Package org.apache.ignite.internal.pagemem

Class PageMemoryImpl

java.lang.Object

org.apache.ignite.internal.pagemem.PageMemoryImpl

All Implemented Interfaces:

PageMemory

public class PageMemoryImpl
extends Object
implements PageMemory

Page header structure is described by the following diagram. When page is not allocated (in a free list):

 +--------+------------------------------------------------------+
 |8 bytes |         PAGE_SIZE + PAGE_OVERHEAD - 8 bytes          |
 +--------+------------------------------------------------------+
 |Next ptr|                      Page data                       |
 +--------+------------------------------------------------------+
 

When page is allocated and is in use:

 +------------------+--------+--------+---------+---------+----+--------+--------+----------------------+
 |     8 bytes      |8 bytes |4 bytes |4 bytes  |4 bytes  |4 b |8 bytes |8 bytes |       PAGE_SIZE      |
 +------------------+--------+--------+---------+---------+----+--------+--------+----------------------+
 | Marker/Timestamp |Rel ptr |Page ID | (align) |Store ID |PIN | LOCK   |TMP BUF |       Page data      |
 +------------------+--------+--------+---------+---------+----+--------+--------+----------------------+
 

Note that first 8 bytes of page header are used either for page marker or for next relative pointer depending on whether the page is in use or not.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	PageMemoryImpl.ThrottlingPolicy	Throttling enabled and its type enum.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	CHECKPOINT_POOL_OVERFLOW_ERROR_MSG	Checkpoint pool overflow error message.
static final boolean	DFLT_DELAYED_REPLACED_PAGE_WRITE
static final boolean	DFLT_LOADED_PAGES_BACKWARD_SHIFT_MAP
static final Long	DFLT_MAX_CHECKPOINTING_PAGE_BUFFER_SIZE	Default minimum checkpointing page buffer size (may be adjusted by Ignite).
static final Long	DFLT_MIN_CHECKPOINTING_PAGE_BUFFER_SIZE	Minimum checkpointing page buffer size (may be adjusted by Ignite).
static final int	PAGE_LOCK_OFFSET	Page lock offset.
static final int	PAGE_OVERHEAD	8b Marker/timestamp 8b Relative pointer 4b Page ID 4b Store ID 4b Pin count 8b Lock 8b Temporary buffer
static final int	RANDOM_PAGES_EVICT_NUM	Number of random pages that will be picked for eviction.

Fields inherited from interface org.apache.ignite.internal.pagemem.PageMemory

ANY_TAG

Constructor Summary

Constructors

Constructor	Description
PageMemoryImpl(String name, long maximumSize, int pageSize, int concurrencyLevel, DirectMemoryProvider directMemoryProvider, PageStoreManager storeMgr, IgnitePredicate<Long> evictablePagePredicate, IgniteClosure<Long,Integer> tagReader, ExecutorService asyncRunner, IgniteLogger log, DataRegionMetrics memMetrics)	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
long	acquirePage(int grpId, int pageId, int tag)	Gets the page absolute pointer associated with the given page ID.
long	acquirePage(int grpId, int pageId, int tag, boolean restore)	Gets the page absolute pointer associated with the given page ID.
int	allocatePage(int grpId, int tag)	Allocates a page from the space for the given partition ID and the given flags.
void	beginCheckpoint()	Begins a checkpoint.
Collection<Long>	dirtyPages()	Gets a collection of all pages currently marked as dirty.
void	finishCheckpoint()	Finishes a checkpoint.
boolean	isDirty(int grpId, int pageId, long page)
int	metaPageId(int grpId)	Gets or allocates metadata page for specified grpId.
DataRegionMetrics	metrics()
long	readLock(int grpId, int pageId, long absPtr, int tag, boolean touch)
void	readUnlock(int grpId, int pageId, long page)	Releases locked page.
void	reduceMemoryFootprint()	Reduces memory footprint.
void	releasePage(int grpId, int pageId, long page)
void	runCheckpoint()	Runs a checkpoint.
boolean	safeToUpdate()	Heuristic method which allows a thread to check if it safe to start memory struture modifications in regard with checkpointing.
void	start()	Start page memory.
void	startStore(int grpId, int metaPageTag, Path path, boolean restorationMode)	Starts the store with the specified ID.
void	stop()	Stop page memory.
void	stopStore(int grpId, boolean freePages)	Stops the store with the specified ID.
long	totalPages()	Total pages can be placed to memory.
long	tryWriteLock(int grpId, int pageId, long page, int tag)
long	writeLock(int grpId, int pageId, long page, int tag)
void	writeUnlock(int grpId, int pageId, long page, boolean modified, int tag)

Methods inherited from class java.lang.Object

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

Field Details

PAGE_LOCK_OFFSET

public static final int PAGE_LOCK_OFFSET

Page lock offset.

See Also:

• Constant Field Values

PAGE_OVERHEAD

public static final int PAGE_OVERHEAD

8b Marker/timestamp 8b Relative pointer 4b Page ID 4b Store ID 4b Pin count 8b Lock 8b Temporary buffer

See Also:

• Constant Field Values

RANDOM_PAGES_EVICT_NUM

public static final int RANDOM_PAGES_EVICT_NUM

Number of random pages that will be picked for eviction.

See Also:

• Constant Field Values

DFLT_DELAYED_REPLACED_PAGE_WRITE

public static final boolean DFLT_DELAYED_REPLACED_PAGE_WRITE

See Also:

• IgniteSystemProperties#IGNITE_DELAYED_REPLACED_PAGE_WRITE
• Constant Field Values

DFLT_LOADED_PAGES_BACKWARD_SHIFT_MAP

public static final boolean DFLT_LOADED_PAGES_BACKWARD_SHIFT_MAP

See Also:

• IgniteSystemProperties#IGNITE_LOADED_PAGES_BACKWARD_SHIFT_MAP
• Constant Field Values

CHECKPOINT_POOL_OVERFLOW_ERROR_MSG

public static final String CHECKPOINT_POOL_OVERFLOW_ERROR_MSG

Checkpoint pool overflow error message.

See Also:

• Constant Field Values

DFLT_MIN_CHECKPOINTING_PAGE_BUFFER_SIZE

public static final Long DFLT_MIN_CHECKPOINTING_PAGE_BUFFER_SIZE

Minimum checkpointing page buffer size (may be adjusted by Ignite).

DFLT_MAX_CHECKPOINTING_PAGE_BUFFER_SIZE

public static final Long DFLT_MAX_CHECKPOINTING_PAGE_BUFFER_SIZE

Default minimum checkpointing page buffer size (may be adjusted by Ignite).

Constructor Details

PageMemoryImpl

public PageMemoryImpl(String name,
 long maximumSize,
 int pageSize,
 int concurrencyLevel,
 DirectMemoryProvider directMemoryProvider,
 PageStoreManager storeMgr,
 IgnitePredicate<Long> evictablePagePredicate,
 IgniteClosure<Long,Integer> tagReader,
 ExecutorService asyncRunner,
 IgniteLogger log,
 DataRegionMetrics memMetrics)

Constructs a new instance.

Parameters:

name -

initialSize -

maximumSize -

pageSize -

concurrencyLevel -

tagInitValue -

directMemoryProvider -

storeMgr -

evictablePagePredicate -

tagReader -

asyncRunner -

log -

memMetrics -

Method Details

start

public void start()
           throws IgniteCheckedException

Description copied from interface: PageMemory

Start page memory.

Specified by:

start in interface PageMemory

Throws:

IgniteCheckedException

stop

public void stop()
          throws IgniteCheckedException

Description copied from interface: PageMemory

Stop page memory.

Specified by:

stop in interface PageMemory

Throws:

IgniteCheckedException

startStore

public void startStore(int grpId,
 int metaPageTag,
 Path path,
 boolean restorationMode)
                throws IgniteCheckedException

Description copied from interface: PageMemory

Starts the store with the specified ID.

Specified by:

startStore in interface PageMemory

Parameters:

grpId - Group ID.

metaPageTag - Meta-page tag.

path - Store path.

restorationMode - Flag indicating restoration mode.

Throws:

IgniteCheckedException

stopStore

public void stopStore(int grpId,
 boolean freePages)
               throws IgniteCheckedException

Description copied from interface: PageMemory

Stops the store with the specified ID.

Specified by:

stopStore in interface PageMemory

Throws:

IgniteCheckedException

totalPages

public long totalPages()

Description copied from interface: PageMemory

Total pages can be placed to memory.

Specified by:

totalPages in interface PageMemory

allocatePage

public int allocatePage(int grpId,
 int tag)
                 throws IgniteCheckedException

Description copied from interface: PageMemory

Allocates a page from the space for the given partition ID and the given flags.

Specified by:

allocatePage in interface PageMemory

tag - Tag.

Returns:

page ID within the store.

Throws:

IgniteCheckedException - If failed.

metaPageId

public int metaPageId(int grpId)

Description copied from interface: PageMemory

Gets or allocates metadata page for specified grpId.

Specified by:

metaPageId in interface PageMemory

Parameters:

grpId - Group ID.

Returns:

Meta page ID for the store.

acquirePage

public long acquirePage(int grpId,
 int pageId,
 int tag)
                 throws IgniteCheckedException

Description copied from interface: PageMemory

Gets the page absolute pointer associated with the given page ID. Each page obtained with this method must be released by calling #releasePage(int, long, long).

An invocation of this method behaves exactly like the invocation acquirePage(grpId, pageId, false).

Specified by:

acquirePage in interface PageMemory

Parameters:

grpId - Group ID.

pageId - Page ID.

tag - Tag.

Returns:

Page pointer.

Throws:

IgniteCheckedException - If failed.

acquirePage

public long acquirePage(int grpId,
 int pageId,
 int tag,
 boolean restore)
                 throws IgniteCheckedException

Description copied from interface: PageMemory

Gets the page absolute pointer associated with the given page ID. Each page obtained with this method must be released by calling #releasePage(int, long, long).

Specified by:

acquirePage in interface PageMemory

Parameters:

grpId - Group ID.

pageId - Page ID.

tag - Tag.

restore - Whether the page is acquired for restoration.

Returns:

Page pointer.

Throws:

IgniteCheckedException - If failed.

releasePage

public void releasePage(int grpId,
 int pageId,
 long page)

Specified by:

releasePage in interface PageMemory

Parameters:

grpId - Group ID.

pageId - Page ID to release.

page - Page pointer.

readLock

public long readLock(int grpId,
 int pageId,
 long absPtr,
 int tag,
 boolean touch)

Specified by:

readLock in interface PageMemory

pageId - Page ID.

absPtr - Absolute pointer to read lock.

tag - Tag.

touch - Update page timestamp.

Returns:

Pointer to the page read buffer.

readUnlock

public void readUnlock(int grpId,
 int pageId,
 long page)

Description copied from interface: PageMemory

Releases locked page.

Specified by:

readUnlock in interface PageMemory

Parameters:

grpId - Cache group ID.

pageId - Page ID.

page - Page pointer.

writeLock

public long writeLock(int grpId,
 int pageId,
 long page,
 int tag)

Specified by:

writeLock in interface PageMemory

Parameters:

grpId - Group ID.

pageId - Page ID.

page - Absolute pointer to read lock.

tag - Tag.

Returns:

Pointer to the page read buffer.

tryWriteLock

public long tryWriteLock(int grpId,
 int pageId,
 long page,
 int tag)

Specified by:

tryWriteLock in interface PageMemory

Parameters:

grpId - Group ID.

pageId - Page ID.

page - Absolute pointer to read lock.

tag - Tag.

Returns:

Pointer to the page read buffer.

writeUnlock

public void writeUnlock(int grpId,
 int pageId,
 long page,
 boolean modified,
 int tag)

Specified by:

writeUnlock in interface PageMemory

Parameters:

grpId - Group ID.

pageId - Page ID.

page - Absolute pointer to read lock.

modified - Flag indicating whether the page was modified.

tag - Tag.

isDirty

public boolean isDirty(int grpId,
 int pageId,
 long page)

Specified by:

isDirty in interface PageMemory

Parameters:

grpId - Cache group ID.

pageId - Page ID.

page - Page pointer.

Returns:

true if the page is dirty.

beginCheckpoint

public void beginCheckpoint()
                     throws IgniteException

Description copied from interface: PageMemory

Begins a checkpoint.

Specified by:

beginCheckpoint in interface PageMemory

Throws:

IgniteException

finishCheckpoint

public void finishCheckpoint()

Description copied from interface: PageMemory

Finishes a checkpoint.

Specified by:

finishCheckpoint in interface PageMemory

runCheckpoint

public void runCheckpoint()
                   throws IgniteCheckedException

Description copied from interface: PageMemory

Runs a checkpoint.

Specified by:

runCheckpoint in interface PageMemory

Throws:

IgniteCheckedException

safeToUpdate

public boolean safeToUpdate()

Description copied from interface: PageMemory

Heuristic method which allows a thread to check if it safe to start memory struture modifications in regard with checkpointing. May return false-negative result during or after partition eviction.

Specified by:

safeToUpdate in interface PageMemory

Returns:

False if there are too many dirty pages and a thread should wait for a checkpoint to begin.

reduceMemoryFootprint

public void reduceMemoryFootprint()
                           throws IgniteCheckedException

Description copied from interface: PageMemory

Reduces memory footprint.

Specified by:

reduceMemoryFootprint in interface PageMemory

Throws:

IgniteCheckedException

metrics

public DataRegionMetrics metrics()

Returns:

Data region metrics.

dirtyPages

public Collection<Long> dirtyPages()

Gets a collection of all pages currently marked as dirty. Will create a collection copy.

Returns:

Collection of all page IDs marked as dirty.