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/*
* Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.index;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import org.h2.constant.ErrorCode;
import org.h2.constant.SysProperties;
import org.h2.engine.Constants;
import org.h2.engine.Session;
import org.h2.engine.UndoLogRecord;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.store.Page;
import org.h2.store.PageStore;
import org.h2.table.Column;
import org.h2.table.IndexColumn;
import org.h2.table.RegularTable;
import org.h2.util.MathUtils;
import org.h2.util.New;
import org.h2.value.Value;
import org.h2.value.ValueNull;
/**
* The scan index allows to access a row by key. It can be used to iterate over
* all rows of a table. Each regular table has one such object, even if no
* primary key or indexes are defined.
*/
public class PageDataIndex extends PageIndex {
private PageStore store;
private RegularTable tableData;
private long lastKey;
private long rowCount;
private HashSet delta;
private int rowCountDiff;
private HashMap sessionRowCount;
private int mainIndexColumn = -1;
private DbException fastDuplicateKeyException;
/**
* The estimated heap memory per page, in number of double words (4 bytes
* each).
*/
private int memoryPerPage;
private int memoryCount;
private boolean multiVersion;
public PageDataIndex(RegularTable table, int id, IndexColumn[] columns,
IndexType indexType, boolean create, Session session) {
initBaseIndex(table, id, table.getName() + "_DATA", columns, indexType);
this.multiVersion = database.isMultiVersion();
// trace = database.getTrace(Trace.PAGE_STORE + "_di");
// trace.setLevel(TraceSystem.DEBUG);
if (multiVersion) {
sessionRowCount = New.hashMap();
isMultiVersion = true;
}
tableData = table;
this.store = database.getPageStore();
store.addIndex(this);
if (!database.isPersistent()) {
throw DbException.throwInternalError(table.getName());
}
if (create) {
rootPageId = store.allocatePage();
store.addMeta(this, session);
PageDataLeaf root = PageDataLeaf.create(this, rootPageId, PageData.ROOT);
store.update(root);
} else {
rootPageId = store.getRootPageId(id);
PageData root = getPage(rootPageId, 0);
lastKey = root.getLastKey();
rowCount = root.getRowCount();
}
if (trace.isDebugEnabled()) {
trace.debug("{0} opened rows: {1}", this, rowCount);
}
table.setRowCount(rowCount);
memoryPerPage = (Constants.MEMORY_PAGE_DATA + store.getPageSize()) >> 2;
}
public DbException getDuplicateKeyException() {
if (fastDuplicateKeyException == null) {
fastDuplicateKeyException = super.getDuplicateKeyException();
}
return fastDuplicateKeyException;
}
public void add(Session session, Row row) {
boolean retry = false;
if (mainIndexColumn != -1) {
row.setKey(row.getValue(mainIndexColumn).getLong());
} else {
if (row.getKey() == 0) {
row.setKey((int) ++lastKey);
retry = true;
}
}
if (tableData.getContainsLargeObject()) {
for (int i = 0, len = row.getColumnCount(); i < len; i++) {
Value v = row.getValue(i);
Value v2 = v.link(database, getId());
if (v2.isLinked()) {
session.unlinkAtCommitStop(v2);
}
if (v != v2) {
row.setValue(i, v2);
}
}
}
// when using auto-generated values, it's possible that multiple
// tries are required (specially if there was originally a primary key)
if (trace.isDebugEnabled()) {
trace.debug("{0} add {1}", getName(), row);
}
long add = 0;
while (true) {
try {
addTry(session, row);
break;
} catch (DbException e) {
if (e != fastDuplicateKeyException) {
throw e;
}
if (!retry) {
throw getNewDuplicateKeyException();
}
if (add == 0) {
// in the first re-try add a small random number,
// to avoid collisions after a re-start
row.setKey((long) (row.getKey() + Math.random() * 10000));
} else {
row.setKey(row.getKey() + add);
}
add++;
} finally {
store.incrementChangeCount();
}
}
lastKey = Math.max(lastKey, row.getKey());
}
public DbException getNewDuplicateKeyException() {
String sql = "PRIMARY KEY ON " + table.getSQL();
if (mainIndexColumn >= 0 && mainIndexColumn < indexColumns.length) {
sql += "(" + indexColumns[mainIndexColumn].getSQL() + ")";
}
DbException e = DbException.get(ErrorCode.DUPLICATE_KEY_1, sql);
e.setSource(this);
return e;
}
private void addTry(Session session, Row row) {
while (true) {
PageData root = getPage(rootPageId, 0);
int splitPoint = root.addRowTry(row);
if (splitPoint == -1) {
break;
}
if (trace.isDebugEnabled()) {
trace.debug("{0} split", this);
}
long pivot = splitPoint == 0 ? row.getKey() : root.getKey(splitPoint - 1);
PageData page1 = root;
PageData page2 = root.split(splitPoint);
int id = store.allocatePage();
page1.setPageId(id);
page1.setParentPageId(rootPageId);
page2.setParentPageId(rootPageId);
PageDataNode newRoot = PageDataNode.create(this, rootPageId, PageData.ROOT);
newRoot.init(page1, pivot, page2);
store.update(page1);
store.update(page2);
store.update(newRoot);
root = newRoot;
}
row.setDeleted(false);
if (multiVersion) {
if (delta == null) {
delta = New.hashSet();
}
boolean wasDeleted = delta.remove(row);
if (!wasDeleted) {
delta.add(row);
}
incrementRowCount(session.getId(), 1);
}
invalidateRowCount();
rowCount++;
store.logAddOrRemoveRow(session, tableData.getId(), row, true);
}
/**
* Read an overflow page page.
*
* @param id the page id
* @return the page
*/
PageDataOverflow getPageOverflow(int id) {
Page p = store.getPage(id);
if (p instanceof PageDataOverflow) {
return (PageDataOverflow) p;
}
throw DbException.get(ErrorCode.FILE_CORRUPTED_1, p == null ? "null" : p.toString());
}
/**
* Read the given page.
*
* @param id the page id
* @param parent the parent, or -1 if unknown
* @return the page
*/
PageData getPage(int id, int parent) {
Page pd = store.getPage(id);
if (pd == null) {
PageDataLeaf empty = PageDataLeaf.create(this, id, parent);
// could have been created before, but never committed
store.logUndo(empty, null);
store.update(empty);
return empty;
} else if (!(pd instanceof PageData)) {
throw DbException.get(ErrorCode.FILE_CORRUPTED_1, "" + pd);
}
PageData p = (PageData) pd;
if (parent != -1) {
if (p.getParentPageId() != parent) {
throw DbException.throwInternalError(p + " parent " + p.getParentPageId() + " expected " + parent);
}
}
return p;
}
public boolean canGetFirstOrLast() {
return false;
}
/**
* Get the key from the row.
*
* @param row the row
* @param ifEmpty the value to use if the row is empty
* @param ifNull the value to use if the column is NULL
* @return the key
*/
long getKey(SearchRow row, long ifEmpty, long ifNull) {
if (row == null) {
return ifEmpty;
}
Value v = row.getValue(mainIndexColumn);
if (v == null) {
throw DbException.throwInternalError(row.toString());
} else if (v == ValueNull.INSTANCE) {
return ifNull;
}
return v.getLong();
}
public Cursor find(Session session, SearchRow first, SearchRow last) {
long from = first == null ? Long.MIN_VALUE : first.getKey();
long to = last == null ? Long.MAX_VALUE : last.getKey();
PageData root = getPage(rootPageId, 0);
return root.find(session, from, to, isMultiVersion);
}
/**
* Search for a specific row or a set of rows.
*
* @param session the session
* @param first the key of the first row
* @param last the key of the last row
* @param multiVersion if mvcc should be used
* @return the cursor
*/
Cursor find(Session session, long first, long last, boolean multiVersion) {
PageData root = getPage(rootPageId, 0);
return root.find(session, first, last, multiVersion);
}
public Cursor findFirstOrLast(Session session, boolean first) {
throw DbException.throwInternalError();
}
long getLastKey() {
PageData root = getPage(rootPageId, 0);
return root.getLastKey();
}
public double getCost(Session session, int[] masks) {
long cost = 10 * (tableData.getRowCountApproximation() + Constants.COST_ROW_OFFSET);
return cost;
}
public boolean needRebuild() {
return false;
}
public void remove(Session session, Row row) {
if (tableData.getContainsLargeObject()) {
for (int i = 0, len = row.getColumnCount(); i < len; i++) {
Value v = row.getValue(i);
if (v.isLinked()) {
session.unlinkAtCommit(v);
}
}
}
if (trace.isDebugEnabled()) {
trace.debug("{0} remove {1}", getName(), row);
}
if (rowCount == 1) {
removeAllRows();
} else {
try {
long key = row.getKey();
PageData root = getPage(rootPageId, 0);
root.remove(key);
invalidateRowCount();
rowCount--;
} finally {
store.incrementChangeCount();
}
}
if (multiVersion) {
// if storage is null, the delete flag is not yet set
row.setDeleted(true);
if (delta == null) {
delta = New.hashSet();
}
boolean wasAdded = delta.remove(row);
if (!wasAdded) {
delta.add(row);
}
incrementRowCount(session.getId(), -1);
}
store.logAddOrRemoveRow(session, tableData.getId(), row, false);
}
public void remove(Session session) {
if (trace.isDebugEnabled()) {
trace.debug("{0} remove", this);
}
removeAllRows();
store.free(rootPageId);
store.removeMeta(this, session);
}
public void truncate(Session session) {
if (trace.isDebugEnabled()) {
trace.debug("{0} truncate", this);
}
store.logTruncate(session, tableData.getId());
removeAllRows();
if (tableData.getContainsLargeObject() && tableData.isPersistData()) {
// unfortunately, the data is gone on rollback
session.commit(false);
database.getLobStorage().removeAllForTable(table.getId());
}
if (multiVersion) {
sessionRowCount.clear();
}
tableData.setRowCount(0);
}
private void removeAllRows() {
try {
PageData root = getPage(rootPageId, 0);
root.freeRecursive();
root = PageDataLeaf.create(this, rootPageId, PageData.ROOT);
store.removeRecord(rootPageId);
store.update(root);
rowCount = 0;
lastKey = 0;
} finally {
store.incrementChangeCount();
}
}
public void checkRename() {
throw DbException.getUnsupportedException("PAGE");
}
public Row getRow(Session session, long key) {
return getRowWithKey(key);
}
/**
* Get the row with the given key.
*
* @param key the key
* @return the row
*/
public Row getRowWithKey(long key) {
PageData root = getPage(rootPageId, 0);
return root.getRowWithKey(key);
}
PageStore getPageStore() {
return store;
}
public long getRowCountApproximation() {
return rowCount;
}
public long getRowCount(Session session) {
if (multiVersion) {
Integer i = sessionRowCount.get(session.getId());
long count = i == null ? 0 : i.intValue();
count += rowCount;
count -= rowCountDiff;
return count;
}
return rowCount;
}
public String getCreateSQL() {
return null;
}
public int getColumnIndex(Column col) {
// can not use this index - use the PageDelegateIndex instead
return -1;
}
public void close(Session session) {
if (trace.isDebugEnabled()) {
trace.debug("{0} close", this);
}
if (delta != null) {
delta.clear();
}
rowCountDiff = 0;
if (sessionRowCount != null) {
sessionRowCount.clear();
}
// can not close the index because it might get used afterwards,
// for example after running recovery
writeRowCount();
}
Iterator getDelta() {
if (delta == null) {
List e = Collections.emptyList();
return e.iterator();
}
return delta.iterator();
}
private void incrementRowCount(int sessionId, int count) {
if (multiVersion) {
Integer id = sessionId;
Integer c = sessionRowCount.get(id);
int current = c == null ? 0 : c.intValue();
sessionRowCount.put(id, current + count);
rowCountDiff += count;
}
}
public void commit(int operation, Row row) {
if (multiVersion) {
if (delta != null) {
delta.remove(row);
}
incrementRowCount(row.getSessionId(), operation == UndoLogRecord.DELETE ? 1 : -1);
}
}
/**
* The root page has changed.
*
* @param session the session
* @param newPos the new position
*/
void setRootPageId(Session session, int newPos) {
store.removeMeta(this, session);
this.rootPageId = newPos;
store.addMeta(this, session);
store.addIndex(this);
}
public void setMainIndexColumn(int mainIndexColumn) {
this.mainIndexColumn = mainIndexColumn;
}
public int getMainIndexColumn() {
return mainIndexColumn;
}
public String toString() {
return getName();
}
private void invalidateRowCount() {
PageData root = getPage(rootPageId, 0);
root.setRowCountStored(PageData.UNKNOWN_ROWCOUNT);
}
public void writeRowCount() {
if (SysProperties.MODIFY_ON_WRITE && rootPageId == 0) {
// currently creating the index
return;
}
try {
PageData root = getPage(rootPageId, 0);
root.setRowCountStored(MathUtils.convertLongToInt(rowCount));
} finally {
store.incrementChangeCount();
}
}
public String getPlanSQL() {
return table.getSQL() + ".tableScan";
}
int getMemoryPerPage() {
return memoryPerPage;
}
/**
* The memory usage of a page was changed. The new value is used to adopt
* the average estimated memory size of a page.
*
* @param x the new memory size
*/
void memoryChange(int x) {
if (memoryCount < Constants.MEMORY_FACTOR) {
memoryPerPage += (x - memoryPerPage) / ++memoryCount;
} else {
memoryPerPage += (x > memoryPerPage ? 1 : -1) + ((x - memoryPerPage) / Constants.MEMORY_FACTOR);
}
}
public boolean isRowIdIndex() {
return true;
}
}
