co.cask.tephra.util

Class TxUtils

java.lang.Object

co.cask.tephra.util.TxUtils

public class TxUtils
extends Object

Utility methods supporting transaction operations.

Constructor Summary

Constructors

Constructor and Description
TxUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static Transaction	createDummyTransaction(TransactionSnapshot snapshot) Creates a "dummy" transaction based on the given snapshot's state.
static long	getFirstShortInProgress(Map<Long,TransactionManager.InProgressTx> inProgress) Returns the write pointer for the first "short" transaction that in the in-progress set, or Transaction.NO_TX_IN_PROGRESS if none.
static long	getMaxVisibleTimestamp(Transaction tx) Returns the maximum timestamp to use for time-range operations, based on the given transaction.
static long	getOldestVisibleTimestamp(Map<byte[],Long> ttlByFamily, Transaction tx) Returns the oldest visible timestamp for the given transaction, based on the TTLs configured for each column family.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TxUtils

public TxUtils()

Method Detail

getOldestVisibleTimestamp

public static long getOldestVisibleTimestamp(Map<byte[],Long> ttlByFamily,
                             Transaction tx)

Returns the oldest visible timestamp for the given transaction, based on the TTLs configured for each column family. If no TTL is set on any column family, the oldest visible timestamp will be 0.

Parameters:

ttlByFamily - A map of column family name to TTL value (in milliseconds)

tx - The current transaction

Returns:

The oldest timestamp that will be visible for the given transaction and TTL configuration

getMaxVisibleTimestamp

public static long getMaxVisibleTimestamp(Transaction tx)

Returns the maximum timestamp to use for time-range operations, based on the given transaction.

Parameters:

tx - The current transaction

Returns:

The maximum timestamp (exclusive) to use for time-range operations

createDummyTransaction

public static Transaction createDummyTransaction(TransactionSnapshot snapshot)

Creates a "dummy" transaction based on the given snapshot's state. This is not a "real" transaction in the sense that it has not been started, data should not be written with it, and it cannot be committed. However, this can still be useful for filtering data according to the snapshot's state. Instead of the actual write pointer from the snapshot, however, we use Long.MAX_VALUE to avoid mis-identifying any cells as being written by this transaction (and therefore visible).

getFirstShortInProgress

public static long getFirstShortInProgress(Map<Long,TransactionManager.InProgressTx> inProgress)

Returns the write pointer for the first "short" transaction that in the in-progress set, or Transaction.NO_TX_IN_PROGRESS if none.