Package com.sleepycat.je

Enum Durability.SyncPolicy

java.lang.Object

java.lang.Enum<Durability.SyncPolicy>

com.sleepycat.je.Durability.SyncPolicy

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<Durability.SyncPolicy>

Enclosing class:

Durability

public static enum Durability.SyncPolicy
extends java.lang.Enum<Durability.SyncPolicy>

Defines the synchronization policy to be used when committing a transaction. High levels of synchronization offer a greater guarantee that the transaction is persistent to disk, but trade that off for lower performance.

Enum Constant Summary

Enum Constants

Enum Constant	Description
NO_SYNC	Do not write or synchronously flush the log on transaction commit.
SYNC	Write and synchronously flush the log on transaction commit.
WRITE_NO_SYNC	Write but do not synchronously flush the log on transaction commit.

Method Summary

Modifier and Type	Method	Description
static Durability.SyncPolicy	valueOf(java.lang.String name)	Returns the enum constant of this type with the specified name.
static Durability.SyncPolicy[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

SYNC

public static final Durability.SyncPolicy SYNC

Write and synchronously flush the log on transaction commit. Transactions exhibit all the ACID (atomicity, consistency, isolation, and durability) properties.

This is the default for a non-replicated environment.

See Also:

I/O Statistics: Fsync and Group Commit

NO_SYNC

public static final Durability.SyncPolicy NO_SYNC

Do not write or synchronously flush the log on transaction commit. 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 is the default for a replicated environment.

See Also:

I/O Statistics: Log Buffers, I/O Statistics: The Write Queue

WRITE_NO_SYNC

public static final Durability.SyncPolicy WRITE_NO_SYNC

Write but do not synchronously flush the log on transaction commit. 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.

See Also:

I/O Statistics: Fsync and Group Commit

Method Detail

values

public static Durability.SyncPolicy[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Durability.SyncPolicy c : Durability.SyncPolicy.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Durability.SyncPolicy valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null