org.h2.index

Class MultiVersionIndex

java.lang.Object

org.h2.index.MultiVersionIndex

All Implemented Interfaces:

DbObject, Index, SchemaObject

public class MultiVersionIndex
extends java.lang.Object
implements Index

A multi-version index is a combination of a regular index, and a in-memory tree index that contains uncommitted changes. Uncommitted changes can include new rows, and deleted rows.

Field Summary

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
MultiVersionIndex(Index base, RegularTable table)

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.
boolean	canScan() Can this index iterate over all rows?
void	checkRename() Check if renaming is allowed.
void	close(Session session) Close this index.
void	commit(int operation, Row row) Commit the operation for a row.
int	compareRows(SearchRow rowData, SearchRow compare) Compare two rows.
IndexLookupBatch	createLookupBatch(TableFilter[] filters, int filter) Creates new lookup batch.
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	find(TableFilter filter, 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.
Index	getBaseIndex()
java.util.ArrayList<DbObject>	getChildren() Get the list of dependent children (for tables, this includes indexes and so on).
int	getColumnIndex(Column col) Get the index of a column in the list of index columns
Column[]	getColumns() Get the indexed columns.
java.lang.String	getComment() Get the current comment of this object.
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.
java.lang.String	getCreateSQL() Construct the original CREATE ...
java.lang.String	getCreateSQLForCopy(Table forTable, java.lang.String quotedName) Build a SQL statement to re-create the object, or to create a copy of the object with a different name or referencing a different table
Database	getDatabase() Get the database.
long	getDiskSpaceUsed() Get the used disk space for this index.
java.lang.String	getDropSQL() Construct a DROP ...
int	getId() Get the unique object id.
IndexColumn[]	getIndexColumns() Get the indexed columns as index columns (with ordering information).
IndexType	getIndexType() Get the index type.
java.lang.String	getName() Get the name.
java.lang.String	getPlanSQL() Get the message to show in a EXPLAIN statement.
Row	getRow(Session session, long key) Get the row with the given key.
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.
Schema	getSchema() Get the schema in which this object is defined
java.lang.String	getSQL() Get the SQL name of this object (may be quoted).
Table	getTable() Get the table on which this index is based.
int	getType() Get the object type.
boolean	isFindUsingFullTableScan() Returns true if find() implementation performs scan over all index, false if find() performs the fast lookup.
boolean	isFirstColumn(Column column) Check if the given column is the first for this index
boolean	isHidden() Check whether this is a hidden object that doesn't appear in the meta data and in the script, and is not dropped on DROP ALL OBJECTS.
boolean	isRowIdIndex() Does this index support lookup by row id?
boolean	isTemporary() Check if this object is temporary (for example, a temporary table).
boolean	isUncommittedFromOtherSession(Session session, Row row) Check if there is an uncommitted row with the given key within a different session.
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	removeChildrenAndResources(Session session) Delete all dependent children objects and resources of this object.
void	rename(java.lang.String newName) Rename the object.
void	setComment(java.lang.String comment) Change the comment of this object.
void	setSortedInsertMode(boolean sortedInsertMode) Enable or disable the 'sorted insert' optimizations (rows are inserted in ascending or descending order) if applicable for this index implementation.
void	setTemporary(boolean temporary) Tell this object that it is temporary or not.
void	truncate(Session session) Remove all rows from the index.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiVersionIndex

public MultiVersionIndex(Index base,
                         RegularTable table)

Method Detail

add

public void add(Session session,
                Row row)

Description copied from interface: Index

Add a row to the index.

Specified by:

add in interface Index

Parameters:

session - the session to use

row - the row to add

close

public void close(Session session)

Description copied from interface: Index

Close this index.

Specified by:

close in interface Index

Parameters:

session - the session used to write data

isFindUsingFullTableScan

public boolean isFindUsingFullTableScan()

Description copied from interface: Index

Returns true if find() implementation performs scan over all index, false if find() performs the fast lookup.

Specified by:

isFindUsingFullTableScan in interface Index

Returns:

true if find() implementation performs scan over all index, false if find() performs the fast lookup

find

public Cursor find(TableFilter filter,
                   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.

Specified by:

find in interface Index

Parameters:

filter - the table filter (which possibly knows about additional conditions)

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

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.

Specified by:

find in interface Index

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

findNext

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

Description copied from interface: Index

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

Specified by:

findNext in interface Index

Parameters:

session - the session

first - the lower limit (excluding)

last - the last row, or null for no limit

Returns:

the cursor

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

Returns:

true if it can

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.

Specified by:

canGetFirstOrLast in interface Index

Returns:

true if it can

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.

Specified by:

findFirstOrLast in interface Index

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.

Specified by:

getCost in interface Index

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.

Specified by:

needRebuild in interface Index

Returns:

true if a rebuild is required.

isUncommittedFromOtherSession

public boolean isUncommittedFromOtherSession(Session session,
                                             Row row)

Check if there is an uncommitted row with the given key within a different session.

Parameters:

session - the original session

row - the row (only the key is checked)

Returns:

true if there is an uncommitted row

remove

public void remove(Session session,
                   Row row)

Description copied from interface: Index

Remove a row from the index.

Specified by:

remove in interface Index

Parameters:

session - the session

row - the row

remove

public void remove(Session session)

Description copied from interface: Index

Remove the index.

Specified by:

remove in interface Index

Parameters:

session - the session

truncate

public void truncate(Session session)

Description copied from interface: Index

Remove all rows from the index.

Specified by:

truncate in interface Index

Parameters:

session - the session

commit

public void commit(int operation,
                   Row row)

Description copied from interface: Index

Commit the operation for a row. This is only important for multi-version indexes. The method is only called if multi-version is enabled.

Specified by:

commit in interface Index

Parameters:

operation - the operation type

row - the row

compareRows

public int compareRows(SearchRow rowData,
                       SearchRow compare)

Description copied from interface: Index

Compare two rows.

Specified by:

compareRows in interface Index

Parameters:

rowData - the first row

compare - the second row

Returns:

0 if both rows are equal, -1 if the first row is smaller, otherwise 1

getColumnIndex

public int getColumnIndex(Column col)

Description copied from interface: Index

Get the index of a column in the list of index columns

Specified by:

getColumnIndex in interface Index

Parameters:

col - the column

Returns:

the index (0 meaning first column)

isFirstColumn

public boolean isFirstColumn(Column column)

Description copied from interface: Index

Check if the given column is the first for this index

Specified by:

isFirstColumn in interface Index

Parameters:

column - the column

Returns:

true if the given columns is the first

getColumns

public Column[] getColumns()

Description copied from interface: Index

Get the indexed columns.

Specified by:

getColumns in interface Index

Returns:

the columns

getIndexColumns

public IndexColumn[] getIndexColumns()

Description copied from interface: Index

Get the indexed columns as index columns (with ordering information).

Specified by:

getIndexColumns in interface Index

Returns:

the index columns

getCreateSQL

public java.lang.String getCreateSQL()

Description copied from interface: DbObject

Construct the original CREATE ... SQL statement for this object.

Specified by:

getCreateSQL in interface DbObject

Returns:

the SQL statement

getCreateSQLForCopy

public java.lang.String getCreateSQLForCopy(Table forTable,
                                            java.lang.String quotedName)

Description copied from interface: DbObject

Build a SQL statement to re-create the object, or to create a copy of the object with a different name or referencing a different table

Specified by:

getCreateSQLForCopy in interface DbObject

Parameters:

forTable - the new table

quotedName - the quoted name

Returns:

the SQL statement

getDropSQL

public java.lang.String getDropSQL()

Description copied from interface: DbObject

Construct a DROP ... SQL statement for this object.

Specified by:

getDropSQL in interface DbObject

Returns:

the SQL statement

getIndexType

public IndexType getIndexType()

Description copied from interface: Index

Get the index type.

Specified by:

getIndexType in interface Index

Returns:

the index type

getPlanSQL

public java.lang.String getPlanSQL()

Description copied from interface: Index

Get the message to show in a EXPLAIN statement.

Specified by:

getPlanSQL in interface Index

Returns:

the plan

getRowCount

public long getRowCount(Session session)

Description copied from interface: Index

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

Specified by:

getRowCount in interface Index

Parameters:

session - the session

Returns:

the row count

getTable

public Table getTable()

Description copied from interface: Index

Get the table on which this index is based.

Specified by:

getTable in interface Index

Returns:

the table

getType

public int getType()

Description copied from interface: DbObject

Get the object type.

Specified by:

getType in interface DbObject

Returns:

the object type

removeChildrenAndResources

public void removeChildrenAndResources(Session session)

Description copied from interface: DbObject

Delete all dependent children objects and resources of this object.

Specified by:

removeChildrenAndResources in interface DbObject

Parameters:

session - the session

getSQL

public java.lang.String getSQL()

Description copied from interface: DbObject

Get the SQL name of this object (may be quoted).

Specified by:

getSQL in interface DbObject

Returns:

the SQL name

getSchema

public Schema getSchema()

Description copied from interface: SchemaObject

Get the schema in which this object is defined

Specified by:

getSchema in interface SchemaObject

Returns:

the schema

checkRename

public void checkRename()

Description copied from interface: DbObject

Check if renaming is allowed. Does nothing when allowed.

Specified by:

checkRename in interface DbObject

getChildren

public java.util.ArrayList<DbObject> getChildren()

Description copied from interface: DbObject

Get the list of dependent children (for tables, this includes indexes and so on).

Specified by:

getChildren in interface DbObject

Returns:

the list of children

getComment

public java.lang.String getComment()

Description copied from interface: DbObject

Get the current comment of this object.

Specified by:

getComment in interface DbObject

Returns:

the comment, or null if not set

getDatabase

public Database getDatabase()

Description copied from interface: DbObject

Get the database.

Specified by:

getDatabase in interface DbObject

Returns:

the database

getId

public int getId()

Description copied from interface: DbObject

Get the unique object id.

Specified by:

getId in interface DbObject

Returns:

the object id

getName

public java.lang.String getName()

Description copied from interface: DbObject

Get the name.

Specified by:

getName in interface DbObject

Returns:

the name

isTemporary

public boolean isTemporary()

Description copied from interface: DbObject

Check if this object is temporary (for example, a temporary table).

Specified by:

isTemporary in interface DbObject

Returns:

true if is temporary

rename

public void rename(java.lang.String newName)

Description copied from interface: DbObject

Rename the object.

Specified by:

rename in interface DbObject

Parameters:

newName - the new name

setComment

public void setComment(java.lang.String comment)

Description copied from interface: DbObject

Change the comment of this object.

Specified by:

setComment in interface DbObject

Parameters:

comment - the new comment, or null for no comment

setTemporary

public void setTemporary(boolean temporary)

Description copied from interface: DbObject

Tell this object that it is temporary or not.

Specified by:

setTemporary in interface DbObject

Parameters:

temporary - the new value

getRowCountApproximation

public long getRowCountApproximation()

Description copied from interface: Index

Get the approximated row count for this table.

Specified by:

getRowCountApproximation in interface Index

Returns:

the approximated row count

getDiskSpaceUsed

public long getDiskSpaceUsed()

Description copied from interface: Index

Get the used disk space for this index.

Specified by:

getDiskSpaceUsed in interface Index

Returns:

the estimated number of bytes

getBaseIndex

public Index getBaseIndex()

getRow

public Row getRow(Session session,
                  long key)

Description copied from interface: Index

Get the row with the given key.

Specified by:

getRow in interface Index

Parameters:

session - the session

key - the unique key

Returns:

the row

isHidden

public boolean isHidden()

Description copied from interface: SchemaObject

Check whether this is a hidden object that doesn't appear in the meta data and in the script, and is not dropped on DROP ALL OBJECTS.

Specified by:

isHidden in interface SchemaObject

Returns:

true if it is hidden

isRowIdIndex

public boolean isRowIdIndex()

Description copied from interface: Index

Does this index support lookup by row id?

Specified by:

isRowIdIndex in interface Index

Returns:

true if it does

canScan

public boolean canScan()

Description copied from interface: Index

Can this index iterate over all rows?

Specified by:

canScan in interface Index

Returns:

true if it can

setSortedInsertMode

public void setSortedInsertMode(boolean sortedInsertMode)

Description copied from interface: Index

Enable or disable the 'sorted insert' optimizations (rows are inserted in ascending or descending order) if applicable for this index implementation.

Specified by:

setSortedInsertMode in interface Index

Parameters:

sortedInsertMode - the new value

createLookupBatch

public IndexLookupBatch createLookupBatch(TableFilter[] filters,
                                          int filter)

Description copied from interface: Index

Creates new lookup batch. Note that returned IndexLookupBatch instance can be used multiple times.

Specified by:

createLookupBatch in interface Index

Parameters:

filters - the table filters

filter - the filter index (0, 1,...)

Returns:

created batch or null if batched lookup is not supported by this index.