public class EnvironmentMutableConfig
extends java.lang.Object
implements java.lang.Cloneable
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 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 = myEnvHandle.getMutableConfig(); mutableConfig.setTxnNoSync(true); myEnvHandle.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.
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 thread for the environment. EnvironmentMutableConfig mutableConfig = myEnvHandle.getMutableConfig(); mutableConfig.setConfigParam("je.env.runCleaner", "false"); myEnvHandle.setMutableConfig(mutableConfig);
The environment-wide mutable properties are listed below. These
properties are accessed using the setConfigParam(java.lang.String, java.lang.String)
and getConfigParam(java.lang.String)
methods, as shown in the example above, using the property
names listed below. In some cases setter and getter methods are also
available.
setCacheSize(long)
, getCacheSize()
)setCachePercent(int)
,
getCachePercent()
)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 EnvironmentConfigModifier and Type | Field and Description |
---|---|
protected long |
cacheSize |
protected java.util.Properties |
props |
Constructor and Description |
---|
EnvironmentMutableConfig()
An instance created using the default constructor is initialized with
the system's default settings.
|
Modifier and Type | Method and Description |
---|---|
protected java.lang.Object |
clone() |
int |
getCachePercent()
Returns the percentage value used in the JE cache size calculation.
|
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.
|
ReplicaConsistencyPolicy |
getConsistencyPolicy() |
Durability |
getDurability() |
ExceptionListener |
getExceptionListener()
Returns the exception listener, if set.
|
int |
getNumExplicitlySetParams()
Testing support
|
boolean |
getTxnNoSync()
Returns true if the database environment is configured for asynchronous
transactions.
|
boolean |
getTxnWriteNoSync()
Returns true if the database environment is configured for transactions
which write but do not flush the log.
|
void |
setCachePercent(int percent)
By default, JE sets its cache size proportionally to the JVM
memory.
|
void |
setCacheSize(long totalBytes)
Configures the memory available to the database system, in bytes.
|
void |
setConfigParam(java.lang.String paramName,
java.lang.String value)
Validates the value prescribed for the configuration parameter; if it is
valid, the value is set in the configuration.
|
void |
setConsistencyPolicy(ReplicaConsistencyPolicy consistencyPolicy) |
void |
setDurability(Durability durability) |
void |
setExceptionListener(ExceptionListener exceptionListener)
Sets the exception listener for an Environment.
|
void |
setTxnNoSync(boolean noSync)
Configures the database environment for asynchronous transactions.
|
void |
setTxnWriteNoSync(boolean writeNoSync)
Configures the database environment for transactions which write but do
not flush the log.
|
java.lang.String |
toString()
Display configuration values.
|
public EnvironmentMutableConfig()
public void setTxnNoSync(boolean noSync)
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.
DatabaseException
- if a failure occurs.public boolean getTxnNoSync()
public void setTxnWriteNoSync(boolean writeNoSync)
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.
DatabaseException
- if a failure occurs.public boolean getTxnWriteNoSync()
public void setDurability(Durability durability)
durability
- the durability definitionpublic Durability getDurability()
public void setConsistencyPolicy(ReplicaConsistencyPolicy consistencyPolicy)
consistencyPolicy
- the consistency definitionpublic ReplicaConsistencyPolicy getConsistencyPolicy()
public void setCacheSize(long totalBytes) throws java.lang.IllegalArgumentException
Equivalent to setting the je.maxMemory property in the je.properties file. The system will evict database objects when it comes within a prescribed margin of the limit.
By default, JE sets the cache size to:
je.maxMemoryPercent * JVM maximum memory
where JVM maximum memory is specified by the JVM -Xmx flag. However, calling setCacheSize() with a non-zero value overrides the percentage based calculation and sets the cache size explicitly.
Note that the log buffer cache may be cleared if the cache size is changed after the environment has been opened.
If setSharedCache(true) is called, setCacheSize and setCachePercent specify the total size of the shared cache, and changing these parameters will change the size of the shared cache.
totalBytes
- The memory available to the database system, in bytes.java.lang.IllegalArgumentException
- if an invalid parameter was specified.DatabaseException
- if a failure occurs.public long getCacheSize()
public void setCachePercent(int percent) throws java.lang.IllegalArgumentException
By default, JE sets its cache size proportionally to the JVM memory. This formula is used:
je.maxMemoryPercent * JVM maximum memory
where JVM maximum memory is specified by the JVM -Xmx flag. setCachePercent() specifies the percentage used and is equivalent to setting the je.maxMemoryPercent property in the je.properties file.
Calling setCacheSize() with a non-zero value overrides the percentage based calculation and sets the cache size explicitly.
Note that the log buffer cache may be cleared if the cache size is changed after the environment has been opened.
If setSharedCache(true) is called, setCacheSize and setCachePercent specify the total size of the shared cache, and changing these parameters will change the size of the shared cache.
percent
- The percent of JVM memory to allocate to the JE cache.java.lang.IllegalArgumentException
- if an invalid parameter was specified.DatabaseException
- if a failure occurs.public int getCachePercent()
public void setExceptionListener(ExceptionListener exceptionListener)
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.
exceptionListener
- the callback to be executed when an exception
occurs.public ExceptionListener getExceptionListener()
public void setConfigParam(java.lang.String paramName, java.lang.String value) throws java.lang.IllegalArgumentException
paramName
- The name of the configuration parameter. See
the sample je.properties file for descriptions of all parameters.value
- The value for this configuration parameter.java.lang.IllegalArgumentException
- if an invalid parameter was specified.DatabaseException
- if a failure occurs.public java.lang.String getConfigParam(java.lang.String paramName) throws java.lang.IllegalArgumentException
paramName
- Name of the requested parameter.java.lang.IllegalArgumentException
- if the configParamName is invalid.protected java.lang.Object clone() throws java.lang.CloneNotSupportedException
clone
in class java.lang.Object
java.lang.CloneNotSupportedException
public int getNumExplicitlySetParams()
public java.lang.String toString()
toString
in class java.lang.Object