/**
* Returns the current transaction isolation level.
*
* @return the isolation level.
* @throws SQLException if the connection is closed
*/
public int getTransactionIsolation() throws SQLException {
try {
debugCodeCall("getTransactionIsolation");
checkClosed();
getLockMode = prepareCommand("CALL LOCK_MODE()", getLockMode);
ResultInterface result = getLockMode.executeQuery(0, false);
result.next();
int lockMode = result.currentRow()[0].getInt();
result.close();
int transactionIsolationLevel;
switch (lockMode) {
case Constants.LOCK_MODE_OFF:
transactionIsolationLevel = Connection.TRANSACTION_READ_UNCOMMITTED;
break;
case Constants.LOCK_MODE_READ_COMMITTED:
transactionIsolationLevel = Connection.TRANSACTION_READ_COMMITTED;
break;
case Constants.LOCK_MODE_TABLE:
case Constants.LOCK_MODE_TABLE_GC:
transactionIsolationLevel = Connection.TRANSACTION_SERIALIZABLE;
break;
default:
throw DbException.throwInternalError("lockMode:" + lockMode);
}
return transactionIsolationLevel;
} catch (Exception e) {
throw logAndConvert(e);
}
}
private int insertRows() {
session.getUser().checkRight(table, Right.INSERT);
setCurrentRowNumber(0);
table.fire(session, Trigger.INSERT, true);
rowNumber = 0;
int listSize = list.size();
if (listSize > 0) {
int columnLen = columns.length;
for (int x = 0; x < listSize; x++) {
Row newRow = table.getTemplateRow(); // newRow的长度是全表字段的个数是，会>=columns的长度
Expression[] expr = list.get(x);
setCurrentRowNumber(x + 1);
for (int i = 0; i < columnLen; i++) {
Column c = columns[i];
int index = c.getColumnId(); // 从0开始
Expression e = expr[i];
if (e != null) {
// e can be null (DEFAULT)
e = e.optimize(session);
try {
Value v = c.convert(e.getValue(session));
newRow.setValue(index, v);
} catch (DbException ex) {
throw setRow(ex, x, getSQL(expr));
}
}
}
rowNumber++;
table.validateConvertUpdateSequence(session, newRow);
boolean done = table.fireBeforeRow(session, null, newRow); // INSTEAD OF触发器会返回true
if (!done) {
// 直到事务commit或rollback时才解琐，见org.h2.engine.Session.unlockAll()
table.lock(session, true, false);
table.addRow(session, newRow);
// 在org.h2.index.PageDataIndex.addTry(Session, Row)中事先记了一次PageLog
// 也就是org.h2.store.PageStore.logAddOrRemoveRow(Session, int, Row, boolean)
// 这里又记了一次UndoLog
// UndoLog在org.h2.engine.Session.commit(boolean)时就清除了
session.log(table, UndoLogRecord.INSERT, newRow);
table.fireAfterRow(session, null, newRow, false);
}
}
} else {
table.lock(session, true, false);
// 这种方式主要是避免循环两次，因为query内部己循环一次了，得到记录后像else中的非insertFromSelect一样，还要循环一次
if (insertFromSelect) {
query.query(0, this); // 每遍历一行会回调下面的addRow方法
} else {
ResultInterface rows = query.query(0);
while (rows.next()) {
Value[] r = rows.currentRow();
addRow(r);
}
rows.close();
}
}
table.fire(session, Trigger.INSERT, false);
return rowNumber;
}
private boolean getInternalAutoCommit() {
getAutoCommit = prepareCommand("CALL AUTOCOMMIT()", getAutoCommit);
ResultInterface result = getAutoCommit.executeQuery(0, false);
result.next();
boolean autoCommit = result.currentRow()[0].getBoolean().booleanValue();
result.close();
return autoCommit;
}
private void checkNoNullValues() {
String sql =
"SELECT COUNT(*) FROM " + table.getSQL() + " WHERE " + oldColumn.getSQL() + " IS NULL";
Prepared command = session.prepare(sql);
ResultInterface result = command.query(0);
result.next();
if (result.currentRow()[0].getInt() > 0) {
throw DbException.get(ErrorCode.COLUMN_CONTAINS_NULL_VALUES_1, oldColumn.getSQL());
}
}
/**
* Returns true if the database is read-only.
*
* @return if the database is read-only
* @throws SQLException if the connection is closed
*/
public boolean isReadOnly() throws SQLException {
try {
debugCodeCall("isReadOnly");
checkClosed();
getReadOnly = prepareCommand("CALL READONLY()", getReadOnly);
ResultInterface result = getReadOnly.executeQuery(0, false);
result.next();
boolean readOnly = result.currentRow()[0].getBoolean().booleanValue();
return readOnly;
} catch (Exception e) {
throw logAndConvert(e);
}
}
private void sendRow(ResultInterface result) throws IOException {
if (result.next()) {
transfer.writeBoolean(true);
Value[] v = result.currentRow();
for (int i = 0; i < result.getVisibleColumnCount(); i++) {
if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_12) {
transfer.writeValue(v[i]);
} else {
writeValue(v[i]);
}
}
} else {
transfer.writeBoolean(false);
}
}
/**
* Gets the current catalog name.
*
* @return the catalog name
* @throws SQLException if the connection is closed
*/
public String getCatalog() throws SQLException {
try {
debugCodeCall("getCatalog");
checkClosed();
if (catalog == null) {
CommandInterface cat = prepareCommand("CALL DATABASE()", Integer.MAX_VALUE);
ResultInterface result = cat.executeQuery(0, false);
result.next();
catalog = result.currentRow()[0].getString();
cat.close();
}
return catalog;
} catch (Exception e) {
throw logAndConvert(e);
}
}
/**
* Read the serializer name from the persistent database settings.
*
* @return the serializer
*/
private String readSerializationSettings() {
String javaObjectSerializerFQN = null;
CommandInterface ci =
prepareCommand(
"SELECT VALUE FROM INFORMATION_SCHEMA.SETTINGS "
+ " WHERE NAME='JAVA_OBJECT_SERIALIZER'",
Integer.MAX_VALUE);
try {
ResultInterface result = ci.executeQuery(0, false);
if (result.next()) {
Value[] row = result.currentRow();
javaObjectSerializerFQN = row[0].getString();
}
} finally {
ci.close();
}
return javaObjectSerializerFQN;
}
/** INTERNAL */
public int getQueryTimeout() throws SQLException {
try {
debugCodeCall("getQueryTimeout");
checkClosed();
getQueryTimeout =
prepareCommand(
"SELECT VALUE FROM INFORMATION_SCHEMA.SETTINGS WHERE NAME=?", getQueryTimeout);
getQueryTimeout.getParameters().get(0).setValue(ValueString.get("QUERY_TIMEOUT"), false);
ResultInterface result = getQueryTimeout.executeQuery(0, false);
result.next();
int queryTimeout = result.currentRow()[0].getInt();
result.close();
if (queryTimeout == 0) {
return 0;
}
// round to the next second, otherwise 999 millis would return 0 seconds
return (queryTimeout + 999) / 1000;
} catch (Exception e) {
throw logAndConvert(e);
}
}
@Override
public Value getValue(Session session) {
query.setSession(session);
ResultInterface result = query.query(2);
try {
int rowcount = result.getRowCount();
if (rowcount > 1) {
throw DbException.get(ErrorCode.SCALAR_SUBQUERY_CONTAINS_MORE_THAN_ONE_ROW);
}
Value v;
if (rowcount <= 0) {
v = ValueNull.INSTANCE;
} else {
result.next();
Value[] values = result.currentRow();
if (result.getVisibleColumnCount() == 1) {
v = values[0];
} else {
v = ValueArray.get(values);
}
}
return v;
} finally {
result.close();
}
}
// 总共18条命令，这里包含16条
// 下面这两条在run方法中特殊处理
// SESSION_CANCEL_STATEMENT
// SESSION_CHECK_KEY
// 分三种级别，从大到小: SESSION级、COMMAND级、RESULT级
private void process() throws IOException {
int operation = transfer.readInt();
switch (operation) {
case SessionRemote.SESSION_PREPARE_READ_PARAMS:
case SessionRemote.SESSION_PREPARE:
{
int id = transfer.readInt();
String sql = transfer.readString();
int old = session.getModificationId();
Command command = session.prepareLocal(sql);
boolean readonly = command.isReadOnly();
cache.addObject(id, command);
boolean isQuery = command.isQuery();
ArrayList<? extends ParameterInterface> params = command.getParameters();
transfer
.writeInt(getState(old))
.writeBoolean(isQuery)
.writeBoolean(readonly)
.writeInt(params.size());
if (operation == SessionRemote.SESSION_PREPARE_READ_PARAMS) {
for (ParameterInterface p : params) {
ParameterRemote.writeMetaData(transfer, p);
}
}
transfer.flush();
break;
}
case SessionRemote.SESSION_CLOSE:
{
stop = true;
closeSession();
transfer.writeInt(SessionRemote.STATUS_OK).flush();
close();
break;
}
case SessionRemote.COMMAND_COMMIT:
{
// 并不是通过org.h2.jdbc.JdbcConnection.commit()触发，此方法是通过发送COMMIT SQL触发
// 触发SessionRemote.COMMAND_COMMIT的是在集群环境下，通过org.h2.engine.SessionRemote.autoCommitIfCluster()触发
if (commit == null) {
commit = session.prepareLocal("COMMIT");
}
int old = session.getModificationId();
commit.executeUpdate();
transfer.writeInt(getState(old)).flush();
break;
}
case SessionRemote.COMMAND_GET_META_DATA:
{
int id = transfer.readInt();
int objectId = transfer.readInt();
Command command = (Command) cache.getObject(id, false);
ResultInterface result = command.getMetaData();
cache.addObject(objectId, result);
int columnCount = result.getVisibleColumnCount();
transfer.writeInt(SessionRemote.STATUS_OK).writeInt(columnCount).writeInt(0);
for (int i = 0; i < columnCount; i++) {
ResultColumn.writeColumn(transfer, result, i);
}
transfer.flush();
break;
}
case SessionRemote.COMMAND_EXECUTE_QUERY:
{
int id = transfer.readInt();
int objectId = transfer.readInt();
int maxRows = transfer.readInt();
int fetchSize = transfer.readInt();
Command command = (Command) cache.getObject(id, false);
setParameters(command);
int old = session.getModificationId();
ResultInterface result;
synchronized (session) {
result = command.executeQuery(maxRows, false);
}
cache.addObject(objectId, result);
int columnCount = result.getVisibleColumnCount();
int state = getState(old);
transfer.writeInt(state).writeInt(columnCount);
int rowCount = result.getRowCount();
transfer.writeInt(rowCount);
for (int i = 0; i < columnCount; i++) {
ResultColumn.writeColumn(transfer, result, i);
}
int fetch = Math.min(rowCount, fetchSize);
for (int i = 0; i < fetch; i++) {
sendRow(result);
}
transfer.flush();
break;
}
case SessionRemote.COMMAND_EXECUTE_UPDATE:
{
int id = transfer.readInt();
Command command = (Command) cache.getObject(id, false);
// if(command!=null)throw new Error();
setParameters(command);
int old = session.getModificationId();
int updateCount;
synchronized (session) {
updateCount = command.executeUpdate();
}
int status;
if (session.isClosed()) {
status = SessionRemote.STATUS_CLOSED;
} else {
status = getState(old);
}
transfer.writeInt(status).writeInt(updateCount).writeBoolean(session.getAutoCommit());
transfer.flush();
break;
}
case SessionRemote.COMMAND_CLOSE:
{
int id = transfer.readInt();
Command command = (Command) cache.getObject(id, true);
if (command != null) {
command.close();
cache.freeObject(id);
}
break;
}
case SessionRemote.RESULT_FETCH_ROWS:
{
int id = transfer.readInt();
int count = transfer.readInt();
ResultInterface result = (ResultInterface) cache.getObject(id, false);
transfer.writeInt(SessionRemote.STATUS_OK);
for (int i = 0; i < count; i++) {
sendRow(result);
}
transfer.flush();
break;
}
case SessionRemote.RESULT_RESET:
{
int id = transfer.readInt();
ResultInterface result = (ResultInterface) cache.getObject(id, false);
result.reset();
break;
}
case SessionRemote.RESULT_CLOSE:
{
int id = transfer.readInt();
ResultInterface result = (ResultInterface) cache.getObject(id, true);
if (result != null) {
result.close();
cache.freeObject(id);
}
break;
}
case SessionRemote.CHANGE_ID:
{
int oldId = transfer.readInt();
int newId = transfer.readInt();
Object obj = cache.getObject(oldId, false);
cache.freeObject(oldId);
cache.addObject(newId, obj);
break;
}
case SessionRemote.SESSION_SET_ID:
{
sessionId = transfer.readString();
transfer.writeInt(SessionRemote.STATUS_OK).flush();
break;
}
case SessionRemote.SESSION_SET_AUTOCOMMIT:
{
boolean autoCommit = transfer.readBoolean();
session.setAutoCommit(autoCommit);
transfer.writeInt(SessionRemote.STATUS_OK).flush();
break;
}
case SessionRemote.SESSION_HAS_PENDING_TRANSACTION:
{
transfer
.writeInt(SessionRemote.STATUS_OK)
.writeInt(session.hasPendingTransaction() ? 1 : 0)
.flush();
break;
}
case SessionRemote.LOB_READ:
{
long lobId = transfer.readLong();
byte[] hmac;
CachedInputStream in;
boolean verifyMac;
if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_11) {
if (clientVersion >= Constants.TCP_PROTOCOL_VERSION_12) {
hmac = transfer.readBytes();
verifyMac = true;
} else {
hmac = null;
verifyMac = false;
}
in = lobs.get(lobId);
if (in == null && verifyMac) {
in = new CachedInputStream(null);
lobs.put(lobId, in);
}
} else {
verifyMac = false;
hmac = null;
in = lobs.get(lobId);
}
long offset = transfer.readLong();
int length = transfer.readInt();
if (verifyMac) {
transfer.verifyLobMac(hmac, lobId);
}
if (in == null) {
throw DbException.get(ErrorCode.OBJECT_CLOSED);
}
if (in.getPos() != offset) {
LobStorageInterface lobStorage = session.getDataHandler().getLobStorage();
InputStream lobIn = lobStorage.getInputStream(lobId, hmac, -1);
in = new CachedInputStream(lobIn);
lobs.put(lobId, in);
lobIn.skip(offset);
}
// limit the buffer size
length = Math.min(16 * Constants.IO_BUFFER_SIZE, length);
byte[] buff = new byte[length];
length = IOUtils.readFully(in, buff, 0, length);
transfer.writeInt(SessionRemote.STATUS_OK);
transfer.writeInt(length);
transfer.writeBytes(buff, 0, length);
transfer.flush();
break;
}
default:
trace("Unknown operation: " + operation);
closeSession();
close();
}
}
@Override
protected LocalResult queryWithoutCache(int maxRows, ResultTarget target) {
if (maxRows != 0) {
// maxRows is set (maxRows 0 means no limit)
int l;
if (limitExpr == null) {
l = -1;
} else {
Value v = limitExpr.getValue(session);
l = v == ValueNull.INSTANCE ? -1 : v.getInt();
}
if (l < 0) {
// for limitExpr, 0 means no rows, and -1 means no limit
l = maxRows;
} else {
l = Math.min(l, maxRows);
}
limitExpr = ValueExpression.get(ValueInt.get(l));
}
if (session.getDatabase().getSettings().optimizeInsertFromSelect) {
if (unionType == UNION_ALL && target != null) {
if (sort == null && !distinct && maxRows == 0 && offsetExpr == null && limitExpr == null) {
left.query(0, target);
right.query(0, target);
return null;
}
}
}
int columnCount = left.getColumnCount();
LocalResult result = new LocalResult(session, expressionArray, columnCount);
if (sort != null) {
result.setSortOrder(sort);
}
if (distinct) {
left.setDistinct(true);
right.setDistinct(true);
result.setDistinct();
}
if (randomAccessResult) {
result.setRandomAccess();
}
switch (unionType) {
case UNION:
case EXCEPT:
left.setDistinct(true);
right.setDistinct(true);
result.setDistinct();
break;
case UNION_ALL:
break;
case INTERSECT:
left.setDistinct(true);
right.setDistinct(true);
break;
default:
DbException.throwInternalError("type=" + unionType);
}
ResultInterface l = left.query(0);
ResultInterface r = right.query(0);
l.reset();
r.reset();
switch (unionType) {
case UNION_ALL:
case UNION:
{
while (l.next()) {
result.addRow(convert(l.currentRow(), columnCount));
}
while (r.next()) {
result.addRow(convert(r.currentRow(), columnCount));
}
break;
}
case EXCEPT:
{
while (l.next()) {
result.addRow(convert(l.currentRow(), columnCount));
}
while (r.next()) {
result.removeDistinct(convert(r.currentRow(), columnCount));
}
break;
}
case INTERSECT:
{
LocalResult temp = new LocalResult(session, expressionArray, columnCount);
temp.setDistinct();
temp.setRandomAccess();
while (l.next()) {
temp.addRow(convert(l.currentRow(), columnCount));
}
while (r.next()) {
Value[] values = convert(r.currentRow(), columnCount);
if (temp.containsDistinct(values)) {
result.addRow(values);
}
}
break;
}
default:
DbException.throwInternalError("type=" + unionType);
}
if (offsetExpr != null) {
result.setOffset(offsetExpr.getValue(session).getInt());
}
if (limitExpr != null) {
Value v = limitExpr.getValue(session);
if (v != ValueNull.INSTANCE) {
result.setLimit(v.getInt());
}
}
result.done();
if (target != null) {
while (result.next()) {
target.addRow(result.currentRow());
}
result.close();
return null;
}
return result;
}
public Cursor find(Session session, SearchRow first, SearchRow last) {
if (recursive) {
if (view.getRecursiveResult() != null) {
ResultInterface r = view.getRecursiveResult();
r.reset();
return new ViewCursor(table, r);
}
if (query == null) {
query = (Query) createSession.prepare(querySQL, true);
planSQL = query.getPlanSQL();
}
if (!(query instanceof SelectUnion)) {
throw DbException.get(ErrorCode.SYNTAX_ERROR_2, "recursive queries without UNION ALL");
}
SelectUnion union = (SelectUnion) query;
if (union.getUnionType() != SelectUnion.UNION_ALL) {
throw DbException.get(ErrorCode.SYNTAX_ERROR_2, "recursive queries without UNION ALL");
}
Query left = union.getLeft();
ResultInterface r = left.query(0);
LocalResult result = union.getEmptyResult();
while (r.next()) {
result.addRow(r.currentRow());
}
Query right = union.getRight();
r.reset();
view.setRecursiveResult(r);
while (true) {
r = right.query(0);
if (r.getRowCount() == 0) {
break;
}
while (r.next()) {
result.addRow(r.currentRow());
}
r.reset();
view.setRecursiveResult(r);
}
return new ViewCursor(table, result);
}
ArrayList<Parameter> paramList = query.getParameters();
for (int i = 0; originalParameters != null && i < originalParameters.size(); i++) {
Parameter orig = originalParameters.get(i);
int idx = orig.getIndex();
Value value = orig.getValue(session);
setParameter(paramList, idx, value);
}
int len;
if (first != null) {
len = first.getColumnCount();
} else if (last != null) {
len = last.getColumnCount();
} else {
len = 0;
}
int idx = originalParameters == null ? 0 : originalParameters.size();
idx += view.getParameterOffset();
for (int i = 0; i < len; i++) {
if (first != null) {
Value v = first.getValue(i);
if (v != null) {
int x = idx++;
setParameter(paramList, x, v);
}
}
// for equality, only one parameter is used (first == last)
if (last != null && indexMasks[i] != IndexCondition.EQUALITY) {
Value v = last.getValue(i);
if (v != null) {
int x = idx++;
setParameter(paramList, x, v);
}
}
}
ResultInterface result = query.query(0);
return new ViewCursor(table, result);
}