org.h2.index

Class PageBtreeIndex

java.lang.Object

org.h2.engine.DbObjectBase

org.h2.schema.SchemaObjectBase

org.h2.index.BaseIndex

org.h2.index.PageIndex

org.h2.index.PageBtreeIndex

All Implemented Interfaces:

DbObject, Index, SchemaObject

public class PageBtreeIndex
extends PageIndex

This is the most common type of index, a b tree index. Only the data of the indexed columns are stored in the index.

Field Summary

Fields inherited from class org.h2.index.PageIndex

rootPageId

Fields inherited from class org.h2.index.BaseIndex

columnIds, columns, indexColumns, indexType, isMultiVersion, table

Fields inherited from class org.h2.engine.DbObjectBase

comment, database, trace

Fields inherited from interface org.h2.engine.DbObject

AGGREGATE, COMMENT, CONSTANT, CONSTRAINT, FUNCTION_ALIAS, INDEX, RIGHT, ROLE, SCHEMA, SEQUENCE, SETTING, SYNONYM, TABLE_OR_VIEW, TRIGGER, USER, USER_DATATYPE

Constructor Summary

Constructors

Constructor and Description
PageBtreeIndex(RegularTable table, int id, java.lang.String indexName, IndexColumn[] columns, IndexType indexType, boolean create, Session session)

Method Summary

Modifier and Type	Method and Description
void	add(Session session, Row row) Add a row to the index.
boolean	canFindNext() Check if the index can get the next higher value.
boolean	canGetFirstOrLast() Check if the index can directly look up the lowest or highest value of a column.
void	checkRename() Check if this object can be renamed.
void	close(Session session) Close this index.
Cursor	find(Session session, SearchRow first, SearchRow last) Find a row or a list of rows and create a cursor to iterate over the result.
Cursor	findFirstOrLast(Session session, boolean first) Find the first (or last) value of this index.
Cursor	findNext(Session session, SearchRow first, SearchRow last) Find a row or a list of rows that is larger and create a cursor to iterate over the result.
double	getCost(Session session, int[] masks, TableFilter[] filters, int filter, SortOrder sortOrder, java.util.HashSet<Column> allColumnsSet) Estimate the cost to search for rows given the search mask.
long	getDiskSpaceUsed() Get the used disk space for this index.
Row	getRow(Session session, long key) Get a row from the main index.
long	getRowCount(Session session) Get the row count of this table, for the given session.
long	getRowCountApproximation() Get the approximated row count for this table.
boolean	needRebuild() Check if the index needs to be rebuilt.
void	remove(Session session) Remove the index.
void	remove(Session session, Row row) Remove a row from the index.
void	truncate(Session session) Remove all rows from the index.
void	writeRowCount() Write back the row count if it has changed.

Methods inherited from class org.h2.index.PageIndex

getRootPageId, setSortedInsertMode

Methods inherited from class org.h2.index.BaseIndex

canScan, checkIndexColumnTypes, commit, compareRows, createLookupBatch, find, getColumnIndex, getColumns, getCostRangeIndex, getCreateSQL, getCreateSQLForCopy, getDropSQL, getDuplicateKeyException, getIndexColumns, getIndexType, getPlanSQL, getTable, getType, initBaseIndex, isFindUsingFullTableScan, isFirstColumn, isHidden, isRowIdIndex, mayHaveNullDuplicates, removeChildrenAndResources

Methods inherited from class org.h2.schema.SchemaObjectBase

getSchema, getSQL, initSchemaObjectBase

Methods inherited from class org.h2.engine.DbObjectBase

getChildren, getComment, getDatabase, getId, getModificationId, getName, initDbObjectBase, invalidate, isTemporary, isValid, rename, setComment, setModified, setObjectName, setTemporary, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.schema.SchemaObject

getSchema

Methods inherited from interface org.h2.engine.DbObject

getChildren, getComment, getDatabase, getId, getName, getSQL, isTemporary, rename, setComment, setTemporary

Constructor Detail

PageBtreeIndex

public PageBtreeIndex(RegularTable table,
                      int id,
                      java.lang.String indexName,
                      IndexColumn[] columns,
                      IndexType indexType,
                      boolean create,
                      Session session)

Method Detail

add

public void add(Session session,
                Row row)

Description copied from interface: Index

Add a row to the index.

Parameters:

session - the session to use

row - the row to add

canGetFirstOrLast

public boolean canGetFirstOrLast()

Description copied from interface: Index

Check if the index can directly look up the lowest or highest value of a column.

Returns:

true if it can

findNext

public Cursor findNext(Session session,
                       SearchRow first,
                       SearchRow last)

Description copied from class: BaseIndex

Find a row or a list of rows that is larger and create a cursor to iterate over the result. The base implementation doesn't support this feature.

Specified by:

findNext in interface Index

Overrides:

findNext in class BaseIndex

Parameters:

session - the session

first - the lower limit (excluding)

last - the last row, or null for no limit

Returns:

the cursor

find

public Cursor find(Session session,
                   SearchRow first,
                   SearchRow last)

Description copied from interface: Index

Find a row or a list of rows and create a cursor to iterate over the result.

Parameters:

session - the session

first - the first row, or null for no limit

last - the last row, or null for no limit

Returns:

the cursor to iterate over the results

findFirstOrLast

public Cursor findFirstOrLast(Session session,
                              boolean first)

Description copied from interface: Index

Find the first (or last) value of this index. The cursor returned is positioned on the correct row, or on null if no row has been found.

Parameters:

session - the session

first - true if the first (lowest for ascending indexes) or last value should be returned

Returns:

a cursor (never null)

getCost

public double getCost(Session session,
                      int[] masks,
                      TableFilter[] filters,
                      int filter,
                      SortOrder sortOrder,
                      java.util.HashSet<Column> allColumnsSet)

Description copied from interface: Index

Estimate the cost to search for rows given the search mask. There is one element per column in the search mask. For possible search masks, see IndexCondition.

Parameters:

session - the session

masks - per-column comparison bit masks, null means 'always false', see constants in IndexCondition

filters - all joined table filters

filter - the current table filter index

sortOrder - the sort order

allColumnsSet - the set of all columns

Returns:

the estimated cost

needRebuild

public boolean needRebuild()

Description copied from interface: Index

Check if the index needs to be rebuilt. This method is called after opening an index.

Returns:

true if a rebuild is required.

remove

public void remove(Session session,
                   Row row)

Description copied from interface: Index

Remove a row from the index.

Parameters:

session - the session

row - the row

remove

public void remove(Session session)

Description copied from interface: Index

Remove the index.

Parameters:

session - the session

truncate

public void truncate(Session session)

Description copied from interface: Index

Remove all rows from the index.

Parameters:

session - the session

checkRename

public void checkRename()

Description copied from class: DbObjectBase

Check if this object can be renamed. System objects may not be renamed.

Specified by:

checkRename in interface DbObject

Specified by:

checkRename in class DbObjectBase

getRow

public Row getRow(Session session,
                  long key)

Get a row from the main index.

Specified by:

getRow in interface Index

Overrides:

getRow in class BaseIndex

Parameters:

session - the session

key - the row key

Returns:

the row

getRowCountApproximation

public long getRowCountApproximation()

Description copied from interface: Index

Get the approximated row count for this table.

Returns:

the approximated row count

getDiskSpaceUsed

public long getDiskSpaceUsed()

Description copied from interface: Index

Get the used disk space for this index.

Returns:

the estimated number of bytes

getRowCount

public long getRowCount(Session session)

Description copied from interface: Index

Get the row count of this table, for the given session.

Parameters:

session - the session

Returns:

the row count

close

public void close(Session session)

Description copied from interface: Index

Close this index.

Parameters:

session - the session used to write data

canFindNext

public boolean canFindNext()

Description copied from interface: Index

Check if the index can get the next higher value.

Specified by:

canFindNext in interface Index

Overrides:

canFindNext in class BaseIndex

Returns:

true if it can

writeRowCount

public void writeRowCount()

Description copied from class: PageIndex

Write back the row count if it has changed.

Specified by:

writeRowCount in class PageIndex