org.apache.cassandra.db.memtable

Class AbstractAllocatorMemtable

java.lang.Object

org.apache.cassandra.db.memtable.AbstractMemtable

org.apache.cassandra.db.memtable.AbstractMemtableWithCommitlog

org.apache.cassandra.db.memtable.AbstractAllocatorMemtable

All Implemented Interfaces:

java.lang.Comparable<Memtable>, Memtable, UnfilteredSource

Direct Known Subclasses:

ShardedSkipListMemtable, SkipListMemtable

public abstract class AbstractAllocatorMemtable
extends AbstractMemtableWithCommitlog

A memtable that uses memory tracked and maybe allocated via a MemtableAllocator from a MemtablePool. Provides methods of memory tracking and triggering flushes when the relevant limits are reached.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.cassandra.db.memtable.AbstractMemtable

AbstractMemtable.AbstractFlushablePartitionSet<P extends Partition>, AbstractMemtable.ColumnsCollector, AbstractMemtable.StatsCollector

Nested classes/interfaces inherited from interface org.apache.cassandra.db.memtable.Memtable

Memtable.Factory, Memtable.FlushablePartitionSet<P extends Partition>, Memtable.LastCommitLogPosition, Memtable.MemoryUsage, Memtable.Owner

Field Summary

Fields

Modifier and Type	Field and Description
protected MemtableAllocator	allocator
protected ClusteringComparator	initialComparator
static MemtablePool	MEMORY_POOL
protected Memtable.Owner	owner

Fields inherited from class org.apache.cassandra.db.memtable.AbstractMemtable

columnsCollector, currentOperations, metadata, minLocalDeletionTime, minTimestamp, statsCollector

Constructor Summary

Constructors

Constructor and Description
AbstractAllocatorMemtable(java.util.concurrent.atomic.AtomicReference<CommitLogPosition> commitLogLowerBound, TableMetadataRef metadataRef, Memtable.Owner owner)

Method Summary

Modifier and Type	Method and Description
void	addMemoryUsageTo(Memtable.MemoryUsage stats) Add this memtable's used memory to the given usage object.
void	discard() This memtable is no longer in use or required for outstanding flushes or operations.
protected abstract Memtable.Factory	factory()
static Future<java.lang.Boolean>	flushLargestMemtable() Finds the largest memtable, as a percentage of *either* on- or off-heap memory limits, and immediately queues it for flushing.
MemtableAllocator	getAllocator()
void	localRangesUpdated() Called when the known ranges have been updated and owner.localRangeSplits() may return different values.
void	markExtraOffHeapUsed(long additionalSpace, OpOrder.Group opGroup) Adjust the used off-heap space by the given size (e.g.
void	markExtraOnHeapUsed(long additionalSpace, OpOrder.Group opGroup) Adjust the used on-heap space by the given size (e.g.
void	metadataUpdated() Called when the table's metadata is updated.
void	performSnapshot(java.lang.String snapshotName) If the memtable needs to do some special action for snapshots (e.g.
boolean	shouldSwitch(ColumnFamilyStore.FlushReason reason) Decides whether the memtable should be switched/flushed for the passed reason.
void	switchOut(OpOrder.Barrier writeBarrier, java.util.concurrent.atomic.AtomicReference<CommitLogPosition> commitLogUpperBound) Called to tell the memtable that it is being switched out and will be flushed (or dropped) and discarded.
java.lang.String	toString()

Methods inherited from class org.apache.cassandra.db.memtable.AbstractMemtableWithCommitlog

accepts, getApproximateCommitLogLowerBound, getCommitLogLowerBound, getFinalCommitLogUpperBound, mayContainDataBefore

Methods inherited from class org.apache.cassandra.db.memtable.AbstractMemtable

getMinLocalDeletionTime, getMinTimestamp, metadata, operationCount, updateMin, updateMin

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.cassandra.db.memtable.Memtable

compareTo, getFlushSet, getLiveDataSize, getMemoryUsage, isClean, newMemoryUsage, partitionCount, put

Methods inherited from interface org.apache.cassandra.db.rows.UnfilteredSource

partitionIterator, rowIterator, rowIterator

Field Detail

MEMORY_POOL

public static final MemtablePool MEMORY_POOL

owner

protected final Memtable.Owner owner

allocator

protected final MemtableAllocator allocator

initialComparator

protected final ClusteringComparator initialComparator

Constructor Detail

AbstractAllocatorMemtable

public AbstractAllocatorMemtable(java.util.concurrent.atomic.AtomicReference<CommitLogPosition> commitLogLowerBound,
                                 TableMetadataRef metadataRef,
                                 Memtable.Owner owner)

Method Detail

getAllocator

public MemtableAllocator getAllocator()

shouldSwitch

public boolean shouldSwitch(ColumnFamilyStore.FlushReason reason)

Description copied from interface: Memtable

Decides whether the memtable should be switched/flushed for the passed reason. Normally this will return true, but e.g. persistent memtables may choose not to flush. Returning false will trigger further action for some reasons: - SCHEMA_CHANGE will be followed by metadataUpdated(). - OWNED_RANGES_CHANGE will be followed by localRangesUpdated(). - SNAPSHOT will be followed by performSnapshot(). - STREAMING/REPAIR will be followed by creating a FlushSet for the streamed/repaired ranges. This data will be used to create sstables, which will be streamed and then deleted. This will not be called to perform truncation or drop (in that case the memtable is unconditionally dropped), but a flush may nevertheless be requested in that case to prepare a snapshot.

metadataUpdated

public void metadataUpdated()

Description copied from interface: Memtable

Called when the table's metadata is updated. The memtable's metadata reference now points to the new version. This will not be called if {@link #shouldSwitch)(SCHEMA_CHANGE) returns true, as the memtable will be swapped out instead.

localRangesUpdated

public void localRangesUpdated()

Description copied from interface: Memtable

Called when the known ranges have been updated and owner.localRangeSplits() may return different values. This will not be called if {@link #shouldSwitch)(OWNED_RANGES_CHANGE) returns true, as the memtable will be swapped out instead.

performSnapshot

public void performSnapshot(java.lang.String snapshotName)

Description copied from interface: Memtable

If the memtable needs to do some special action for snapshots (e.g. because it is persistent and does not want to flush), it should return false on the above with reason SNAPSHOT and implement this method.

factory

protected abstract Memtable.Factory factory()

switchOut

public void switchOut(OpOrder.Barrier writeBarrier,
                      java.util.concurrent.atomic.AtomicReference<CommitLogPosition> commitLogUpperBound)

Description copied from interface: Memtable

Called to tell the memtable that it is being switched out and will be flushed (or dropped) and discarded. Will be followed by a Memtable.getFlushSet(org.apache.cassandra.db.PartitionPosition, org.apache.cassandra.db.PartitionPosition) call (if the table is not truncated or dropped), and a Memtable.discard().

Specified by:

switchOut in interface Memtable

Overrides:

switchOut in class AbstractMemtableWithCommitlog

Parameters:

writeBarrier - The barrier that will signal that all writes to this memtable have completed. That is, the point after which writes cannot be accepted by this memtable (it is permitted for writes before this barrier to go into the next; see Memtable.accepts(org.apache.cassandra.utils.concurrent.OpOrder.Group, org.apache.cassandra.db.commitlog.CommitLogPosition)).

commitLogUpperBound - The upper commit log position for this memtable. The value may be modified after this call and will match the next memtable's lower commit log bound.

discard

public void discard()

Description copied from interface: Memtable

This memtable is no longer in use or required for outstanding flushes or operations. All held memory must be released.

Specified by:

discard in interface Memtable

Overrides:

discard in class AbstractMemtableWithCommitlog

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

addMemoryUsageTo

public void addMemoryUsageTo(Memtable.MemoryUsage stats)

Description copied from interface: Memtable

Add this memtable's used memory to the given usage object. This can be used to retrieve a single memtable's usage as well as to combine the ones of related sstables (e.g. a table and its table-based secondary indexes).

markExtraOnHeapUsed

public void markExtraOnHeapUsed(long additionalSpace,
                                OpOrder.Group opGroup)

Description copied from interface: Memtable

Adjust the used on-heap space by the given size (e.g. to reflect memory used by a non-table-based index). This operation may block until enough memory is available in the memory pool.

Parameters:

additionalSpace - the number of allocated bytes

opGroup - write operation group, used to permit the operation to complete if it is needed to complete a flush to free space.

markExtraOffHeapUsed

public void markExtraOffHeapUsed(long additionalSpace,
                                 OpOrder.Group opGroup)

Description copied from interface: Memtable

Adjust the used off-heap space by the given size (e.g. to reflect memory used by a non-table-based index). This operation may block until enough memory is available in the memory pool.

Parameters:

additionalSpace - the number of allocated bytes

opGroup - write operation group, used to permit the operation to complete if it is needed to complete a flush to free space.

flushLargestMemtable

public static Future<java.lang.Boolean> flushLargestMemtable()

Finds the largest memtable, as a percentage of *either* on- or off-heap memory limits, and immediately queues it for flushing. If the memtable selected is flushed before this completes, no work is done.