co.cask.tephra.persist

Class TransactionSnapshot

java.lang.Object

co.cask.tephra.persist.TransactionSnapshot

public class TransactionSnapshot
extends Object

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, Map<Long,Set<ChangeId>> committing, Map<Long,Set<ChangeId>> committed)

Method Summary

Methods

Modifier and Type	Method and Description
static TransactionSnapshot	copyFrom(long snapshotTime, long readPointer, long writePointer, Collection<Long> invalid, NavigableMap<Long,TransactionManager.InProgressTx> inProgress, Map<Long,Set<ChangeId>> committing, NavigableMap<Long,Set<ChangeId>> 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.
Map<Long,TransactionManager.InProgressTx>	getInProgress() Returns the map of in-progress transaction write pointers 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)

Method Detail

getTimestamp

public long getTimestamp()

Returns the timestamp from when this snapshot was created.

getReadPointer

public long getReadPointer()

Returns the read pointer at the time of the snapshot.

getWritePointer

public long getWritePointer()

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

getInvalid

public Collection<Long> getInvalid()

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

getInProgress

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

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

Returns:

a map of write pointer to expiration timestamp (in milliseconds) for all transactions in-progress.

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.

getVisibilityUpperBound

public long getVisibilityUpperBound()

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.

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,
                           Collection<Long> invalid,
                           NavigableMap<Long,TransactionManager.InProgressTx> inProgress,
                           Map<Long,Set<ChangeId>> committing,
                           NavigableMap<Long,Set<ChangeId>> committed)

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

Parameters:

readPointer - current transaction read pointer

writePointer - current transaction write pointer

invalid - 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