/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.mvstore.db;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.TreeSet;
import org.h2.api.ErrorCode;
import org.h2.engine.Database;
import org.h2.engine.Session;
import org.h2.index.BaseIndex;
import org.h2.index.Cursor;
import org.h2.index.IndexType;
import org.h2.message.DbException;
import org.h2.mvstore.MVMap;
import org.h2.mvstore.db.TransactionStore.Transaction;
import org.h2.mvstore.db.TransactionStore.TransactionMap;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.result.SortOrder;
import org.h2.table.Column;
import org.h2.table.IndexColumn;
import org.h2.table.TableFilter;
import org.h2.util.New;
import org.h2.value.CompareMode;
import org.h2.value.Value;
import org.h2.value.ValueArray;
import org.h2.value.ValueLong;
import org.h2.value.ValueNull;
/**
* A table stored in a MVStore.
*/
//索引数据也放在Map中，
//map的key由索引字段和MVPrimaryIndex的key组成，把它们合成一个ValueArray，MVPrimaryIndex的key放在ValueArray的最后，
//map的value总是ValueNull.INSTANCE
public class MVSecondaryIndex extends BaseIndex implements MVIndex {
/**
* The multi-value table.
*/
final MVTable mvTable;
private final int keyColumns;
private final String mapName;
private TransactionMap<Value, Value> dataMap;
public MVSecondaryIndex(Database db, MVTable table, int id, String indexName,
IndexColumn[] columns, IndexType indexType) {
this.mvTable = table;
initBaseIndex(table, id, indexName, columns, indexType);
if (!database.isStarting()) {
checkIndexColumnTypes(columns);
}
// always store the row key in the map key,
// even for unique indexes, as some of the index columns could be null
keyColumns = columns.length + 1;
mapName = "index." + getId();
int[] sortTypes = new int[keyColumns];
for (int i = 0; i < columns.length; i++) {
sortTypes[i] = columns[i].sortType;
}
sortTypes[keyColumns - 1] = SortOrder.ASCENDING;
ValueDataType keyType = new ValueDataType(
db.getCompareMode(), db, sortTypes);
ValueDataType valueType = new ValueDataType(null, null, null);
Transaction t = mvTable.getTransaction(null);
dataMap = t.openMap(mapName, keyType, valueType);
t.commit();
if (!keyType.equals(dataMap.getKeyType())) {
throw DbException.throwInternalError("Incompatible key type");
}
}
@Override
public void addRowsToBuffer(List<Row> rows, String bufferName) {
MVMap<Value, Value> map = openMap(bufferName);
for (Row row : rows) {
ValueArray key = convertToKey(row);
map.put(key, ValueNull.INSTANCE);
}
}
@Override
public void addBufferedRows(List<String> bufferNames) {
ArrayList<String> mapNames = New.arrayList(bufferNames);
final CompareMode compareMode = database.getCompareMode();
/**
* A source of values.
*/
class Source implements Comparable<Source> {
Value value;
Iterator<Value> next;
int sourceId;
@Override
public int compareTo(Source o) {
int comp = value.compareTo(o.value, compareMode);
if (comp == 0) {
comp = sourceId - o.sourceId;
}
return comp;
}
}
TreeSet<Source> sources = new TreeSet<Source>();
for (int i = 0; i < bufferNames.size(); i++) {
MVMap<Value, Value> map = openMap(bufferNames.get(i));
Iterator<Value> it = map.keyIterator(null);
if (it.hasNext()) {
Source s = new Source();
s.value = it.next();
s.next = it;
s.sourceId = i;
sources.add(s);
}
}
try {
while (true) {
Source s = sources.first();
Value v = s.value;
if (indexType.isUnique()) {
Value[] array = ((ValueArray) v).getList();
// don't change the original value
array = array.clone();
array[keyColumns - 1] = ValueLong.get(Long.MIN_VALUE);
ValueArray unique = ValueArray.get(array);
SearchRow row = convertToSearchRow((ValueArray) v);
checkUnique(row, dataMap, unique);
}
dataMap.putCommitted(v, ValueNull.INSTANCE);
Iterator<Value> it = s.next;
if (!it.hasNext()) {
sources.remove(s);
if (sources.size() == 0) {
break;
}
} else {
Value nextValue = it.next();
sources.remove(s);
s.value = nextValue;
sources.add(s);
}
}
} finally {
for (String tempMapName : mapNames) {
MVMap<Value, Value> map = openMap(tempMapName);
map.getStore().removeMap(map);
}
}
}
private MVMap<Value, Value> openMap(String mapName) {
int[] sortTypes = new int[keyColumns];
for (int i = 0; i < indexColumns.length; i++) {
sortTypes[i] = indexColumns[i].sortType;
}
sortTypes[keyColumns - 1] = SortOrder.ASCENDING;
ValueDataType keyType = new ValueDataType(
database.getCompareMode(), database, sortTypes);
ValueDataType valueType = new ValueDataType(null, null, null);
MVMap.Builder<Value, Value> builder =
new MVMap.Builder<Value, Value>().keyType(keyType).valueType(valueType);
MVMap<Value, Value> map = database.getMvStore().
getStore().openMap(mapName, builder);
if (!keyType.equals(map.getKeyType())) {
throw DbException.throwInternalError("Incompatible key type");
}
return map;
}
@Override
public void close(Session session) {
// ok
}
@Override
public void add(Session session, Row row) {
TransactionMap<Value, Value> map = getMap(session);
ValueArray array = convertToKey(row);
ValueArray unique = null;
if (indexType.isUnique()) { //为唯一索引增加记录的代价很高，前后都要检查map一次，是否考虑用HashMap?
// this will detect committed entries only
unique = convertToKey(row);
unique.getList()[keyColumns - 1] = ValueLong.get(Long.MIN_VALUE);
checkUnique(row, map, unique);
}
try {
map.put(array, ValueNull.INSTANCE);
} catch (IllegalStateException e) {
throw mvTable.convertException(e);
}
if (indexType.isUnique()) {
Iterator<Value> it = map.keyIterator(unique, true);
while (it.hasNext()) {
ValueArray k = (ValueArray) it.next();
SearchRow r2 = convertToSearchRow(k);
if (compareRows(row, r2) != 0) {
break;
}
if (containsNullAndAllowMultipleNull(r2)) {
// this is allowed
continue;
}
if (map.isSameTransaction(k)) {
continue;
}
if (map.get(k) != null) {
// committed
throw getDuplicateKeyException(k.toString());
}
throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, table.getName());
}
}
}
private void checkUnique(SearchRow row, TransactionMap<Value, Value> map, ValueArray unique) {
Iterator<Value> it = map.keyIterator(unique, true);
while (it.hasNext()) {
ValueArray k = (ValueArray) it.next();
SearchRow r2 = convertToSearchRow(k);
if (compareRows(row, r2) != 0) {
break;
}
if (map.get(k) != null) {
if (!containsNullAndAllowMultipleNull(r2)) {
throw getDuplicateKeyException(k.toString());
}
}
}
}
@Override
public void remove(Session session, Row row) {
ValueArray array = convertToKey(row);
TransactionMap<Value, Value> map = getMap(session);
try {
Value old = map.remove(array);
if (old == null) {
throw DbException.get(ErrorCode.ROW_NOT_FOUND_WHEN_DELETING_1,
getSQL() + ": " + row.getKey());
}
} catch (IllegalStateException e) {
throw mvTable.convertException(e);
}
}
@Override
public Cursor find(Session session, SearchRow first, SearchRow last) {
return find(session, first, false, last);
}
private Cursor find(Session session, SearchRow first, boolean bigger, SearchRow last) {
ValueArray min = convertToKey(first);
if (min != null) {
min.getList()[keyColumns - 1] = ValueLong.get(Long.MIN_VALUE);
}
TransactionMap<Value, Value> map = getMap(session);
if (bigger && min != null) {
// search for the next: first skip 1, then 2, 4, 8, until
// we have a higher key; then skip 4, 2,...
// (binary search), until 1
int offset = 1;
while (true) {
ValueArray v = (ValueArray) map.relativeKey(min, offset);
if (v != null) {
boolean foundHigher = false;
for (int i = 0; i < keyColumns - 1; i++) {
int idx = columnIds[i];
Value b = first.getValue(idx);
if (b == null) {
break;
}
Value a = v.getList()[i];
if (database.compare(a, b) > 0) {
foundHigher = true;
break;
}
}
if (!foundHigher) {
offset += offset;
min = v;
continue;
}
}
if (offset > 1) {
offset /= 2;
continue;
}
if (map.get(v) == null) {
min = (ValueArray) map.higherKey(min);
if (min == null) {
break;
}
continue;
}
min = v;
break;
}
if (min == null) {
return new MVStoreCursor(session,
Collections.<Value>emptyList().iterator(), null);
}
}
return new MVStoreCursor(session, map.keyIterator(min), last);
}
private ValueArray convertToKey(SearchRow r) {
if (r == null) {
return null;
}
Value[] array = new Value[keyColumns];
for (int i = 0; i < columns.length; i++) {
Column c = columns[i];
int idx = c.getColumnId();
Value v = r.getValue(idx);
if (v != null) {
array[i] = v.convertTo(c.getType());
}
}
array[keyColumns - 1] = ValueLong.get(r.getKey());
return ValueArray.get(array);
}
/**
* Convert array of values to a SearchRow.
*
* @param key the index key
* @return the row
*/
SearchRow convertToSearchRow(ValueArray key) {
Value[] array = key.getList();
SearchRow searchRow = mvTable.getTemplateRow();
searchRow.setKey((array[array.length - 1]).getLong());
Column[] cols = getColumns();
for (int i = 0; i < array.length - 1; i++) {
Column c = cols[i];
int idx = c.getColumnId();
Value v = array[i];
searchRow.setValue(idx, v);
}
return searchRow;
}
@Override
public MVTable getTable() {
return mvTable;
}
@Override
public double getCost(Session session, int[] masks,
TableFilter[] filters, int filter, SortOrder sortOrder,
HashSet<Column> allColumnsSet) {
try {
return 10 * getCostRangeIndex(masks, dataMap.sizeAsLongMax(),
filters, filter, sortOrder, false, allColumnsSet);
} catch (IllegalStateException e) {
throw DbException.get(ErrorCode.OBJECT_CLOSED, e);
}
}
@Override
public void remove(Session session) {
TransactionMap<Value, Value> map = getMap(session);
if (!map.isClosed()) {
Transaction t = mvTable.getTransaction(session);
t.removeMap(map);
}
}
@Override
public void truncate(Session session) {
TransactionMap<Value, Value> map = getMap(session);
map.clear();
}
@Override
public boolean canGetFirstOrLast() {
return true;
}
@Override
public Cursor findFirstOrLast(Session session, boolean first) {
TransactionMap<Value, Value> map = getMap(session);
Value key = first ? map.firstKey() : map.lastKey();
while (true) {
if (key == null) {
return new MVStoreCursor(session,
Collections.<Value>emptyList().iterator(), null);
}
if (((ValueArray) key).getList()[0] != ValueNull.INSTANCE) {
break;
}
key = first ? map.higherKey(key) : map.lowerKey(key);
}
ArrayList<Value> list = New.arrayList();
list.add(key);
MVStoreCursor cursor = new MVStoreCursor(session, list.iterator(), null);
cursor.next();
return cursor;
}
@Override
public boolean needRebuild() {
try {
return dataMap.sizeAsLongMax() == 0;
} catch (IllegalStateException e) {
throw DbException.get(ErrorCode.OBJECT_CLOSED, e);
}
}
@Override
public long getRowCount(Session session) {
TransactionMap<Value, Value> map = getMap(session);
return map.sizeAsLong();
}
@Override
public long getRowCountApproximation() {
try {
return dataMap.sizeAsLongMax();
} catch (IllegalStateException e) {
throw DbException.get(ErrorCode.OBJECT_CLOSED, e);
}
}
@Override
public long getDiskSpaceUsed() {
// TODO estimate disk space usage
return 0;
}
@Override
public boolean canFindNext() {
return true;
}
@Override
public Cursor findNext(Session session, SearchRow higherThan, SearchRow last) {
return find(session, higherThan, true, last);
}
@Override
public void checkRename() {
// ok
}
/**
* Get the map to store the data.
*
* @param session the session
* @return the map
*/
TransactionMap<Value, Value> getMap(Session session) {
if (session == null) {
return dataMap;
}
Transaction t = mvTable.getTransaction(session);
return dataMap.getInstance(t, Long.MAX_VALUE);
}
/**
* A cursor.
*/
class MVStoreCursor implements Cursor {
private final Session session;
private final Iterator<Value> it;
private final SearchRow last;
private Value current;
private SearchRow searchRow;
private Row row;
public MVStoreCursor(Session session, Iterator<Value> it, SearchRow last) {
this.session = session;
this.it = it;
this.last = last;
}
@Override
public Row get() {
if (row == null) {
SearchRow r = getSearchRow();
if (r != null) {
row = mvTable.getRow(session, r.getKey());
}
}
return row;
}
@Override
public SearchRow getSearchRow() {
if (searchRow == null) {
if (current != null) {
searchRow = convertToSearchRow((ValueArray) current);
}
}
return searchRow;
}
@Override
public boolean next() {
current = it.hasNext() ? it.next() : null;
searchRow = null;
if (current != null) {
if (last != null && compareRows(getSearchRow(), last) > 0) {
searchRow = null;
current = null;
}
}
row = null;
return current != null;
}
@Override
public boolean previous() {
throw DbException.getUnsupportedException("previous");
}
}
}