org.neo4j.storageengine.api

Enum TransactionApplicationMode

java.lang.Object

java.lang.Enum<TransactionApplicationMode>

org.neo4j.storageengine.api.TransactionApplicationMode

All Implemented Interfaces:

Serializable, Comparable<TransactionApplicationMode>

public enum TransactionApplicationMode
extends Enum<TransactionApplicationMode>

Mode of applying transactions. Depending on how transaction state have been built, additional work may need to be performed during application of it.

Enum Constant Summary

Enum Constants

Enum Constant and Description
EXTERNAL Transaction that comes from an external source and consists only of commands, i.e.
INTERNAL Transaction that is created in the "normal" way and has changed transaction state, which goes to commit and produces commands from that.
RECOVERY Transaction that is recovered, where commands are read, much like EXTERNAL, but should be applied differently where extra care should be taken to ensure idempotency.
REVERSE_RECOVERY Transaction that is recovered during a phase of reverse recovery in order to rewind neo store back to a state where forward recovery then can commence from.

Method Summary

Modifier and Type	Method and Description
boolean	needsAuxiliaryStores()
boolean	needsCacheInvalidationOnUpdates()
boolean	needsHighIdTracking()
boolean	needsIdempotencyChecks()
static TransactionApplicationMode	valueOf(String name) Returns the enum constant of this type with the specified name.
static TransactionApplicationMode[]	values() Returns an array containing the constants of this enum type, in the order they are declared.
org.neo4j.kernel.impl.transaction.command.Command.Version	version()

Methods inherited from class java.lang.Enum

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

INTERNAL

public static final TransactionApplicationMode INTERNAL

Transaction that is created in the "normal" way and has changed transaction state, which goes to commit and produces commands from that. Such a transaction is able to alter cache since it has all such high level information directly from the transaction state.

EXTERNAL

public static final TransactionApplicationMode EXTERNAL

Transaction that comes from an external source and consists only of commands, i.e. it may not contain enough information to f.ex. update cache, but applies to the store just like an internal transaction does.

RECOVERY

public static final TransactionApplicationMode RECOVERY

Transaction that is recovered, where commands are read, much like EXTERNAL, but should be applied differently where extra care should be taken to ensure idempotency. This is because a recovered transaction may have already been applied previously to the store.

REVERSE_RECOVERY

public static final TransactionApplicationMode REVERSE_RECOVERY

Transaction that is recovered during a phase of reverse recovery in order to rewind neo store back to a state where forward recovery then can commence from. Rewinding the store back to the point if the last checkpoint will allow for correct updates to indexes, because indexes reads from a mix of log and store to produce its updates.

Method Detail

values

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

Returns:

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

valueOf

public static TransactionApplicationMode 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

needsHighIdTracking

public boolean needsHighIdTracking()

Returns:

whether or not applying a transaction need to track and update high ids of underlying stores.

needsCacheInvalidationOnUpdates

public boolean needsCacheInvalidationOnUpdates()

Returns:

whether or not applying a transaction need to do additional work of invalidating affected caches.

needsIdempotencyChecks

public boolean needsIdempotencyChecks()

Returns:

whether or not applying a transaction need to be extra cautious about idempotency.

needsAuxiliaryStores

public boolean needsAuxiliaryStores()

Returns:

whether or not to include auxiliary stores, such as indexing, counts and statistics.

version

public org.neo4j.kernel.impl.transaction.command.Command.Version version()

Returns:

which version of commands to apply, where some commands have before/after versions.