Package com.palantir.atlasdb.transaction.api

Interface LockWatchingCache

All Known Implementing Classes:

NoOpLockWatchingCache

public interface LockWatchingCache

Method Summary

Modifier and Type	Method	Description
Map<Cell,GuardedValue>	getCached(TableReference tableRef, Set<Cell> reads)	Given a table and a set of cells, the cache returns a map containing the latest cached GuardedValues for cells present in the cache.
TransactionLockWatchingCacheView	getView(long startTimestamp, com.palantir.lock.watch.LockWatchStateUpdate lockWatchState)	Creates a view of the cache for a transaction, based on the start timestamp and the lock watch state.
void	maybeCacheCommittedWrites(TableReference tableRef, Map<Cell,byte[]> writes)	After a transaction has committed, this notifies the cache that the writes can be cached, if desired.
void	maybeCacheEntriesRead(TableReference tableRef, Map<Cell,byte[]> writes, com.palantir.lock.watch.LockWatchStateUpdate lockWatchState)	A transaction can attempt to cache entries read during the transaction using this method.

Method Detail

getCached

Map<Cell,GuardedValue> getCached(TableReference tableRef,
                                       Set<Cell> reads)

Given a table and a set of cells, the cache returns a map containing the latest cached GuardedValues for cells present in the cache.

Parameters:

tableRef - table to read from

reads - set of cells to read

Returns:

Cached values that are guaranteed to be the latest visible entries to the transaction making the request if the GuardedValue's timestamp matches the transaction's lock watch state

maybeCacheCommittedWrites

void maybeCacheCommittedWrites(TableReference tableRef,
                               Map<Cell,byte[]> writes)

After a transaction has committed, this notifies the cache that the writes can be cached, if desired.

Parameters:

tableRef - the table to which the transaction wrote

writes - actual writes

maybeCacheEntriesRead

void maybeCacheEntriesRead(TableReference tableRef,
                           Map<Cell,byte[]> writes,
                           com.palantir.lock.watch.LockWatchStateUpdate lockWatchState)

A transaction can attempt to cache entries read during the transaction using this method. The implementation of the LockWatchStateUpdate must correctly arbitrate which of the passed entries are safe to cache.

Parameters:

tableRef - table to cache entries for

writes - entries read by the transaction

lockWatchState - lock watch state at the start of the transaction that read the entries

getView

TransactionLockWatchingCacheView getView(long startTimestamp,
                                         com.palantir.lock.watch.LockWatchStateUpdate lockWatchState)

Creates a view of the cache for a transaction, based on the start timestamp and the lock watch state.

Parameters:

startTimestamp - of the transaction

lockWatchState - returned from the StartTransactionWithWatchesResponse

Returns:

view of the cache