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package org.hsqldb;
import org.hsqldb.HsqlNameManager.HsqlName;
import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.DoubleIntIndex;
import org.hsqldb.lib.HsqlDeque;
import org.hsqldb.lib.IntKeyHashMapConcurrent;
import org.hsqldb.lib.LongDeque;
import org.hsqldb.persist.CachedObject;
/**
* Manages rows involved in transactions
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.0.0
* @since 2.0.0
*/
public class TransactionManagerMV2PL extends TransactionManagerCommon
implements TransactionManager {
// functional unit - merged committed transactions
HsqlDeque committedTransactions = new HsqlDeque();
LongDeque committedTransactionTimestamps = new LongDeque();
public TransactionManagerMV2PL(Database db) {
database = db;
hasPersistence = database.logger.isLogged();
lobSession = database.sessionManager.getSysLobSession();
rowActionMap = new IntKeyHashMapConcurrent(10000);
txModel = MVLOCKS;
catalogNameList = new HsqlName[]{ database.getCatalogName() };
}
public long getGlobalChangeTimestamp() {
return globalChangeTimestamp.get();
}
public boolean isMVRows() {
return true;
}
public int getTransactionControl() {
return MVLOCKS;
}
public void setTransactionControl(Session session, int mode) {
writeLock.lock();
try {
// statement runs as transaction
if (liveTransactionTimestamps.size() == 1) {
switch (mode) {
case MVCC : {
TransactionManagerMVCC manager =
new TransactionManagerMVCC(database);
manager.globalChangeTimestamp.set(
globalChangeTimestamp.get());
manager.liveTransactionTimestamps.addLast(
session.transactionTimestamp);
database.txManager = manager;
break;
}
case MVLOCKS :
break;
case LOCKS : {
TransactionManager2PL manager =
new TransactionManager2PL(database);
manager.globalChangeTimestamp.set(
globalChangeTimestamp.get());
database.txManager = manager;
break;
}
}
return;
}
} finally {
writeLock.unlock();
}
throw Error.error(ErrorCode.X_25001);
}
public void completeActions(Session session) {
endActionTPL(session);
}
public boolean prepareCommitActions(Session session) {
Object[] list = session.rowActionList.getArray();
int limit = session.rowActionList.size();
writeLock.lock();
try {
session.actionTimestamp = nextChangeTimestamp();
for (int i = 0; i < limit; i++) {
RowAction action = (RowAction) list[i];
action.prepareCommit(session);
}
return true;
} finally {
writeLock.unlock();
}
}
public boolean commitTransaction(Session session) {
if (session.abortTransaction) {
return false;
}
int limit = session.rowActionList.size();
Object[] list = session.rowActionList.getArray();
writeLock.lock();
try {
endTransaction(session);
// new actionTimestamp used for commitTimestamp
session.actionTimestamp = nextChangeTimestamp();
for (int i = 0; i < limit; i++) {
RowAction action = (RowAction) list[i];
action.commit(session);
}
persistCommit(session, list, limit);
// session.actionTimestamp is the committed tx timestamp
if (getFirstLiveTransactionTimestamp() > session.actionTimestamp) {
mergeTransaction(session, list, 0, limit,
session.actionTimestamp);
finaliseRows(session, list, 0, limit, true);
} else {
list = session.rowActionList.toArray();
addToCommittedQueue(session, list);
}
endTransactionTPL(session);
} finally {
writeLock.unlock();
}
session.tempSet.clear();
if (session != lobSession && lobSession.rowActionList.size() > 0) {
lobSession.isTransaction = true;
lobSession.actionIndex = lobSession.rowActionList.size();
lobSession.commit(false);
}
return true;
}
public void rollback(Session session) {
writeLock.lock();
try {
session.abortTransaction = false;
session.actionTimestamp = nextChangeTimestamp();
rollbackPartial(session, 0, session.transactionTimestamp);
endTransaction(session);
endTransactionTPL(session);
} finally {
writeLock.unlock();
}
}
public void rollbackSavepoint(Session session, int index) {
long timestamp = session.sessionContext.savepointTimestamps.get(index);
Integer oi = (Integer) session.sessionContext.savepoints.get(index);
int start = oi.intValue();
while (session.sessionContext.savepoints.size() > index + 1) {
session.sessionContext.savepoints.remove(
session.sessionContext.savepoints.size() - 1);
session.sessionContext.savepointTimestamps.removeLast();
}
rollbackPartial(session, start, timestamp);
}
public void rollbackAction(Session session) {
rollbackPartial(session, session.actionIndex, session.actionTimestamp);
endActionTPL(session);
}
/**
* rollback the row actions from start index in list and
* the given timestamp
*/
void rollbackPartial(Session session, int start, long timestamp) {
Object[] list = session.rowActionList.getArray();
int limit = session.rowActionList.size();
if (start == limit) {
return;
}
for (int i = start; i < limit; i++) {
RowAction action = (RowAction) list[i];
if (action != null) {
action.rollback(session, timestamp);
} else {
System.out.println("null action in rollback " + start);
}
}
// rolled back transactions can always be merged as they have never been
// seen by other sessions
mergeRolledBackTransaction(session, timestamp, list, start, limit);
finaliseRows(session, list, start, limit, false);
session.rowActionList.setSize(start);
}
public RowAction addDeleteAction(Session session, Table table, Row row,
int[] colMap) {
RowAction action;
boolean newAction;
synchronized (row) {
newAction = row.rowAction == null;
action = RowAction.addDeleteAction(session, table, row, colMap);
}
session.rowActionList.add(action);
if (newAction) {
if (!row.isMemory()) {
rowActionMap.put(action.getPos(), action);
}
}
return action;
}
public void addInsertAction(Session session, Table table, Row row) {
RowAction action = row.rowAction;
if (action == null) {
System.out.println("null insert action " + session + " "
+ session.actionTimestamp);
}
session.rowActionList.add(action);
if (!row.isMemory()) {
rowActionMap.put(action.getPos(), action);
}
}
// functional unit - accessibility of rows
public boolean canRead(Session session, Row row, int mode, int[] colMap) {
RowAction action = row.rowAction;
if (action == null) {
return true;
}
return action.canRead(session, TransactionManager.ACTION_READ);
}
public boolean canRead(Session session, int id, int mode) {
RowAction action = (RowAction) rowActionMap.get(id);
return action == null ? true
: action.canRead(session,
TransactionManager.ACTION_READ);
}
/**
* add transaction info to a row just loaded from the cache. called only
* for CACHED tables
*/
public void setTransactionInfo(CachedObject object) {
Row row = (Row) object;
RowAction rowact = (RowAction) rowActionMap.get(row.position);
row.rowAction = rowact;
}
/**
* remove the transaction info
*/
public void removeTransactionInfo(CachedObject object) {
rowActionMap.remove(object.getPos());
}
/**
* add a list of actions to the end of queue
*/
void addToCommittedQueue(Session session, Object[] list) {
synchronized (committedTransactionTimestamps) {
// add the txList according to commit timestamp
committedTransactions.addLast(list);
// get session commit timestamp
committedTransactionTimestamps.addLast(session.actionTimestamp);
/* debug 190
if (committedTransactions.size() > 64) {
System.out.println("******* excessive transaction queue");
}
// debug 190 */
}
}
/**
* expire all committed transactions that are no longer in scope
*/
void mergeExpiredTransactions(Session session) {
long timestamp = getFirstLiveTransactionTimestamp();
while (true) {
long commitTimestamp = 0;
Object[] actions = null;
synchronized (committedTransactionTimestamps) {
if (committedTransactionTimestamps.isEmpty()) {
break;
}
commitTimestamp = committedTransactionTimestamps.getFirst();
if (commitTimestamp < timestamp) {
committedTransactionTimestamps.removeFirst();
actions = (Object[]) committedTransactions.removeFirst();
} else {
break;
}
}
mergeTransaction(session, actions, 0, actions.length,
commitTimestamp);
finaliseRows(session, actions, 0, actions.length, true);
}
}
public void beginTransaction(Session session) {
writeLock.lock();
try {
session.actionTimestamp = nextChangeTimestamp();
session.transactionTimestamp = session.actionTimestamp;
session.isTransaction = true;
liveTransactionTimestamps.addLast(session.transactionTimestamp);
transactionCount++;
} finally {
writeLock.unlock();
}
}
/**
* add session to the end of queue when a transaction starts
* (depending on isolation mode)
*/
public void beginAction(Session session, Statement cs) {
if (session.hasLocks(cs)) {
return;
}
writeLock.lock();
try {
boolean canProceed = setWaitedSessionsTPL(session, cs);
if (canProceed) {
if (session.tempSet.isEmpty()) {
lockTablesTPL(session, cs);
// we dont set other sessions that would now be waiting for this one too
} else {
setWaitingSessionTPL(session);
}
} else {
session.abortTransaction = true;
}
} finally {
writeLock.unlock();
}
}
/**
* add session to the end of queue when a transaction starts
* (depending on isolation mode)
*/
public void beginActionResume(Session session) {
writeLock.lock();
try {
session.actionTimestamp = nextChangeTimestamp();
if (!session.isTransaction) {
session.transactionTimestamp = session.actionTimestamp;
session.isTransaction = true;
liveTransactionTimestamps.addLast(session.actionTimestamp);
transactionCount++;
}
} finally {
writeLock.unlock();
}
}
/**
* remove session from queue when a transaction ends
* and expire any committed transactions
* that are no longer required. remove transactions ended before the first
* timestamp in liveTransactionsSession queue
*/
void endTransaction(Session session) {
long timestamp = session.transactionTimestamp;
session.isTransaction = false;
int index = liveTransactionTimestamps.indexOf(timestamp);
if (index >= 0) {
transactionCount--;
liveTransactionTimestamps.remove(index);
mergeExpiredTransactions(session);
}
}
// functional unit - list actions and translate id's
/**
* Return a lookup of all row ids for cached tables in transactions.
* For auto-defrag, as currently there will be no RowAction entries
* at the time of defrag.
*/
public DoubleIntIndex getTransactionIDList() {
return super.getTransactionIDList();
}
/**
* Convert row ID's for cached table rows in transactions
*/
public void convertTransactionIDs(DoubleIntIndex lookup) {
super.convertTransactionIDs(lookup);
}
}