setOffHeapCacheSize(long totalBytes)
                                             throws java.lang.IllegalArgumentException

A convenience method for setting EnvironmentConfig.MAX_OFF_HEAP_MEMORY.

Throws:

java.lang.IllegalArgumentException

getOffHeapCacheSize

public long getOffHeapCacheSize()

A convenience method for getting EnvironmentConfig.MAX_OFF_HEAP_MEMORY.

setMaxDisk

public EnvironmentMutableConfig setMaxDisk(long totalBytes)
                                    throws java.lang.IllegalArgumentException

A convenience method for setting EnvironmentConfig.MAX_DISK.

Parameters:

totalBytes - is an upper limit on the number of bytes used for data storage, or zero if no limit is desired.

Returns:

this

Throws:

java.lang.IllegalArgumentException - if an invalid parameter is specified.

See Also:

EnvironmentConfig.MAX_DISK

getMaxDisk

public long getMaxDisk()

A convenience method for getting EnvironmentConfig.MAX_DISK.

Returns:

the upper limit on the number of bytes used for data storage, or zero if no limit is set.

See Also:

EnvironmentConfig.MAX_DISK

setExceptionListener

public EnvironmentMutableConfig setExceptionListener(ExceptionListener exceptionListener)

Sets the exception listener for an Environment. The listener is called when a daemon thread throws an exception, in order to provide a notification mechanism for these otherwise asynchronous exceptions. Daemon thread exceptions are also printed through stderr.

Not all daemon exceptions are fatal, and the application bears responsibility for choosing how to respond to the notification. Since exceptions may repeat, the application should also choose how to handle a spate of exceptions. For example, the application may choose to act upon each notification, or it may choose to batch up its responses by implementing the listener so it stores exceptions, and only acts when a certain number have been received.

Parameters:

exceptionListener - the callback to be executed when an exception occurs.

Returns:

this

getExceptionListener

public ExceptionListener getExceptionListener()

Returns the exception listener, if set.

setCacheMode

public EnvironmentMutableConfig setCacheMode(CacheMode cacheMode)

Sets the default CacheMode used for operations performed in this environment. The default cache mode may be overridden on a per-database basis using DatabaseConfig.setCacheMode(com.sleepycat.je.CacheMode), and on a per-record or per-operation basis using Cursor.setCacheMode(com.sleepycat.je.CacheMode), ReadOptions.setCacheMode(CacheMode) or WriteOptions.setCacheMode(CacheMode).

Parameters:

cacheMode - is the default CacheMode used for operations performed in this environment. If null is specified, CacheMode.DEFAULT will be used.

Since:

4.0.97

See Also:

for further details.

getCacheMode

public CacheMode getCacheMode()

Returns the default CacheMode used for operations performed in this environment, or null if CacheMode.DEFAULT is used.

Returns:

the default CacheMode used for operations performed on this database, or null if CacheMode.DEFAULT is used.

Since:

4.0.97

See Also:

setCacheMode(com.sleepycat.je.CacheMode)

setConfigParam

public EnvironmentMutableConfig setConfigParam(java.lang.String paramName,
                                               java.lang.String value)
                                        throws java.lang.IllegalArgumentException

Set this configuration parameter. First validate the value specified for the configuration parameter; if it is valid, the value is set in the configuration.

Parameters:

paramName - the configuration parameter name, one of the String constants in this class

value - The configuration value

Returns:

this

Throws:

java.lang.IllegalArgumentException - if the paramName or value is invalid.

getConfigParam

public java.lang.String getConfigParam(java.lang.String paramName)
                                throws java.lang.IllegalArgumentException

Returns the value for this configuration parameter.

Parameters:

paramName - a valid configuration parameter, one of the String constants in this class.

Returns:

the configuration value.

Throws:

java.lang.IllegalArgumentException - if the paramName is invalid.

toString

public java.lang.String toString()

Display configuration values.

Overrides:

toString in class java.lang.Object