org.apache.ignite.configuration

Enum WALMode

java.lang.Object

java.lang.Enum<WALMode>

org.apache.ignite.configuration.WALMode

All Implemented Interfaces:

Serializable, Comparable<WALMode>

public enum WALMode
extends Enum<WALMode>

WAL Mode. This enum defines crash recovery guarantees when Ignite persistence is enabled.

Enum Constant Summary

Enum Constants

Enum Constant and Description
BACKGROUND Background mode.
DEFAULT Deprecated. This mode is no longer default and left here only for API compatibility. It is equivalent to the FSYNC mode.
FSYNC FSYNC mode: full-sync disk writes.
LOG_ONLY Log only mode: flushes application buffers.
NONE WAL is disabled.

Method Summary

Modifier and Type	Method and Description
static @Nullable WALMode	fromOrdinal(int ord) Efficiently gets enumerated value from its ordinal.
static WALMode	valueOf(String name) Returns the enum constant of this type with the specified name.
static WALMode[]	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

FSYNC

public static final WALMode FSYNC

FSYNC mode: full-sync disk writes. These writes survive power loss scenarios. When a control is returned from the transaction commit operation, the changes are guaranteed to be persisted to disk according to the transaction write synchronization mode.

LOG_ONLY

public static final WALMode LOG_ONLY

Log only mode: flushes application buffers. These writes survive process crash. When a control is returned from the transaction commit operation, the changes are guaranteed to be forced to the OS buffer cache. It's up to the OS to decide when to flush its caches to disk.

BACKGROUND

public static final WALMode BACKGROUND

Background mode. Does not force application's buffer flush. Last updates may be lost in case of a process crash.

NONE

public static final WALMode NONE

WAL is disabled. Data is guaranteed to be persisted on disk only in case of graceful cluster shutdown using IgniteCluster.state(ClusterState) method. If an Ignite node is terminated in NONE mode abruptly, it is likely that the data stored on disk is corrupted and work directory will need to be cleared for a node restart.

DEFAULT

@Deprecated
public static final WALMode DEFAULT

Deprecated. This mode is no longer default and left here only for API compatibility. It is equivalent to the FSYNC mode.

Default mode: full-sync disk writes. These writes survive power loss scenarios. When a control is returned from the transaction commit operation, the changes are guaranteed to be persisted to disk according to the transaction write synchronization mode.

Method Detail

values

public static WALMode[] 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 (WALMode c : WALMode.values())
    System.out.println(c);

Returns:

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

valueOf

public static WALMode valueOf(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:

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

NullPointerException - if the argument is null

fromOrdinal

@Nullable
public static @Nullable WALMode fromOrdinal(int ord)

Efficiently gets enumerated value from its ordinal.

Parameters:

ord - Ordinal value.

Returns:

Enumerated value or null if ordinal out of range.