org.h2.index

类 PageDataLeaf

java.lang.Object

org.h2.util.CacheObject

org.h2.store.Page

org.h2.index.PageDataLeaf

所有已实现的接口:

Comparable<CacheObject>

public class PageDataLeaf
extends Page

A leaf page that contains data of one or multiple rows. Format:

• page type: byte (0)
• checksum: short (1-2)
• parent page id (0 for root): int (3-6)
• table id: varInt
• column count: varInt
• entry count: short
• with overflow: the first overflow page id: int
• list of key / offset pairs (key: varLong, offset: shortInt)
• data

字段概要

字段

限定符和类型	字段和说明
protected Data	data The data page.
protected int	entryCount The number of entries.
protected PageDataIndex	index The index.
protected long[]	keys The row keys.
protected int	parentPageId The page number of the parent.
protected boolean	written Whether the data page is up-to-date.

从类继承的字段 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

从类继承的字段 org.h2.util.CacheObject

cacheChained, cacheNext, cachePrevious

方法概要

限定符和类型	方法和说明
boolean	canRemove() Check if the object can be removed from the cache.
int	getMemory() Get the estimated heap 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(PageDataIndex index, Data data, int pageId) Read a data leaf page.
protected void	remapChildren(int old) Update the parent id of all children.
String	toString()
void	write() Write the page.

从类继承的方法 org.h2.store.Page

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

从类继承的方法 org.h2.util.CacheObject

compareTo, getPos, isChanged, setChanged, setPos

从类继承的方法 java.lang.Object

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

字段详细资料

index

protected final PageDataIndex index

The index.

parentPageId

protected int parentPageId

The page number of the parent.

data

protected final Data data

The data page.

entryCount

protected int entryCount

The number of entries.

keys

protected long[] keys

The row keys.

written

protected boolean written

Whether the data page is up-to-date.

方法详细资料

read

public static Page read(PageDataIndex index,
                        Data data,
                        int pageId)

Read a data leaf page.

参数:

index - the index

data - the data

pageId - the page id

返回:

the page

remapChildren

protected void remapChildren(int old)

Update the parent id of all children.

参数:

old - the previous position

write

public void write()

从类复制的说明: Page

Write the page.

指定者:

write 在类中 Page

toString

public String toString()

覆盖:

toString 在类中 Object

moveTo

public void moveTo(Session session,
                   int newPos)

从类复制的说明: Page

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

指定者:

moveTo 在类中 Page

参数:

session - the session

newPos - the new position

isStream

public boolean isStream()

覆盖:

isStream 在类中 CacheObject

getMemory

public int getMemory()

Get the estimated heap memory size.

指定者:

getMemory 在类中 CacheObject

返回:

number of double words (4 bytes each)

canRemove

public boolean canRemove()

从类复制的说明: CacheObject

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

指定者:

canRemove 在类中 CacheObject

返回:

true if it can be removed