Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.impl.store.access.btree.BranchControlRow

Modifier and Type	Field and Description
pack-priv transient SQLLongint	child_pageno_buf Only allocate one child_pageno_buf to read the page pointer field into, then cache to "empty" object for reuse by the page itself.
private static final int	CR_COLID_LAST Hides org.apache.derby.impl.store.access.btree.ControlRow.CR_COLID_LAST.
private static final int	CR_LEFTCHILD
protected static final FormatableBitSet	CR_LEFTCHILD_BITMAP bit sets used to fetch single columns at a time.
private static final int	CR_NCOLUMNS Hides org.apache.derby.impl.store.access.btree.ControlRow.CR_NCOLUMNS.
protected SQLLongint	left_child_page

Access	Constructor and Description
public	BranchControlRow() No arg constructor.
public	BranchControlRow(OpenBTree open_btree, Page page, int level, ControlRow parent, boolean isRoot, long left_child)

Method Summary

Modifier and Type	Method and Description
private static BranchControlRow	allocate(OpenBTree open_btree, ControlRow leftchild, int level, ControlRow parent) Allocate a new leaf page to the conglomerate.
private void	checkChildOrderAgainstRowOrder(OpenBTree btree)
private int	checkChildren(OpenBTree btree)
public int	checkConsistency(OpenBTree The open btree to associate latches/locks with. btree, ControlRow The parent page of this page, "null" if this page is root or if not maintaining parent links. parent, boolean Should the consistency check go to other pages (this option breaks the latch protocol). check_other_pages) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency. Perform consistency checks for a branch page.</menu>
protected final void	controlRowInit() Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.controlRowInit. Perform page specific initialization.
private void	fixChildrensParents(OpenBTree btree, ControlRow leftchild) A branch page that has just been allocated as part of a split has index rows and a left child pointer that were copied from another page.
protected ControlRow	getChildPageAtSlot(OpenBTree open_btree, int slot)
private long	getChildPageIdAtSlot(OpenBTree btree, int slot)
public ControlRow	Returns: The page which is the leftmost child of this page. getLeftChild(OpenBTree The open btree to associate latches/locks with. open_btree) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getLeftChild. Return the left child pointer for the page.
pack-priv long	getLeftChildPageno() Return the left child page number for the page.
protected final int	Returns: The total number of columns in the control row. getNumberOfControlRowColumns() Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getNumberOfControlRowColumns. Get the number of columns in the control row.
protected ControlRow	Returns: The page which is the rightmost child of this page. getRightChild(OpenBTree The open btree to associate latches/locks with. open_btree) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getRightChild. Return the right child pointer for the page.
public DataValueDescriptor[]	Returns: Newly allocated template. getRowTemplate(OpenBTree open_btree) Overrides org.apache.derby.impl.store.access.btree.ControlRow.getRowTemplate. Return a new template for reading a data row from the current page.
public int	getTypeFormatId() Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId. Return my format identifier.
private static void	growRoot(OpenBTree open_btree, DataValueDescriptor[] template, BranchControlRow root) Add a level to the tree by moving the current branch-root page up one level and adding a new page as it's left child.
public boolean	Returns: true if the current page is the leftmost leaf of the tree, else return false. isLeftmostLeaf() Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.isLeftmostLeaf. Is the current page the leftmost leaf of tree?
public boolean	Returns: true if the current page is the rightmost leaf of the tree, else return false. isRightmostLeaf() Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.isRightmostLeaf. Is the current page the rightmost leaf of tree?
public void	printTree(OpenBTree the open btree to print. btree) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.printTree. Recursively print the tree starting at current node in tree.
public static long	restartSplitFor(OpenBTree open_btree, DataValueDescriptor[] template, BranchControlRow parent, ControlRow child, DataValueDescriptor[] newbranchrow, DataValueDescriptor[] splitrow, int flag)
public ControlRow	search(SearchParameters sp) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.search. Perform a recursive search, ultimately returning the latched leaf page and row slot after which the given key belongs.
protected ControlRow	Returns: The leftmost leaf page. searchLeft(OpenBTree The open btree to associate latches/locks with. btree) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.searchLeft. Search and return the left most leaf page.
protected ControlRow	Returns: The rightmost leaf page. searchRight(OpenBTree The open btree to associate latches/locks with. btree) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.searchRight. Search and return the right most leaf page.
protected void	setLeftChild(ControlRow leftchild)
protected void	setLeftChildPageno(long leftchild_pageno)
protected boolean	shrinkFor(OpenBTree open_btree, DataValueDescriptor[] shrink_key) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.shrinkFor. Perform a recursive shrink operation for the key.
protected long	Returns: page number of the newly allocated leaf page created by split. splitFor(OpenBTree The open btree to associate latches with. open_btree, DataValueDescriptor[] A scratch area to use while searching for split pass. template, BranchControlRow The parent page of the current page in the split pass. starts at null for root. parent, DataValueDescriptor[] The key to make room for during the split pass. splitrow, int A flag used to direct where point of split should be chosen. flag) Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.splitFor. Perform a top down split pass making room for the the key in "row".
public String	toString() Overrides org.apache.derby.impl.store.access.btree.ControlRow.toString. The standard toString.

child_pageno_buf	back to summary
pack-priv transient SQLLongint child_pageno_buf Only allocate one child_pageno_buf to read the page pointer field into, then cache to "empty" object for reuse by the page itself.

CR_COLID_LAST	back to summary
private static final int CR_COLID_LAST Hides org.apache.derby.impl.store.access.btree.ControlRow.CR_COLID_LAST.

CR_LEFTCHILD	back to summary
private static final int CR_LEFTCHILD

CR_LEFTCHILD_BITMAP	back to summary
protected static final FormatableBitSet CR_LEFTCHILD_BITMAP bit sets used to fetch single columns at a time.

CR_NCOLUMNS	back to summary
private static final int CR_NCOLUMNS Hides org.apache.derby.impl.store.access.btree.ControlRow.CR_NCOLUMNS.

left_child_page	back to summary
protected SQLLongint left_child_page

BranchControlRow	back to summary
public BranchControlRow() No arg constructor. Public no arg constructor is for the monitor to call for format id implementation, it should not be called for any other reason.

BranchControlRow	back to summary
public BranchControlRow(OpenBTree open_btree, Page page, int level, ControlRow parent, boolean isRoot, long left_child) throws StandardException

Method Detail

allocate	back to summary
private static BranchControlRow allocate(OpenBTree open_btree, ControlRow leftchild, int level, ControlRow parent) throws StandardException Allocate a new leaf page to the conglomerate. Exceptions StandardException: Standard exception policy.

allocate

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private static BranchControlRow allocate(OpenBTree open_btree, ControlRow leftchild, int level, ControlRow parent) throws StandardException

Allocate a new leaf page to the conglomerate.

Exceptions

StandardException:: Standard exception policy.

checkChildOrderAgainstRowOrder	back to summary
private void checkChildOrderAgainstRowOrder(OpenBTree btree) throws StandardException

checkChildren	back to summary
private int checkChildren(OpenBTree btree) throws StandardException

checkConsistency	back to summary
public int checkConsistency(OpenBTree btree, ControlRow parent, boolean check_other_pages) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency. Perform consistency checks for a branch page. The checks specific to a branch page are: The rows on the page are indeed branch rows, and they all have the correct number of fields (which is the b-tree's key fields plus one for the child page number. The child pages pointed to by the left child pointer and the index rows are linked together in the same order that they appear on the page. The child pages themselves are all consistent. This method also performs the consistency checks that are common to both leaf and branch pages (see ControlRow.checkGeneric). Parameters btree:OpenBTree Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency. The open btree to associate latches/locks with. parent:ControlRow Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency. The parent page of this page, "null" if this page is root or if not maintaining parent links. check_other_pages:boolean Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency. Should the consistency check go to other pages (this option breaks the latch protocol). Returns:int Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency. The identifier to be used to open the conglomerate later. Exceptions StandardException: Standard exception policy.

checkConsistency

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public int checkConsistency(OpenBTree btree, ControlRow parent, boolean check_other_pages) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency.

Perform consistency checks for a branch page. The checks specific to a branch page are:

The rows on the page are indeed branch rows, and they all have the correct number of fields (which is the b-tree's key fields plus one for the child page number.

The child pages pointed to by the left child pointer and the index rows are linked together in the same order that they appear on the page.

The child pages themselves are all consistent.

This method also performs the consistency checks that are common to both leaf and branch pages (see ControlRow.checkGeneric).

Parameters

btree:OpenBTree

Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency.

The open btree to associate latches/locks with.

parent:ControlRow

Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency.

The parent page of this page, "null" if this page is root or if not maintaining parent links.

check_other_pages:boolean

Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency.

Should the consistency check go to other pages (this option breaks the latch protocol).

Returns:int

Doc from org.apache.derby.impl.store.access.btree.ControlRow.checkConsistency.

The identifier to be used to open the conglomerate later.

Exceptions

StandardException:: Standard exception policy.

controlRowInit	back to summary
protected final void controlRowInit() Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.controlRowInit. Perform page specific initialization.

controlRowInit

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protected final void controlRowInit()

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.controlRowInit.

Perform page specific initialization.

fixChildrensParents	back to summary
private void fixChildrensParents(OpenBTree btree, ControlRow leftchild) throws StandardException A branch page that has just been allocated as part of a split has index rows and a left child pointer that were copied from another page. The parent link on the corresponding pages will still point to the original page. This method fixes their parent pointers so that they point to the curren page like they're supposed to. Note that maintaining the parent link is kind of a pain, and will slow down applications. It's only needed for consistency checks, so we may want to have implementations that don't bother to maintain it. This

fixChildrensParents

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private void fixChildrensParents(OpenBTree btree, ControlRow leftchild) throws StandardException

A branch page that has just been allocated as part of a split has index rows and a left child pointer that were copied from another page. The parent link on the corresponding pages will still point to the original page. This method fixes their parent pointers so that they point to the curren page like they're supposed to.

Note that maintaining the parent link is kind of a pain, and will slow down applications. It's only needed for consistency checks, so we may want to have implementations that don't bother to maintain it.

This

getChildPageAtSlot	back to summary
protected ControlRow getChildPageAtSlot(OpenBTree open_btree, int slot) throws StandardException

getChildPageIdAtSlot	back to summary
private long getChildPageIdAtSlot(OpenBTree btree, int slot) throws StandardException

getLeftChild	back to summary
public ControlRow getLeftChild(OpenBTree open_btree) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getLeftChild. Return the left child pointer for the page. Leaf pages don't have children, so they override this and return null. Parameters open_btree:OpenBTree The open btree to associate latches/locks with. Returns:ControlRow The page which is the leftmost child of this page. Exceptions StandardException: Standard exception policy.

getLeftChild

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public ControlRow getLeftChild(OpenBTree open_btree) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getLeftChild.

Return the left child pointer for the page.

Leaf pages don't have children, so they override this and return null.

Parameters

open_btree:OpenBTree: The open btree to associate latches/locks with.

Returns:ControlRow

The page which is the leftmost child of this page.

Exceptions

StandardException:: Standard exception policy.

getLeftChildPageno	back to summary
pack-priv long getLeftChildPageno() throws StandardException Return the left child page number for the page. Leaf pages don't have left children, so they override this and return null.

getNumberOfControlRowColumns	back to summary
protected final int getNumberOfControlRowColumns() Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getNumberOfControlRowColumns. Get the number of columns in the control row. Control rows all share the first columns as defined by this class and then add columns to the end of the control row. For instance a branch control row add a child page pointer field. Returns:int The total number of columns in the control row.

getNumberOfControlRowColumns

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protected final int getNumberOfControlRowColumns()

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getNumberOfControlRowColumns.

Get the number of columns in the control row.

Control rows all share the first columns as defined by this class and then add columns to the end of the control row. For instance a branch control row add a child page pointer field.

Returns:int: The total number of columns in the control row.

getRightChild	back to summary
protected ControlRow getRightChild(OpenBTree open_btree) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getRightChild. Return the right child pointer for the page. Leaf pages don't have children, so they override this and return null. Parameters open_btree:OpenBTree The open btree to associate latches/locks with. Returns:ControlRow The page which is the rightmost child of this page. Exceptions StandardException: Standard exception policy.

getRightChild

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protected ControlRow getRightChild(OpenBTree open_btree) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.getRightChild.

Return the right child pointer for the page.

Leaf pages don't have children, so they override this and return null.

Parameters

open_btree:OpenBTree: The open btree to associate latches/locks with.

Returns:ControlRow

The page which is the rightmost child of this page.

Exceptions

StandardException:: Standard exception policy.

getRowTemplate	back to summary
public DataValueDescriptor[] getRowTemplate(OpenBTree open_btree) throws StandardException Overrides org.apache.derby.impl.store.access.btree.ControlRow.getRowTemplate. Return a new template for reading a data row from the current page. Default implementation for rows which are the same as the conglomerates template, sub-classes can alter if underlying template is different (for instance branch rows add an extra field at the end). Returns:DataValueDescriptor[] Newly allocated template. Exceptions StandardException: Standard exception policy.

getRowTemplate

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public DataValueDescriptor[] getRowTemplate(OpenBTree open_btree) throws StandardException

Overrides org.apache.derby.impl.store.access.btree.ControlRow.getRowTemplate.

Return a new template for reading a data row from the current page.

Default implementation for rows which are the same as the conglomerates template, sub-classes can alter if underlying template is different (for instance branch rows add an extra field at the end).

Returns:DataValueDescriptor[]

Newly allocated template.

Exceptions

StandardException:: Standard exception policy.

getTypeFormatId back to summary

getTypeFormatId	back to summary
public int getTypeFormatId() Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId. Return my format identifier. Returns:int Doc from org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId. The identifier. (A UUID stuffed in an array of 16 bytes). See Also `org.apache.derby.iapi.services.io.TypedFormat#getTypeFormatId`

public int getTypeFormatId()

Implements org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId.

Return my format identifier.

Returns:int

Doc from org.apache.derby.iapi.services.io.TypedFormat.getTypeFormatId.

The identifier. (A UUID stuffed in an array of 16 bytes).

growRoot	back to summary
private static void growRoot(OpenBTree open_btree, DataValueDescriptor[] template, BranchControlRow root) throws StandardException Add a level to the tree by moving the current branch-root page up one level and adding a new page as it's left child. On exit the current root page remains the root of the tree. On entry, the current branch root page is expected to be latched. On exit, all latches will have been released. Latch order: o ROOT: on entry current root is latched. No other latches should be held. o ROOT_OLDCHILD: Get and Latch root's left child page. o ROOT_NEWCHILD: Allocate a new branch page with latch. o Conditionally fix up the parent links on the pages pointed at by the newly allocated page. Loop through slots on ROOT_NEWCHILD, from left to right getting and releasing latches. Note that fixChildrensParents() must not latch the leftchild as ROOT_OLDCHILD is already latched. Resolve (mikem) does order of release matter. o ROOT : released. o ROOT_NEWCHILD: released. o ROOT_OLDCHILD: released.

growRoot

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private static void growRoot(OpenBTree open_btree, DataValueDescriptor[] template, BranchControlRow root) throws StandardException

Add a level to the tree by moving the current branch-root page up one level and adding a new page as it's left child. On exit the current root page remains the root of the tree.

On entry, the current branch root page is expected to be latched. On exit, all latches will have been released.

Latch order: o ROOT: on entry current root is latched. No other latches should be held. o ROOT_OLDCHILD: Get and Latch root's left child page. o ROOT_NEWCHILD: Allocate a new branch page with latch. o Conditionally fix up the parent links on the pages pointed at by the newly allocated page. Loop through slots on ROOT_NEWCHILD, from left to right getting and releasing latches. Note that fixChildrensParents() must not latch the leftchild as ROOT_OLDCHILD is already latched.

Resolve

(mikem) does order of release matter. o ROOT : released. o ROOT_NEWCHILD: released. o ROOT_OLDCHILD: released.

isLeftmostLeaf	back to summary
public boolean isLeftmostLeaf() throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.isLeftmostLeaf. Is the current page the leftmost leaf of tree? Returns:boolean true if the current page is the leftmost leaf of the tree, else return false. Exceptions StandardException: Standard exception policy.

isLeftmostLeaf

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public boolean isLeftmostLeaf() throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.isLeftmostLeaf.

Is the current page the leftmost leaf of tree?

Returns:boolean

true if the current page is the leftmost leaf of the tree, else return false.

Exceptions

StandardException:: Standard exception policy.

isRightmostLeaf	back to summary
public boolean isRightmostLeaf() throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.isRightmostLeaf. Is the current page the rightmost leaf of tree? Returns:boolean true if the current page is the rightmost leaf of the tree, else return false. Exceptions StandardException: Standard exception policy.

isRightmostLeaf

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public boolean isRightmostLeaf() throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.isRightmostLeaf.

Is the current page the rightmost leaf of tree?

Returns:boolean

true if the current page is the rightmost leaf of the tree, else return false.

Exceptions

StandardException:: Standard exception policy.

printTree	back to summary
public void printTree(OpenBTree btree) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.printTree. Recursively print the tree starting at current node in tree. Parameters btree:OpenBTree the open btree to print. Exceptions StandardException: Standard exception policy.

printTree

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public void printTree(OpenBTree btree) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.printTree.

Recursively print the tree starting at current node in tree.

Parameters

btree:OpenBTree: the open btree to print.

Exceptions

StandardException:: Standard exception policy.

restartSplitFor	back to summary
public static long restartSplitFor(OpenBTree open_btree, DataValueDescriptor[] template, BranchControlRow parent, ControlRow child, DataValueDescriptor[] newbranchrow, DataValueDescriptor[] splitrow, int flag) throws StandardException

search	back to summary
public ControlRow search(SearchParameters sp) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.search. Perform a recursive search, ultimately returning the latched leaf page and row slot after which the given key belongs. The slot is returned in the result structure. If the key exists on the page, the result.exact will be true. Otherwise, result.exact will be false, and the row slot returned will be the one immediately preceding the position at which the key belongs. Exceptions StandardException: Standard exception policy.

back to summary

public ControlRow search(SearchParameters sp) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.search.

Perform a recursive search, ultimately returning the latched leaf page and row slot after which the given key belongs. The slot is returned in the result structure. If the key exists on the page, the result.exact will be true. Otherwise, result.exact will be false, and the row slot returned will be the one immediately preceding the position at which the key belongs.

Exceptions

StandardException:: Standard exception policy.

searchLeft	back to summary
protected ControlRow searchLeft(OpenBTree btree) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.searchLeft. Search and return the left most leaf page. Perform a recursive search, ultimately returning the leftmost leaf page which is the first leaf page in the leaf sibling chain. (This method might better be called getFirstLeafPage()). Parameters btree:OpenBTree The open btree to associate latches/locks with. Returns:ControlRow The leftmost leaf page. Exceptions StandardException: Standard exception policy.

searchLeft

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protected ControlRow searchLeft(OpenBTree btree) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.searchLeft.

Search and return the left most leaf page.

Perform a recursive search, ultimately returning the leftmost leaf page which is the first leaf page in the leaf sibling chain. (This method might better be called getFirstLeafPage()).

Parameters

btree:OpenBTree: The open btree to associate latches/locks with.

Returns:ControlRow

The leftmost leaf page.

Exceptions

StandardException:: Standard exception policy.

searchRight	back to summary
protected ControlRow searchRight(OpenBTree btree) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.searchRight. Search and return the right most leaf page. Perform a recursive search, ultimately returning the rightmost leaf page which is the last leaf page in the leaf sibling chain. (This method might better be called getLastLeafPage()). Parameters btree:OpenBTree The open btree to associate latches/locks with. Returns:ControlRow The rightmost leaf page. Exceptions StandardException: Standard exception policy.

searchRight

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protected ControlRow searchRight(OpenBTree btree) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.searchRight.

Search and return the right most leaf page.

Perform a recursive search, ultimately returning the rightmost leaf page which is the last leaf page in the leaf sibling chain. (This method might better be called getLastLeafPage()).

Parameters

btree:OpenBTree: The open btree to associate latches/locks with.

Returns:ControlRow

The rightmost leaf page.

Exceptions

StandardException:: Standard exception policy.

setLeftChild	back to summary
protected void setLeftChild(ControlRow leftchild) throws StandardException

setLeftChildPageno	back to summary
protected void setLeftChildPageno(long leftchild_pageno) throws StandardException

shrinkFor	back to summary
protected boolean shrinkFor(OpenBTree open_btree, DataValueDescriptor[] shrink_key) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.shrinkFor. Perform a recursive shrink operation for the key. If this method returns true, the caller should remove the corresponding entry for the page. This routine is not guaranteed to successfully shrink anything. The page lead to by the key might turn out not to be empty by the time shrink gets there, and shrinks will give up if there is a deadlock. The receiver page must be latched on entry and is returned latched. Exceptions StandardException: Standard exception policy.

shrinkFor

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protected boolean shrinkFor(OpenBTree open_btree, DataValueDescriptor[] shrink_key) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.shrinkFor.

Perform a recursive shrink operation for the key. If this method returns true, the caller should remove the corresponding entry for the page. This routine is not guaranteed to successfully shrink anything. The page lead to by the key might turn out not to be empty by the time shrink gets there, and shrinks will give up if there is a deadlock.

The receiver page must be latched on entry and is returned latched.

Exceptions

StandardException:: Standard exception policy.

splitFor	back to summary
protected long splitFor(OpenBTree open_btree, DataValueDescriptor[] template, BranchControlRow parent, DataValueDescriptor[] splitrow, int flag) throws StandardException Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.splitFor. Perform a top down split pass making room for the the key in "row". Perform a split such that a subsequent call to insert given the argument index row will likely find room for it. Since latches are released the client must code for the case where another user has grabbed the space made available by the split pass and be ready to do another split. Latches: o PARENT : is latched on entry (unless the split is the root then there is no parent. o THISBRANCH: the current page is latched on entry. o CHILD : latch the child page which will be pointed at by the left child pointer of the new page. RESOLVE (mikem) -see comments below o NEWPAGE : Allocate and latch new page. o CHILD : release. (RESOLVE) o fixparents: latch pages and reset their parent pointers. Conditionally fix up the parent links on the pages pointed at by the newly allocated page. First get latch and release on the left child page and then loop through slots on NEWPAGE, from left to right getting and releasing latches. Parameters open_btree:OpenBTree The open btree to associate latches with. template:DataValueDescriptor[] A scratch area to use while searching for split pass. parent:BranchControlRow The parent page of the current page in the split pass. starts at null for root. splitrow:DataValueDescriptor[] The key to make room for during the split pass. flag:int A flag used to direct where point of split should be chosen. Returns:long page number of the newly allocated leaf page created by split. Exceptions StandardException: Standard exception policy.

splitFor

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protected long splitFor(OpenBTree open_btree, DataValueDescriptor[] template, BranchControlRow parent, DataValueDescriptor[] splitrow, int flag) throws StandardException

Implements abstract org.apache.derby.impl.store.access.btree.ControlRow.splitFor.

Perform a top down split pass making room for the the key in "row".

Perform a split such that a subsequent call to insert given the argument index row will likely find room for it. Since latches are released the client must code for the case where another user has grabbed the space made available by the split pass and be ready to do another split.

Latches: o PARENT : is latched on entry (unless the split is the root then there is no parent. o THISBRANCH: the current page is latched on entry. o CHILD : latch the child page which will be pointed at by the left child pointer of the new page. RESOLVE (mikem) -see comments below o NEWPAGE : Allocate and latch new page. o CHILD : release. (RESOLVE) o fixparents: latch pages and reset their parent pointers. Conditionally fix up the parent links on the pages pointed at by the newly allocated page. First get latch and release on the left child page and then loop through slots on NEWPAGE, from left to right getting and releasing latches.

Parameters

open_btree:OpenBTree: The open btree to associate latches with.
template:DataValueDescriptor[]: A scratch area to use while searching for split pass.
parent:BranchControlRow: The parent page of the current page in the split pass. starts at null for root.
splitrow:DataValueDescriptor[]: The key to make room for during the split pass.
flag:int: A flag used to direct where point of split should be chosen.

Returns:long

page number of the newly allocated leaf page created by split.

Exceptions

StandardException:: Standard exception policy.

toString	back to summary
public String toString() Overrides org.apache.derby.impl.store.access.btree.ControlRow.toString. The standard toString. Returns:String Doc from java.lang.Object.toString. a string representation of the object

toString

back to summary

public String toString()

Overrides org.apache.derby.impl.store.access.btree.ControlRow.toString.

The standard toString.

Returns:String

Doc from java.lang.Object.toString.

a string representation of the object

public Class BranchControlRow

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail