org.h2.index

Class PageDataOverflow

java.lang.Object

org.h2.util.CacheObject

org.h2.store.Page

org.h2.index.PageDataOverflow

All Implemented Interfaces:

java.lang.Comparable<CacheObject>

public class PageDataOverflow
extends Page

Overflow data for a leaf page. Format:

• page type: byte (0)
• checksum: short (1-2)
• parent page id (0 for root): int (3-6)
• more data: next overflow page id: int (7-10)
• last remaining size: short (7-8)
• data (11-/9-)

Field Summary

Fields inherited from class org.h2.store.Page

changeCount, FLAG_LAST, TYPE_BTREE_LEAF, TYPE_BTREE_NODE, TYPE_DATA_LEAF, TYPE_DATA_NODE, TYPE_DATA_OVERFLOW, TYPE_EMPTY, TYPE_FREE_LIST, TYPE_STREAM_DATA, TYPE_STREAM_TRUNK

Fields inherited from class org.h2.util.CacheObject

cacheChained, cacheNext, cachePrevious

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canRemove() Check if the object can be removed from the cache.
int	getMemory() Get the estimated memory size.
boolean	isStream()
void	moveTo(Session session, int newPos) Copy the data to a new location, change the parent to point to the new location, and free up the current page.
static Page	read(PageStore store, Data data, int pageId) Read an overflow page.
java.lang.String	toString()
void	write() Write the page.

Methods inherited from class org.h2.store.Page

add, canMove, insert, insert, insert, remove, remove, remove

Methods inherited from class org.h2.util.CacheObject

compareTo, getPos, isChanged, setChanged, setPos

Methods inherited from class java.lang.Object

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

Method Detail

read

public static Page read(PageStore store,
        Data data,
        int pageId)

Read an overflow page.

Parameters:

store - the page store

data - the data

pageId - the page id

Returns:

the page

write

public void write()

Description copied from class: Page

Write the page.

Specified by:

write in class Page

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getMemory

public int getMemory()

Get the estimated memory size.

Specified by:

getMemory in class CacheObject

Returns:

number of double words (4 bytes)

moveTo

public void moveTo(Session session,
          int newPos)

Description copied from class: Page

Copy the data to a new location, change the parent to point to the new location, and free up the current page.

Specified by:

moveTo in class Page

Parameters:

session - the session

newPos - the new position

canRemove

public boolean canRemove()

Description copied from class: CacheObject

Check if the object can be removed from the cache. For example pinned objects can not be removed.

Specified by:

canRemove in class CacheObject

Returns:

true if it can be removed

isStream

public boolean isStream()

Overrides:

isStream in class CacheObject