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/*
* Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.pagestore.db;
import org.h2.api.ErrorCode;
import org.h2.command.dml.AllColumnsForPlan;
import org.h2.engine.Constants;
import org.h2.engine.Session;
import org.h2.engine.SysProperties;
import org.h2.index.Cursor;
import org.h2.index.IndexType;
import org.h2.message.DbException;
import org.h2.pagestore.Page;
import org.h2.pagestore.PageStore;
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.MathUtils;
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 final PageStore store;
private final PageStoreTable tableData;
private long lastKey;
private long rowCount;
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;
public PageDataIndex(PageStoreTable table, int id, IndexColumn[] columns,
IndexType indexType, boolean create, Session session) {
super(table, id, table.getName() + "_DATA", columns, indexType);
// trace = database.getTrace(Trace.PAGE_STORE + "_di");
// trace.setLevel(TraceSystem.DEBUG);
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;
}
@Override
public DbException getDuplicateKeyException(String key) {
if (fastDuplicateKeyException == null) {
fastDuplicateKeyException = super.getDuplicateKeyException(null);
}
return fastDuplicateKeyException;
}
@Override
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.copy(database, getId());
if (v2.isLinkedToTable()) {
session.removeAtCommitStop(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) {
e = DbException.get(ErrorCode.DUPLICATE_KEY_1,
getDuplicatePrimaryKeyMessage(mainIndexColumn).toString());
e.setSource(this);
throw e;
}
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() * 10_000));
} else {
row.setKey(row.getKey() + add);
}
add++;
} finally {
store.incrementChangeCount();
}
}
lastKey = Math.max(lastKey, row.getKey());
}
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);
invalidateRowCount();
rowCount++;
store.logAddOrRemoveRow(session, tableData.getId(), row, true);
}
/**
* Read an overflow 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, String.valueOf(pd));
}
PageData p = (PageData) pd;
if (parent != -1) {
if (p.getParentPageId() != parent) {
throw DbException.throwInternalError(p +
" parent " + p.getParentPageId() + " expected " + parent);
}
}
return p;
}
@Override
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) {
return row.getKey();
} else if (v == ValueNull.INSTANCE) {
return ifNull;
}
return v.getLong();
}
@Override
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);
}
/**
* 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
* @return the cursor
*/
Cursor find(Session session, long first, long last) {
PageData root = getPage(rootPageId, 0);
return root.find(session, first, last);
}
@Override
public Cursor findFirstOrLast(Session session, boolean first) {
throw DbException.throwInternalError(toString());
}
long getLastKey() {
PageData root = getPage(rootPageId, 0);
return root.getLastKey();
}
@Override
public double getCost(Session session, int[] masks,
TableFilter[] filters, int filter, SortOrder sortOrder,
AllColumnsForPlan allColumnsSet) {
// The +200 is so that indexes that can return the same data, but have less
// columns, will take precedence. This all works out easier in the MVStore case,
// because MVStore uses the same cost calculation code for the ScanIndex (i.e.
// the MVPrimaryIndex) and all other indices.
return 10 * (tableData.getRowCountApproximation() +
Constants.COST_ROW_OFFSET) + 200;
}
@Override
public boolean needRebuild() {
return false;
}
@Override
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.isLinkedToTable()) {
session.removeAtCommit(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();
}
}
store.logAddOrRemoveRow(session, tableData.getId(), row, false);
}
@Override
public void remove(Session session) {
if (trace.isDebugEnabled()) {
trace.debug("{0} remove", this);
}
removeAllRows();
store.free(rootPageId);
store.removeMeta(this, session);
}
@Override
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());
}
tableData.setRowCount(0);
}
private void removeAllRows() {
try {
PageData root = getPage(rootPageId, 0);
root.freeRecursive();
root = PageDataLeaf.create(this, rootPageId, PageData.ROOT);
store.removeFromCache(rootPageId);
store.update(root);
rowCount = 0;
lastKey = 0;
} finally {
store.incrementChangeCount();
}
}
@Override
public void checkRename() {
throw DbException.getUnsupportedException("PAGE");
}
@Override
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;
}
@Override
public long getRowCountApproximation() {
return rowCount;
}
@Override
public long getRowCount(Session session) {
return rowCount;
}
@Override
public long getDiskSpaceUsed() {
PageData root = getPage(rootPageId, 0);
return root.getDiskSpaceUsed();
}
@Override
public String getCreateSQL() {
return null;
}
@Override
public int getColumnIndex(Column col) {
// can not use this index - use the PageDelegateIndex instead
return -1;
}
@Override
public boolean isFirstColumn(Column column) {
return false;
}
@Override
public void close(Session session) {
if (trace.isDebugEnabled()) {
trace.debug("{0} close", this);
}
// can not close the index because it might get used afterwards,
// for example after running recovery
writeRowCount();
}
/**
* 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;
}
@Override
public String toString() {
return getName();
}
private void invalidateRowCount() {
PageData root = getPage(rootPageId, 0);
root.setRowCountStored(PageData.UNKNOWN_ROWCOUNT);
}
@Override
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();
}
}
@Override
public String getPlanSQL() {
return table.getSQL(new StringBuilder(), false).append(".tableScan").toString();
}
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);
}
}
@Override
public boolean isRowIdIndex() {
return true;
}
}
