/*
* 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.table;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Set;
import org.h2.api.DatabaseEventListener;
import org.h2.command.ddl.Analyze;
import org.h2.command.ddl.CreateTableData;
import org.h2.constant.ErrorCode;
import org.h2.constant.SysProperties;
import org.h2.constraint.Constraint;
import org.h2.constraint.ConstraintReferential;
import org.h2.engine.Constants;
import org.h2.engine.Database;
import org.h2.engine.DbObject;
import org.h2.engine.Session;
import org.h2.index.Cursor;
import org.h2.index.HashIndex;
import org.h2.index.Index;
import org.h2.index.IndexType;
import org.h2.index.MultiVersionIndex;
import org.h2.index.NonUniqueHashIndex;
import org.h2.index.PageBtreeIndex;
import org.h2.index.PageDataIndex;
import org.h2.index.PageDelegateIndex;
import org.h2.index.ScanIndex;
import org.h2.index.TreeIndex;
import org.h2.message.DbException;
import org.h2.message.Trace;
import org.h2.result.Row;
import org.h2.result.SortOrder;
import org.h2.schema.SchemaObject;
import org.h2.util.MathUtils;
import org.h2.util.New;
import org.h2.value.CompareMode;
import org.h2.value.DataType;
import org.h2.value.Value;
/**
* Most tables are an instance of this class. For this table, the data is stored
* in the database. The actual data is not kept here, instead it is kept in the
* indexes. There is at least one index, the scan index.
*/
public class RegularTable extends TableBase {
private Index scanIndex;
private long rowCount;
private volatile Session lockExclusive;
private HashSet<Session> lockShared = New.hashSet();
private Trace traceLock;
private final ArrayList<Index> indexes = New.arrayList();
private long lastModificationId;
private boolean containsLargeObject;
private PageDataIndex mainIndex;
private int changesSinceAnalyze;
private int nextAnalyze;
private Column rowIdColumn;
/**
* True if one thread ever was waiting to lock this table. This is to avoid
* calling notifyAll if no session was ever waiting to lock this table. If
* set, the flag stays. In theory, it could be reset, however not sure when.
*/
private boolean waitForLock;
public RegularTable(CreateTableData data) {
super(data);
nextAnalyze = database.getSettings().analyzeAuto;
this.isHidden = data.isHidden;
for (Column col : getColumns()) {
if (DataType.isLargeObject(col.getType())) {
containsLargeObject = true;
}
}
if (containsLargeObject) {
Database db = data.session.getDatabase();
if (!db.isStarting()) {
// the lob tables are already created
// if the database is starting
db.getLobStorage().init();
}
}
if (data.persistData && database.isPersistent()) {
mainIndex = new PageDataIndex(this, data.id,
IndexColumn.wrap(getColumns()),
IndexType.createScan(data.persistData),
data.create, data.session);
scanIndex = mainIndex;
} else {
scanIndex = new ScanIndex(this, data.id, IndexColumn.wrap(getColumns()), IndexType.createScan(data.persistData));
}
indexes.add(scanIndex);
traceLock = database.getTrace(Trace.LOCK);
}
public void close(Session session) {
for (Index index : indexes) {
index.close(session);
}
}
/**
* Read the given row.
*
* @param session the session
* @param key unique key
* @return the row
*/
public Row getRow(Session session, long key) {
return scanIndex.getRow(session, key);
}
public void addRow(Session session, Row row) {
int i = 0;
lastModificationId = database.getNextModificationDataId();
if (database.isMultiVersion()) {
row.setSessionId(session.getId());
}
try {
for (int size = indexes.size(); i < size; i++) {
Index index = indexes.get(i);
index.add(session, row);
checkRowCount(session, index, 1);
}
rowCount++;
} catch (Throwable e) {
try {
while (--i >= 0) {
Index index = indexes.get(i);
index.remove(session, row);
checkRowCount(session, index, 0);
}
} catch (DbException e2) {
// this could happen, for example on failure in the storage
// but if that is not the case it means there is something wrong
// with the database
trace.error(e2, "could not undo operation");
throw e2;
}
DbException de = DbException.convert(e);
if (de.getErrorCode() == ErrorCode.DUPLICATE_KEY_1) {
for (int j = 0; j < indexes.size(); j++) {
Index index = indexes.get(j);
if (index.getIndexType().isUnique() && index instanceof MultiVersionIndex) {
MultiVersionIndex mv = (MultiVersionIndex) index;
if (mv.isUncommittedFromOtherSession(session, row)) {
throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, index.getName());
}
}
}
}
throw de;
}
analyzeIfRequired(session);
}
public void commit(short operation, Row row) {
lastModificationId = database.getNextModificationDataId();
for (int i = 0, size = indexes.size(); i < size; i++) {
Index index = indexes.get(i);
index.commit(operation, row);
}
}
private void checkRowCount(Session session, Index index, int offset) {
if (SysProperties.CHECK && !database.isMultiVersion()) {
if (!(index instanceof PageDelegateIndex)) {
long rc = index.getRowCount(session);
if (rc != rowCount + offset) {
DbException.throwInternalError(
"rowCount expected " + (rowCount + offset) +
" got " + rc + " " + getName() + "." + index.getName());
}
}
}
}
public Index getScanIndex(Session session) {
return indexes.get(0);
}
public Index getUniqueIndex() {
for (Index idx : indexes) {
if (idx.getIndexType().isUnique()) {
return idx;
}
}
return null;
}
public ArrayList<Index> getIndexes() {
return indexes;
}
public Index addIndex(Session session, String indexName, int indexId, IndexColumn[] cols, IndexType indexType,
boolean create, String indexComment) {
if (indexType.isPrimaryKey()) {
for (IndexColumn c : cols) {
Column column = c.column;
if (column.isNullable()) {
throw DbException.get(ErrorCode.COLUMN_MUST_NOT_BE_NULLABLE_1, column.getName());
}
column.setPrimaryKey(true);
}
}
Index index;
if (isPersistIndexes() && indexType.isPersistent()) {
int mainIndexColumn;
if (database.isStarting() && database.getPageStore().getRootPageId(indexId) != 0) {
mainIndexColumn = -1;
} else if (!database.isStarting() && mainIndex.getRowCount(session) != 0) {
mainIndexColumn = -1;
} else {
mainIndexColumn = getMainIndexColumn(indexType, cols);
}
if (mainIndexColumn != -1) {
mainIndex.setMainIndexColumn(mainIndexColumn);
index = new PageDelegateIndex(this, indexId, indexName, indexType, mainIndex, create, session);
} else {
index = new PageBtreeIndex(this, indexId, indexName, cols, indexType, create, session);
}
} else {
if (indexType.isHash() && cols.length <= 1) {
if (indexType.isUnique()) {
index = new HashIndex(this, indexId, indexName, cols, indexType);
} else {
index = new NonUniqueHashIndex(this, indexId, indexName, cols, indexType);
}
} else {
index = new TreeIndex(this, indexId, indexName, cols, indexType);
}
}
if (database.isMultiVersion()) {
index = new MultiVersionIndex(index, this);
}
if (index.needRebuild() && rowCount > 0) {
try {
Index scan = getScanIndex(session);
long remaining = scan.getRowCount(session);
long total = remaining;
Cursor cursor = scan.find(session, null, null);
long i = 0;
int bufferSize = (int) Math.min(rowCount, Constants.DEFAULT_MAX_MEMORY_ROWS);
ArrayList<Row> buffer = New.arrayList(bufferSize);
String n = getName() + ":" + index.getName();
int t = MathUtils.convertLongToInt(total);
while (cursor.next()) {
database.setProgress(DatabaseEventListener.STATE_CREATE_INDEX, n,
MathUtils.convertLongToInt(i++), t);
Row row = cursor.get();
buffer.add(row);
if (buffer.size() >= bufferSize) {
addRowsToIndex(session, buffer, index);
}
remaining--;
}
addRowsToIndex(session, buffer, index);
if (SysProperties.CHECK && remaining != 0) {
DbException.throwInternalError("rowcount remaining=" + remaining + " " + getName());
}
} catch (DbException e) {
getSchema().freeUniqueName(indexName);
try {
index.remove(session);
} catch (DbException e2) {
// this could happen, for example on failure in the storage
// but if that is not the case it means
// there is something wrong with the database
trace.error(e2, "could not remove index");
throw e2;
}
throw e;
}
}
boolean temporary = isTemporary();
index.setTemporary(temporary);
if (index.getCreateSQL() != null) {
index.setComment(indexComment);
if (temporary && !isGlobalTemporary()) {
session.addLocalTempTableIndex(index);
} else {
database.addSchemaObject(session, index);
}
}
indexes.add(index);
setModified();
return index;
}
private int getMainIndexColumn(IndexType indexType, IndexColumn[] cols) {
if (mainIndex.getMainIndexColumn() != -1) {
return -1;
}
if (!indexType.isPrimaryKey() || cols.length != 1) {
return -1;
}
IndexColumn first = cols[0];
if (first.sortType != SortOrder.ASCENDING) {
return -1;
}
switch(first.column.getType()) {
case Value.BYTE:
case Value.SHORT:
case Value.INT:
case Value.LONG:
break;
default:
return -1;
}
return first.column.getColumnId();
}
public boolean canGetRowCount() {
return true;
}
private static void addRowsToIndex(Session session, ArrayList<Row> list, Index index) {
final Index idx = index;
Collections.sort(list, new Comparator<Row>() {
public int compare(Row r1, Row r2) {
return idx.compareRows(r1, r2);
}
});
for (Row row : list) {
index.add(session, row);
}
list.clear();
}
public boolean canDrop() {
return true;
}
public long getRowCount(Session session) {
if (database.isMultiVersion()) {
return getScanIndex(session).getRowCount(session);
}
return rowCount;
}
public void removeRow(Session session, Row row) {
if (database.isMultiVersion()) {
if (row.isDeleted()) {
throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, getName());
}
int old = row.getSessionId();
int newId = session.getId();
if (old == 0) {
row.setSessionId(newId);
} else if (old != newId) {
throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, getName());
}
}
lastModificationId = database.getNextModificationDataId();
int i = indexes.size() - 1;
try {
for (; i >= 0; i--) {
Index index = indexes.get(i);
index.remove(session, row);
checkRowCount(session, index, -1);
}
rowCount--;
} catch (Throwable e) {
try {
while (++i < indexes.size()) {
Index index = indexes.get(i);
index.add(session, row);
checkRowCount(session, index, 0);
}
} catch (DbException e2) {
// this could happen, for example on failure in the storage
// but if that is not the case it means there is something wrong
// with the database
trace.error(e2, "could not undo operation");
throw e2;
}
throw DbException.convert(e);
}
analyzeIfRequired(session);
}
public void truncate(Session session) {
lastModificationId = database.getNextModificationDataId();
for (int i = indexes.size() - 1; i >= 0; i--) {
Index index = indexes.get(i);
index.truncate(session);
}
rowCount = 0;
changesSinceAnalyze = 0;
}
private void analyzeIfRequired(Session session) {
if (nextAnalyze == 0 || nextAnalyze > changesSinceAnalyze++) {
return;
}
changesSinceAnalyze = 0;
int n = 2 * nextAnalyze;
if (n > 0) {
nextAnalyze = n;
}
int rows = session.getDatabase().getSettings().analyzeSample;
Analyze.analyzeTable(session, this, rows, false);
}
public boolean isLockedExclusivelyBy(Session session) {
return lockExclusive == session;
}
public void lock(Session session, boolean exclusive, boolean force) {
int lockMode = database.getLockMode();
if (lockMode == Constants.LOCK_MODE_OFF) {
return;
}
if (!force && database.isMultiVersion()) {
// MVCC: update, delete, and insert use a shared lock.
// Select doesn't lock except when using FOR UPDATE and
// the system property h2.selectForUpdateMvcc
// is not enabled
if (exclusive) {
exclusive = false;
} else {
if (lockExclusive == null) {
return;
}
}
}
if (lockExclusive == session) {
return;
}
synchronized (database) {
try {
doLock(session, lockMode, exclusive);
} finally {
session.setWaitForLock(null);
}
}
}
private void doLock(Session session, int lockMode, boolean exclusive) {
traceLock(session, exclusive, "requesting for");
// don't get the current time unless necessary
long max = 0;
boolean checkDeadlock = false;
while (true) {
if (lockExclusive == session) {
return;
}
if (exclusive) {
if (lockExclusive == null) {
if (lockShared.isEmpty()) {
traceLock(session, exclusive, "added for");
session.addLock(this);
lockExclusive = session;
return;
} else if (lockShared.size() == 1 && lockShared.contains(session)) {
traceLock(session, exclusive, "add (upgraded) for ");
lockExclusive = session;
return;
}
}
} else {
if (lockExclusive == null) {
if (lockMode == Constants.LOCK_MODE_READ_COMMITTED) {
if (!database.isMultiThreaded() && !database.isMultiVersion()) {
// READ_COMMITTED: a read lock is acquired,
// but released immediately after the operation
// is complete.
// When allowing only one thread, no lock is
// required.
// Row level locks work like read committed.
return;
}
}
if (!lockShared.contains(session)) {
traceLock(session, exclusive, "ok");
session.addLock(this);
lockShared.add(session);
}
return;
}
}
session.setWaitForLock(this);
if (checkDeadlock) {
ArrayList<Session> sessions = checkDeadlock(session, null, null);
if (sessions != null) {
throw DbException.get(ErrorCode.DEADLOCK_1, getDeadlockDetails(sessions));
}
} else {
// check for deadlocks from now on
checkDeadlock = true;
}
long now = System.currentTimeMillis();
if (max == 0) {
// try at least one more time
max = now + session.getLockTimeout();
} else if (now >= max) {
traceLock(session, exclusive, "timeout after " + session.getLockTimeout());
throw DbException.get(ErrorCode.LOCK_TIMEOUT_1, getName());
}
try {
traceLock(session, exclusive, "waiting for");
if (database.getLockMode() == Constants.LOCK_MODE_TABLE_GC) {
for (int i = 0; i < 20; i++) {
long free = Runtime.getRuntime().freeMemory();
System.gc();
long free2 = Runtime.getRuntime().freeMemory();
if (free == free2) {
break;
}
}
}
// don't wait too long so that deadlocks are detected early
long sleep = Math.min(Constants.DEADLOCK_CHECK, max - now);
if (sleep == 0) {
sleep = 1;
}
waitForLock = true;
database.wait(sleep);
} catch (InterruptedException e) {
// ignore
}
}
}
private static String getDeadlockDetails(ArrayList<Session> sessions) {
StringBuilder buff = new StringBuilder();
for (Session s : sessions) {
Table lock = s.getWaitForLock();
buff.append("\nSession ").
append(s.toString()).
append(" is waiting to lock ").
append(lock.toString()).
append(" while locking ");
int i = 0;
for (Table t : s.getLocks()) {
if (i++ > 0) {
buff.append(", ");
}
buff.append(t.toString());
if (t instanceof RegularTable) {
if (((RegularTable) t).lockExclusive == s) {
buff.append(" (exclusive)");
} else {
buff.append(" (shared)");
}
}
}
buff.append('.');
}
return buff.toString();
}
public ArrayList<Session> checkDeadlock(Session session, Session clash, Set<Session> visited) {
// only one deadlock check at any given time
synchronized (RegularTable.class) {
if (clash == null) {
// verification is started
clash = session;
visited = New.hashSet();
} else if (clash == session) {
// we found a circle where this session is involved
return New.arrayList();
} else if (visited.contains(session)) {
// we have already checked this session.
// there is a circle, but the sessions in the circle need to
// find it out themselves
return null;
}
visited.add(session);
ArrayList<Session> error = null;
for (Session s : lockShared) {
if (s == session) {
// it doesn't matter if we have locked the object already
continue;
}
Table t = s.getWaitForLock();
if (t != null) {
error = t.checkDeadlock(s, clash, visited);
if (error != null) {
error.add(session);
break;
}
}
}
if (error == null && lockExclusive != null) {
Table t = lockExclusive.getWaitForLock();
if (t != null) {
error = t.checkDeadlock(lockExclusive, clash, visited);
if (error != null) {
error.add(session);
}
}
}
return error;
}
}
private void traceLock(Session session, boolean exclusive, String s) {
if (traceLock.isDebugEnabled()) {
traceLock.debug("{0} {1} {2} {3}", session.getId(),
exclusive ? "exclusive write lock" : "shared read lock", s, getName());
}
}
public boolean isLockedExclusively() {
return lockExclusive != null;
}
public void unlock(Session s) {
if (database != null) {
traceLock(s, lockExclusive == s, "unlock");
if (lockExclusive == s) {
lockExclusive = null;
}
if (lockShared.size() > 0) {
lockShared.remove(s);
}
// TODO lock: maybe we need we fifo-queue to make sure nobody
// starves. check what other databases do
synchronized (database) {
if (database.getSessionCount() > 1 && waitForLock) {
database.notifyAll();
}
}
}
}
/**
* Create a row from the values.
*
* @param data the value list
* @return the row
*/
public static Row createRow(Value[] data) {
return new Row(data, Row.MEMORY_CALCULATE);
}
/**
* Set the row count of this table.
*
* @param count the row count
*/
public void setRowCount(long count) {
this.rowCount = count;
}
public void removeChildrenAndResources(Session session) {
super.removeChildrenAndResources(session);
// go backwards because database.removeIndex will call table.removeIndex
while (indexes.size() > 1) {
Index index = indexes.get(1);
if (index.getName() != null) {
database.removeSchemaObject(session, index);
}
}
if (SysProperties.CHECK) {
for (SchemaObject obj : database.getAllSchemaObjects(DbObject.INDEX)) {
Index index = (Index) obj;
if (index.getTable() == this) {
DbException.throwInternalError("index not dropped: " + index.getName());
}
}
}
scanIndex.remove(session);
database.removeMeta(session, getId());
if (containsLargeObject) {
database.getLobStorage().removeAllForTable(getId());
}
scanIndex = null;
lockExclusive = null;
lockShared = null;
invalidate();
}
public String toString() {
return getSQL();
}
public void checkRename() {
// ok
}
public void checkSupportAlter() {
// ok
}
public boolean canTruncate() {
if (getCheckForeignKeyConstraints() && database.getReferentialIntegrity()) {
ArrayList<Constraint> constraints = getConstraints();
if (constraints != null) {
for (int i = 0, size = constraints.size(); i < size; i++) {
Constraint c = constraints.get(i);
if (!(c.getConstraintType().equals(Constraint.REFERENTIAL))) {
continue;
}
ConstraintReferential ref = (ConstraintReferential) c;
if (ref.getRefTable() == this) {
return false;
}
}
}
}
return true;
}
public String getTableType() {
return Table.TABLE;
}
public long getMaxDataModificationId() {
return lastModificationId;
}
public boolean getContainsLargeObject() {
return containsLargeObject;
}
public long getRowCountApproximation() {
return scanIndex.getRowCountApproximation();
}
public void setCompareMode(CompareMode compareMode) {
this.compareMode = compareMode;
}
public boolean isDeterministic() {
return true;
}
public Column getRowIdColumn() {
if (rowIdColumn == null) {
rowIdColumn = new Column(Column.ROWID, Value.LONG);
rowIdColumn.setTable(this, -1);
}
return rowIdColumn;
}
}