com.sleepycat.db
Class TransactionConfig

java.lang.Object
  com.sleepycat.db.TransactionConfig

All Implemented Interfaces:

Cloneable

public class TransactionConfig

extends Object

implements Cloneable

Specifies the attributes of a database environment transaction.

Field Summary

static TransactionConfig

DEFAULT

Constructor Summary

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

Method Summary

boolean	getDegree2() Return if the transaction has been configured to have degree 2 isolation.
boolean	getDirtyRead() Return if the transaction is configured to perform dirty reads.
boolean	getNoSync() Return if the transaction is configured to not write or synchronously flush the log it when commits.
boolean	getNoWait() Return if the transaction is configured to not wait if a lock request cannot be immediately granted.
boolean	getSync() Return if the transaction is configured to not write or synchronously flush the log it when commits.
boolean	getWriteNoSync() Return if the transaction is configured to write but not synchronously flush the log it when commits.
void	setDegree2(boolean degree2) Configure this transaction to have degree 2 isolation.
void	setDirtyRead(boolean dirtyRead) Configure the transaction to perform dirty reads.
void	setNoSync(boolean txnNoSync) Configure the transaction to not write or synchronously flush the log it when commits.
void	setNoWait(boolean noWait) Configure the transaction to not wait if a lock request cannot be immediately granted.
void	setSync(boolean txnSync) Configure the transaction to write or synchronously flush the log it when commits.
void	setWriteNoSync(boolean txnWriteNoSync) Configure the transaction to write but not synchronously flush the log it when commits.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final TransactionConfig DEFAULT

Constructor Detail

TransactionConfig

public TransactionConfig()

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

Method Detail

setDegree2

public void setDegree2(boolean degree2)

Configure this transaction to have degree 2 isolation. This provides for cursor stability but not repeatable reads. Data items which have been previously read by this transaction may be deleted or modified by other transactions before this transaction completes.

The default is false for this class and the database environment.

getDegree2

public boolean getDegree2()

Return if the transaction has been configured to have degree 2 isolation.

Returns:

If the transaction has been configured to have degree 2 isolation.

setSync

public void setSync(boolean txnSync)

Configure the transaction to write or synchronously flush the log it when commits.

This behavior may be set for a database environment using the Environment.setMutableConfig method. Any value specified to this method overrides that setting.

The default is false for this class and true for the database environment.

If true is passed to both setSync and setNoSync, setSync will take precedence.

Parameters:

txnSync - If true, transactions exhibit all the ACID (atomicity, consistency, isolation, and durability) properties.

getSync

public boolean getSync()

Return if the transaction is configured to not write or synchronously flush the log it when commits.

Returns:

If the transaction is configured to not write or synchronously flush the log it when commits.

setWriteNoSync

public void setWriteNoSync(boolean txnWriteNoSync)

Configure the transaction to write but not synchronously flush the log it when commits.

This behavior may be set for a database environment using the Environment.setMutableConfig method. Any value specified to this method overrides that setting.

The default is false for this class and the database environment.

Parameters:

txnWriteNoSync - If true, transactions exhibit the ACI (atomicity, consistency, and isolation) properties, but not D (durability); that is, database integrity will be 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 log is checkpointed.

getWriteNoSync

public boolean getWriteNoSync()

Return if the transaction is configured to write but not synchronously flush the log it when commits.

Returns:

If the transaction is configured to not write or synchronously flush the log it when commits.

setNoSync

public void setNoSync(boolean txnNoSync)

Configure the transaction to not write or synchronously flush the log it when commits.

This behavior may be set for a database environment using the Environment.setMutableConfig method. Any value specified to this method overrides that setting.

The default is false for this class and the database environment.

Parameters:

txnNoSync - If true, 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.

getNoSync

public boolean getNoSync()

Return if the transaction is configured to not write or synchronously flush the log it when commits.

Returns:

If the transaction is configured to not write or synchronously flush the log it when commits.

setNoWait

public void setNoWait(boolean noWait)

Configure the transaction to not wait if a lock request cannot be immediately granted.

The default is false for this class and the database environment.

Parameters:

noWait - If true, transactions will not wait if a lock request cannot be immediately granted, instead DeadlockException will be thrown.

getNoWait

public boolean getNoWait()

Return if the transaction is configured to not wait if a lock request cannot be immediately granted.

Returns:

If the transaction is configured to not wait if a lock request cannot be immediately granted.

setDirtyRead

public void setDirtyRead(boolean dirtyRead)

Configure the transaction to perform dirty reads.

The default is false for this class and the database environment.

Parameters:

dirtyRead - If true, all read operations performed by the transaction may read modified but not yet committed data.

getDirtyRead

public boolean getDirtyRead()

Return if the transaction is configured to perform dirty reads.

Returns:

If the transaction is configured to perform dirty reads.