org.apache.tephra.persist

Class TransactionSnapshot

java.lang.Object

org.apache.tephra.persist.TransactionSnapshot

All Implemented Interfaces:

TransactionVisibilityState

public class TransactionSnapshot
extends Object
implements TransactionVisibilityState

Represents an in-memory snapshot of the full transaction state.

Constructor Summary

Constructors

Constructor and Description
TransactionSnapshot(long timestamp, long readPointer, long writePointer, Collection<Long> invalid, NavigableMap<Long,TransactionManager.InProgressTx> inProgress) Creates an instance of TransactionSnapshot with the given transaction state
TransactionSnapshot(long timestamp, long readPointer, long writePointer, Collection<Long> invalid, NavigableMap<Long,TransactionManager.InProgressTx> inProgress, Map<Long,Set<ChangeId>> committing, Map<Long,Set<ChangeId>> committed) Creates an instance of TransactionSnapshot with the given transaction state

Method Summary

Modifier and Type	Method and Description
static TransactionSnapshot	copyFrom(long snapshotTime, long readPointer, long writePointer, InvalidTxList invalidTxList, NavigableMap<Long,TransactionManager.InProgressTx> inProgress, Map<Long,TransactionManager.ChangeSet> committing, NavigableMap<Long,TransactionManager.ChangeSet> committed) Creates a new TransactionSnapshot instance with copies of all of the individual collections.
boolean	equals(Object obj) Checks that this instance matches another TransactionSnapshot instance.
Map<Long,Set<ChangeId>>	getCommittedChangeSets() Returns a map of transaction write pointer to set of changed row keys for transaction that had successfully called InMemoryTransactionManager.commit(Transaction) at the time of the snapshot.
Map<Long,Set<ChangeId>>	getCommittingChangeSets() Returns a map of transaction write pointer to sets of changed row keys for transactions that had called InMemoryTransactionManager.canCommit(Transaction, Collection) but not yet called InMemoryTransactionManager.commit(Transaction) at the time of the snapshot.
NavigableMap<Long,TransactionManager.InProgressTx>	getInProgress() Returns the map of write pointers to in-progress transactions at the time of the snapshot.
Collection<Long>	getInvalid() Returns the list of invalid write pointers at the time of the snapshot.
long	getReadPointer() Returns the read pointer at the time of the snapshot.
long	getTimestamp() Returns the timestamp from when this snapshot was created.
long	getVisibilityUpperBound()
long	getWritePointer() Returns the next write pointer at the time of the snapshot.
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

TransactionSnapshot

public TransactionSnapshot(long timestamp,
                           long readPointer,
                           long writePointer,
                           Collection<Long> invalid,
                           NavigableMap<Long,TransactionManager.InProgressTx> inProgress,
                           Map<Long,Set<ChangeId>> committing,
                           Map<Long,Set<ChangeId>> committed)

Creates an instance of TransactionSnapshot with the given transaction state

Parameters:

timestamp - timestamp, in millis, that the snapshot was taken

readPointer - current transaction read pointer

writePointer - current transaction write pointer

invalid - current list of invalid write pointer; must be sorted

inProgress - current map of in-progress write pointers to expiration timestamps

committing - current map of write pointers to change sets which have passed canCommit() but not yet committed

committed - current map of write pointers to change sets which have committed

TransactionSnapshot

public TransactionSnapshot(long timestamp,
                           long readPointer,
                           long writePointer,
                           Collection<Long> invalid,
                           NavigableMap<Long,TransactionManager.InProgressTx> inProgress)

Creates an instance of TransactionSnapshot with the given transaction state

Parameters:

timestamp - timestamp, in millis, that the snapshot was taken

readPointer - current transaction read pointer

writePointer - current transaction write pointer

invalid - current list of invalid write pointer; must be sorted

inProgress - current map of in-progress write pointers to expiration timestamps

Method Detail

getTimestamp

public long getTimestamp()

Description copied from interface: TransactionVisibilityState

Returns the timestamp from when this snapshot was created.

Specified by:

getTimestamp in interface TransactionVisibilityState

getReadPointer

public long getReadPointer()

Description copied from interface: TransactionVisibilityState

Returns the read pointer at the time of the snapshot.

Specified by:

getReadPointer in interface TransactionVisibilityState

getWritePointer

public long getWritePointer()

Description copied from interface: TransactionVisibilityState

Returns the next write pointer at the time of the snapshot.

Specified by:

getWritePointer in interface TransactionVisibilityState

getInvalid

public Collection<Long> getInvalid()

Description copied from interface: TransactionVisibilityState

Returns the list of invalid write pointers at the time of the snapshot.

Specified by:

getInvalid in interface TransactionVisibilityState

getInProgress

public NavigableMap<Long,TransactionManager.InProgressTx> getInProgress()

Description copied from interface: TransactionVisibilityState

Returns the map of write pointers to in-progress transactions at the time of the snapshot.

Specified by:

getInProgress in interface TransactionVisibilityState

getVisibilityUpperBound

public long getVisibilityUpperBound()

Specified by:

getVisibilityUpperBound in interface TransactionVisibilityState

Returns:

transaction id X such that any of the transactions newer than X might be invisible to some of the currently in-progress transactions or to those that will be started

NOTE: the returned tx id can be invalid.

getCommittingChangeSets

public Map<Long,Set<ChangeId>> getCommittingChangeSets()

Returns a map of transaction write pointer to sets of changed row keys for transactions that had called InMemoryTransactionManager.canCommit(Transaction, Collection) but not yet called InMemoryTransactionManager.commit(Transaction) at the time of the snapshot.

Returns:

a map of transaction write pointer to set of changed row keys.

getCommittedChangeSets

public Map<Long,Set<ChangeId>> getCommittedChangeSets()

Returns a map of transaction write pointer to set of changed row keys for transaction that had successfully called InMemoryTransactionManager.commit(Transaction) at the time of the snapshot.

Returns:

a map of transaction write pointer to set of changed row keys.

equals

public boolean equals(Object obj)

Checks that this instance matches another TransactionSnapshot instance. Note that the equality check ignores the snapshot timestamp value, but includes all other properties.

Overrides:

equals in class Object

Parameters:

obj - the other instance to check for equality.

Returns:

true if the instances are equal, false if not.

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

copyFrom

public static TransactionSnapshot copyFrom(long snapshotTime,
                                           long readPointer,
                                           long writePointer,
                                           InvalidTxList invalidTxList,
                                           NavigableMap<Long,TransactionManager.InProgressTx> inProgress,
                                           Map<Long,TransactionManager.ChangeSet> committing,
                                           NavigableMap<Long,TransactionManager.ChangeSet> committed)

Creates a new TransactionSnapshot instance with copies of all of the individual collections.

Parameters:

snapshotTime - timestamp, in millis, that the snapshot was taken

readPointer - current transaction read pointer

writePointer - current transaction write pointer

invalidTxList - current list of invalid write pointers

inProgress - current map of in-progress write pointers to expiration timestamps

committing - current map of write pointers to change sets which have passed canCommit() but not yet committed

committed - current map of write pointers to change sets which have committed

Returns:

a new TransactionSnapshot instance