public class BTreeRowPosition extends RowPosition
Modifier and Type | Field and Description |
---|---|
LeafControlRow |
current_leaf |
RowLocation |
current_lock_row_loc |
DataValueDescriptor[] |
current_lock_template |
DataValueDescriptor[] |
current_positionKey
Fields of the class
|
protected LeafControlRow |
next_leaf |
private BTreeScan |
parent
The scan that owns this position object.
|
private DataValueDescriptor[] |
positionKey_template
Cached template for saving this position by key.
|
private FetchDescriptor |
savedFetchDescriptor
Cached fetch descriptor that can be used to fetch the key columns that
are not already fetched by the scan.
|
(package private) long |
versionWhenSaved
The version number of the leaf page when this position was saved by
key.
|
current_page, current_pageno, current_rh, current_rh_qualified, current_slot
Constructor and Description |
---|
BTreeRowPosition(BTreeScan parent)
Constructors for This class:
|
Modifier and Type | Method and Description |
---|---|
(package private) FetchDescriptor |
getFetchDescriptorForSaveKey(int[] vcols,
int fullLength)
Get a fetch descriptor that can be used to fetch the missing columns
in a partial key.
|
(package private) DataValueDescriptor[] |
getKeyTemplate()
Get a template into which the position key can be copied.
|
void |
init()
Public Methods of This class:
|
void |
saveMeAndReleasePage()
Save this position by key and release the latch on the current leaf.
|
java.lang.String |
toString() |
void |
unlatch() |
positionAtNextSlot, positionAtPrevSlot
public DataValueDescriptor[] current_positionKey
public LeafControlRow current_leaf
protected LeafControlRow next_leaf
public DataValueDescriptor[] current_lock_template
public RowLocation current_lock_row_loc
private final BTreeScan parent
long versionWhenSaved
current_positionKey
is non-null. This value
is used to decide whether repositioning should be performed by using
the key, or if RowPosition.current_rh
could be used directly.private DataValueDescriptor[] positionKey_template
private FetchDescriptor savedFetchDescriptor
public BTreeRowPosition(BTreeScan parent)
public void init()
init
in class RowPosition
public final void unlatch()
unlatch
in class RowPosition
public void saveMeAndReleasePage() throws StandardException
StandardException
- if an error occurs while saving the positionBTreeScan.savePositionAndReleasePage()
DataValueDescriptor[] getKeyTemplate() throws StandardException
StandardException
- if an error occurs while allocating the
template arrayFetchDescriptor getFetchDescriptorForSaveKey(int[] vcols, int fullLength)
vcols
- an array which tells which columns the partial key contains
(valid columns have non-zero values in the array)fullLength
- the length of the full key to create a fetch
descriptor for (may be greater than vcols.length
)public final java.lang.String toString()
toString
in class RowPosition
Apache Derby V10.13 Internals - Copyright © 2004,2016 The Apache Software Foundation. All Rights Reserved.