/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2002-2006
* Sleepycat Software. All rights reserved.
*
* $Id: Txn.java,v 1.141 2006/01/19 20:42:32 mark Exp $
*/
package com.sleepycat.je.txn;
import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.transaction.xa.XAResource;
import javax.transaction.xa.Xid;
import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.DbInternal;
import com.sleepycat.je.LockStats;
import com.sleepycat.je.RunRecoveryException;
import com.sleepycat.je.TransactionConfig;
import com.sleepycat.je.dbi.CursorImpl;
import com.sleepycat.je.dbi.DatabaseId;
import com.sleepycat.je.dbi.DatabaseImpl;
import com.sleepycat.je.dbi.EnvironmentImpl;
import com.sleepycat.je.dbi.MemoryBudget;
import com.sleepycat.je.log.LogManager;
import com.sleepycat.je.log.LogReadable;
import com.sleepycat.je.log.LogUtils;
import com.sleepycat.je.log.LogWritable;
import com.sleepycat.je.log.entry.LNLogEntry;
import com.sleepycat.je.recovery.RecoveryManager;
import com.sleepycat.je.tree.LN;
import com.sleepycat.je.tree.TreeLocation;
import com.sleepycat.je.utilint.DbLsn;
import com.sleepycat.je.utilint.Tracer;
/**
* A Txn is one that's created by a call to Environment.txnBegin. This class
* must support multithreaded use.
*/
public class Txn extends Locker implements LogWritable, LogReadable {
public static final byte TXN_NOSYNC = 0;
public static final byte TXN_WRITE_NOSYNC = 1;
public static final byte TXN_SYNC = 2;
private static final String DEBUG_NAME =
Txn.class.getName();
private byte txnState;
/*
* Cursors opened under this txn. Implemented as a simple linked list to
* conserve on memory.
*/
private CursorImpl cursorSet;
/* txnState bits. */
private static final byte USABLE = 0;
private static final byte CLOSED = 1;
private static final byte ONLY_ABORTABLE = 2;
private static final byte STATE_BITS = 3;
/* Set if prepare() has been called on this transaction. */
private static final byte IS_PREPARED = 4;
/* Set if xa_end(TMSUSPEND) has been called on this transaction. */
private static final byte XA_SUSPENDED = 8;
/*
* A Txn can be used by multiple threads. Modification to the read and
* write lock collections is done by synchronizing on the txn.
*/
private Set readLocks;
private Map writeInfo; // key=nodeid, data = WriteLockInfo
private final int READ_LOCK_OVERHEAD = MemoryBudget.HASHSET_ENTRY_OVERHEAD;
private final int WRITE_LOCK_OVERHEAD =
MemoryBudget.HASHMAP_ENTRY_OVERHEAD + MemoryBudget.LONG_OVERHEAD;
/*
* We have to keep a set of DatabaseCleanupInfo objects so after
* commit or abort of Environment.truncateDatabase() or
* Environment.removeDatabase(), we can appropriately purge the
* unneeded MapLN and DatabaseImpl.
* Synchronize access to this set on this object.
*/
private Set deletedDatabases;
/*
* We need a map of the latest databaseImpl objects to drive the undo
* during an abort, because it's too hard to look up the database object in
* the mapping tree. (The normal code paths want to take locks, add
* cursors, etc.
*/
private Map undoDatabases;
/* Last LSN logged for this transaction. */
private long lastLoggedLsn = DbLsn.NULL_LSN;
/*
* First LSN logged for this transaction -- used for keeping track of the
* first active LSN point, for checkpointing. This field is not persistent.
*/
private long firstLoggedLsn = DbLsn.NULL_LSN;
/* Whether to flush and sync on commit by default. */
private byte defaultFlushSyncBehavior;
/* Whether to use Serializable isolation (prevent phantoms). */
private boolean serializableIsolation;
/* Whether to use Read-Committed isolation. */
private boolean readCommittedIsolation;
/*
* In-memory size, in bytes. A Txn tracks the memory needed for itself and
* the readlock, writeInfo, undoDatabases, and deletedDatabases
* collections, including the cost of each collection entry. However, the
* actual Lock object memory cost is maintained within the Lock class.
*/
private int inMemorySize;
/*
* accumluted memory budget delta. Once this exceeds
* ACCUMULATED_LIMIT we inform the MemoryBudget that a change
* has occurred.
*/
private int accumulatedDelta = 0;
/*
* Max allowable accumulation of memory budget changes before MemoryBudget
* should be updated. This allows for consolidating multiple calls to
* updateXXXMemoryBudget() into one call. Not declared final so that unit
* tests can modify this. See SR 12273.
*/
public static int ACCUMULATED_LIMIT = 10000;
/**
* Create a transaction from Environment.txnBegin.
*/
public Txn(EnvironmentImpl envImpl, TransactionConfig config)
throws DatabaseException {
/*
* Initialize using the config but don't hold a reference to it, since
* it has not been cloned.
*/
super(envImpl, config.getReadUncommitted(), config.getNoWait());
init(envImpl, config);
}
public Txn(EnvironmentImpl envImpl, TransactionConfig config, long id)
throws DatabaseException {
/*
* Initialize using the config but don't hold a reference to it, since
* it has not been cloned.
*/
super(envImpl, config.getReadUncommitted(), config.getNoWait());
init(envImpl, config);
this.id = id;
}
private void init(EnvironmentImpl envImpl, TransactionConfig config)
throws DatabaseException {
serializableIsolation = config.getSerializableIsolation();
readCommittedIsolation = config.getReadCommitted();
/*
* Figure out what we should do on commit. TransactionConfig could be
* set with conflicting values; take the most stringent ones first.
* All environment level defaults were applied by the caller.
*
* ConfigSync ConfigWriteNoSync ConfigNoSync default
* 0 0 0 sync
* 0 0 1 nosync
* 0 1 0 write nosync
* 0 1 1 write nosync
* 1 0 0 sync
* 1 0 1 sync
* 1 1 0 sync
* 1 1 1 sync
*/
if (config.getSync()) {
defaultFlushSyncBehavior = TXN_SYNC;
} else if (config.getWriteNoSync()) {
defaultFlushSyncBehavior = TXN_WRITE_NOSYNC;
} else if (config.getNoSync()) {
defaultFlushSyncBehavior = TXN_NOSYNC;
} else {
defaultFlushSyncBehavior = TXN_SYNC;
}
lastLoggedLsn = DbLsn.NULL_LSN;
firstLoggedLsn = DbLsn.NULL_LSN;
txnState = USABLE;
/*
* Note: readLocks, writeInfo, undoDatabases, deleteDatabases are
* initialized lazily in order to conserve memory. WriteInfo and
* undoDatabases are treated as a package deal, because they are both
* only needed if a transaction does writes.
*
* When a lock is added to this transaction, we add the collection
* entry overhead to the memory cost, but don't add the lock
* itself. That's taken care of by the Lock class.
*/
updateMemoryUsage(MemoryBudget.TXN_OVERHEAD);
this.envImpl.getTxnManager().registerTxn(this);
}
/**
* Constructor for reading from log.
*/
public Txn() {
lastLoggedLsn = DbLsn.NULL_LSN;
}
/**
* UserTxns get a new unique id for each instance.
*/
protected long generateId(TxnManager txnManager) {
return txnManager.incTxnId();
}
/**
* Access to last LSN.
*/
long getLastLsn() {
return lastLoggedLsn;
}
public void setPrepared(boolean prepared) {
if (prepared) {
txnState |= IS_PREPARED;
} else {
txnState &= ~IS_PREPARED;
}
}
public void setSuspended(boolean suspended) {
if (suspended) {
txnState |= XA_SUSPENDED;
} else {
txnState &= ~XA_SUSPENDED;
}
}
public boolean isSuspended() {
return (txnState & XA_SUSPENDED) != 0;
}
/**
* Gets a lock on this nodeId and, if it is a write lock, saves an abort
* LSN. Caller will set the abortLsn later, after the write lock has been
* obtained.
*
* @see Locker#lockInternal
* @Override
*/
LockResult lockInternal(long nodeId,
LockType lockType,
boolean noWait,
DatabaseImpl database)
throws DatabaseException {
long timeout = 0;
boolean useNoWait = noWait || defaultNoWait;
synchronized (this) {
checkState(false);
if (!useNoWait) {
timeout = lockTimeOutMillis;
}
}
/* Ask for the lock. */
LockGrantType grant = lockManager.lock
(nodeId, this, lockType, timeout, useNoWait, database);
WriteLockInfo info = null;
if (writeInfo != null) {
if (grant != LockGrantType.DENIED && lockType.isWriteLock()) {
synchronized (this) {
info = (WriteLockInfo) writeInfo.get(new Long(nodeId));
/* Save the latest version of this database for undoing. */
undoDatabases.put(database.getId(), database);
}
}
}
return new LockResult(grant, info);
}
public int prepare(Xid xid)
throws DatabaseException {
if ((txnState & IS_PREPARED) != 0) {
throw new DatabaseException
("prepare() has already been called for Transaction " +
id + ".");
}
synchronized (this) {
checkState(false);
if (checkCursorsForClose()) {
throw new DatabaseException
("Transaction " + id +
" prepare failed because there were open cursors.");
}
TxnPrepare prepareRecord =
new TxnPrepare(id, xid); /* Flush required. */
LogManager logManager = envImpl.getLogManager();
logManager.logForceFlush(prepareRecord, true); // sync required
}
setPrepared(true);
return XAResource.XA_OK;
}
public void commit(Xid xid)
throws DatabaseException {
commit(TXN_SYNC);
envImpl.getTxnManager().unRegisterXATxn(xid, true);
return;
}
public void abort(Xid xid)
throws DatabaseException {
abort(true);
envImpl.getTxnManager().unRegisterXATxn(xid, false);
return;
}
/**
* Call commit() with the default sync configuration property.
*/
public long commit()
throws DatabaseException {
return commit(defaultFlushSyncBehavior);
}
/**
* Commit this transaction
* 1. Releases read locks
* 2. Writes a txn commit record into the log
* 3. Flushes the log to disk.
* 4. Add deleted LN info to IN compressor queue
* 5. Release all write locks
*
* If any step of this fails, we must convert this transaction to an abort.
*/
public long commit(byte flushSyncBehavior)
throws DatabaseException {
try {
long commitLsn = DbLsn.NULL_LSN;
synchronized (this) {
checkState(false);
if (checkCursorsForClose()) {
throw new DatabaseException
("Transaction " + id +
" commit failed because there were open cursors.");
}
/* Transfer handle locks to their owning handles. */
if (handleLockToHandleMap != null) {
Iterator handleLockIter =
handleLockToHandleMap.entrySet().iterator();
while (handleLockIter.hasNext()){
Map.Entry entry = (Map.Entry) handleLockIter.next();
transferHandleLockToHandleSet((Long) entry.getKey(),
(Set) entry.getValue());
}
}
LogManager logManager = envImpl.getLogManager();
/*
* Release all read locks, clear lock collection. Optimize for
* the case where there are no read locks.
*/
int numReadLocks = clearReadLocks();
/*
* Log the commit if we ever held any write locks. Note that
* with dbhandle write locks, we may have held the write lock
* but then had it transferred away.
*/
int numWriteLocks = 0;
if (writeInfo != null) {
numWriteLocks = writeInfo.size();
TxnCommit commitRecord =
new TxnCommit(id, lastLoggedLsn);
if (flushSyncBehavior == TXN_SYNC) {
/* Flush and sync required. */
commitLsn = logManager.
logForceFlush(commitRecord, true);
} else if (flushSyncBehavior == TXN_WRITE_NOSYNC) {
/* Flush but no sync required. */
commitLsn = logManager.
logForceFlush(commitRecord, false);
} else {
/* No flush, no sync required. */
commitLsn = logManager.log(commitRecord);
}
/*
* Set database state for deletes before releasing any
* write locks.
*/
setDeletedDatabaseState(true);
/*
* Used to prevent double counting abortLNS if there is
* more then one node with the same abortLSN in this txn.
* Two nodes with the same abortLSN occur when a deleted
* slot is reused in the same txn.
*/
Set alreadyCountedLsnSet = new HashSet();
/* Release all write locks, clear lock collection. */
Iterator iter = writeInfo.values().iterator();
while (iter.hasNext()) {
WriteLockInfo info = (WriteLockInfo) iter.next();
lockManager.release(info.lock, this);
/*
* Count the abortLSN as obsolete. Do not count if a
* slot with a deleted LN was reused
* (abortKnownDeleted), to avoid double counting.
*/
if (info.abortLsn != DbLsn.NULL_LSN &&
!info.abortKnownDeleted) {
Long longLsn = new Long(info.abortLsn);
if (!alreadyCountedLsnSet.contains(longLsn)) {
logManager.countObsoleteNode
(info.abortLsn, null);
alreadyCountedLsnSet.add(longLsn);
}
}
}
writeInfo = null;
/* Unload delete info, but don't wake up the compressor. */
if ((deleteInfo != null) && deleteInfo.size() > 0) {
envImpl.addToCompressorQueue(deleteInfo.values(),
false); // don't wakeup
deleteInfo.clear();
}
}
traceCommit(numWriteLocks, numReadLocks);
}
/*
* Purge any databaseImpls not needed as a result of the commit.
* Be sure to do this outside the synchronization block, to avoid
* conflict w/checkpointer.
*/
cleanupDatabaseImpls(true);
/*
* Unregister this txn. Be sure to do this outside the
* synchronization block, to avoid conflict w/checkpointer.
*/
close(true);
return commitLsn;
} catch (RunRecoveryException e) {
/* May have received a thread interrupt. */
throw e;
} catch (Throwable t) {
try {
/*
* If the exception thrown is a DatabaseException it indicates
* that the write() call hit an IOException, probably out of
* disk space, and attempted to rewrite all commit records as
* abort records. Since the abort records are already
* rewritten (or at least attempted to be rewritten), there is
* no reason to have abort attempt to write an abort record
* again. See [11271].
*/
abortInternal(flushSyncBehavior == TXN_SYNC,
!(t instanceof DatabaseException));
Tracer.trace(envImpl, "Txn", "commit",
"Commit of transaction " + id + " failed", t);
} catch (Throwable abortT2) {
throw new DatabaseException
("Failed while attempting to commit transaction " +
id +
". The attempt to abort and clean up also failed. " +
"The original exception seen from commit = " +
t.getMessage() +
" The exception from the cleanup = " +
abortT2.getMessage(),
t);
}
/* Now throw an exception that shows the commit problem. */
throw new DatabaseException
("Failed while attempting to commit transaction " + id +
", aborted instead. Original exception = " +
t.getMessage(), t);
}
}
/**
* Abort this transaction. Steps are:
* 1. Release LN read locks.
* 2. Write a txn abort entry to the log. This is only for log
* file cleaning optimization and there's no need to guarantee a
* flush to disk.
* 3. Find the last LN log entry written for this txn, and use that
* to traverse the log looking for nodes to undo. For each node,
* use the same undo logic as recovery to rollback the transaction. Note
* that we walk the log in order to undo in reverse order of the
* actual operations. For example, suppose the txn did this:
* delete K1/D1 (in LN 10)
* create K1/D1 (in LN 20)
* If we process LN10 before LN 20, we'd inadvertently create a
* duplicate tree of "K1", which would be fatal for the mapping tree.
* 4. Release the write lock for this LN.
*/
public long abort(boolean forceFlush)
throws DatabaseException {
return abortInternal(forceFlush, true);
}
private long abortInternal(boolean forceFlush, boolean writeAbortRecord)
throws DatabaseException {
try {
int numReadLocks;
int numWriteLocks;
long abortLsn;
synchronized (this) {
checkState(true);
/* Log the abort. */
TxnAbort abortRecord = new TxnAbort(id, lastLoggedLsn);
abortLsn = DbLsn.NULL_LSN;
if (writeInfo != null) {
if (writeAbortRecord) {
if (forceFlush) {
abortLsn = envImpl.getLogManager().
logForceFlush(abortRecord, true);
} else {
abortLsn =
envImpl.getLogManager().log(abortRecord);
}
}
}
/* Undo the changes. */
undo();
/*
* Release all read locks after the undo (since the undo may
* need to read in mapLNs).
*/
numReadLocks = (readLocks == null) ? 0 : clearReadLocks();
/*
* Set database state for deletes before releasing any write
* locks.
*/
setDeletedDatabaseState(false);
/* Throw away write lock collection. */
numWriteLocks = (writeInfo == null) ? 0 : clearWriteLocks();
/*
* Let the delete related info (binreferences and dbs) get
* gc'ed. Don't explicitly iterate and clear -- that's far less
* efficient, gives GC wrong input.
*/
deleteInfo = null;
}
/*
* Purge any databaseImpls not needed as a result of the abort. Be
* sure to do this outside the synchronization block, to avoid
* conflict w/checkpointer.
*/
cleanupDatabaseImpls(false);
synchronized (this) {
boolean openCursors = checkCursorsForClose();
Tracer.trace(Level.FINE,
envImpl,
"Abort:id = " + id +
" numWriteLocks= " + numWriteLocks +
" numReadLocks= " + numReadLocks +
" openCursors= " + openCursors);
if (openCursors) {
throw new DatabaseException
("Transaction " + id +
" detected open cursors while aborting");
}
/* Unload any db handles protected by this txn. */
if (handleToHandleLockMap != null) {
Iterator handleIter =
handleToHandleLockMap.keySet().iterator();
while (handleIter.hasNext()){
Database handle = (Database) handleIter.next();
DbInternal.dbInvalidate(handle);
}
}
return abortLsn;
}
} finally {
/*
* Unregister this txn, must be done outside synchronization block
* to avoid conflict w/checkpointer.
*/
close(false);
}
}
/**
* Rollback the changes to this txn's write locked nodes.
*/
private void undo()
throws DatabaseException {
Long nodeId = null;
long undoLsn = lastLoggedLsn;
LogManager logManager = envImpl.getLogManager();
try {
Set alreadyUndone = new HashSet();
TreeLocation location = new TreeLocation();
while (undoLsn != DbLsn.NULL_LSN) {
LNLogEntry undoEntry =
(LNLogEntry) logManager.getLogEntry(undoLsn);
LN undoLN = undoEntry.getLN();
nodeId = new Long(undoLN.getNodeId());
/*
* Only process this if this is the first time we've seen this
* node. All log entries for a given node have the same
* abortLsn, so we don't need to undo it multiple times.
*/
if (!alreadyUndone.contains(nodeId)) {
alreadyUndone.add(nodeId);
DatabaseId dbId = undoEntry.getDbId();
DatabaseImpl db = (DatabaseImpl) undoDatabases.get(dbId);
undoLN.postFetchInit(db, undoLsn);
long abortLsn = undoEntry.getAbortLsn();
boolean abortKnownDeleted =
undoEntry.getAbortKnownDeleted();
try {
RecoveryManager.undo(Level.FINER,
db,
location,
undoLN,
undoEntry.getKey(),
undoEntry.getDupKey(),
undoLsn,
abortLsn,
abortKnownDeleted,
null, false);
} finally {
if (location.bin != null) {
location.bin.releaseLatchIfOwner();
}
}
/*
* The LN undone is counted as obsolete if it was not
* deleted.
*/
if (!undoLN.isDeleted()) {
logManager.countObsoleteNode(undoLsn, null);
}
}
/* Move on to the previous log entry for this txn. */
undoLsn = undoEntry.getUserTxn().getLastLsn();
}
} catch (RuntimeException e) {
throw new DatabaseException("Txn undo for node=" + nodeId +
" LSN=" +
DbLsn.getNoFormatString(undoLsn), e);
} catch (DatabaseException e) {
Tracer.trace(envImpl, "Txn", "undo",
"for node=" + nodeId + " LSN=" +
DbLsn.getNoFormatString(undoLsn), e);
throw e;
}
}
private int clearWriteLocks()
throws DatabaseException {
int numWriteLocks = writeInfo.size();
/* Release all write locks, clear lock collection. */
Iterator iter = writeInfo.values().iterator();
while (iter.hasNext()) {
WriteLockInfo info = (WriteLockInfo) iter.next();
lockManager.release(info.lock, this);
}
writeInfo = null;
return numWriteLocks;
}
private int clearReadLocks()
throws DatabaseException {
int numReadLocks = 0;
if (readLocks != null) {
numReadLocks = readLocks.size();
Iterator iter = readLocks.iterator();
while (iter.hasNext()) {
Lock rLock = (Lock) iter.next();
lockManager.release(rLock, this);
}
readLocks = null;
}
return numReadLocks;
}
/**
* Called by the recovery manager when logging a transaction aware object.
* This method is synchronized by the caller, by being called within the
* log latch. Record the last LSN for this transaction, to create the
* transaction chain, and also record the LSN in the write info for abort
* logic.
*/
public void addLogInfo(long lastLsn)
throws DatabaseException {
/* Save the last LSN for maintaining the transaction LSN chain. */
lastLoggedLsn = lastLsn;
/* Save handle to LSN for aborts. */
synchronized (this) {
/*
* If this is the first LSN, save it for calculating the first LSN
* of any active txn, for checkpointing.
*/
if (firstLoggedLsn == DbLsn.NULL_LSN) {
firstLoggedLsn = lastLsn;
}
}
}
/**
* @return first logged LSN, to aid recovery rollback.
*/
long getFirstActiveLsn()
throws DatabaseException {
synchronized (this) {
return firstLoggedLsn;
}
}
/**
* @param dbImpl databaseImpl to remove
* @param deleteAtCommit true if this databaseImpl should be cleaned on
* commit, false if it should be cleaned on abort.
* @param mb environment memory budget.
*/
public void markDeleteAtTxnEnd(DatabaseImpl dbImpl, boolean deleteAtCommit)
throws DatabaseException {
synchronized (this) {
int delta = 0;
if (deletedDatabases == null) {
deletedDatabases = new HashSet();
delta += MemoryBudget.HASHSET_OVERHEAD;
}
deletedDatabases.add(new DatabaseCleanupInfo(dbImpl,
deleteAtCommit));
delta += MemoryBudget.HASHSET_ENTRY_OVERHEAD +
MemoryBudget.OBJECT_OVERHEAD;
updateMemoryUsage(delta);
}
}
/*
* Leftover databaseImpls that are a by-product of database operations like
* removeDatabase(), truncateDatabase() will be deleted after the write
* locks are released. However, do set the database state appropriately
* before the locks are released.
*/
private void setDeletedDatabaseState(boolean isCommit)
throws DatabaseException {
if (deletedDatabases != null) {
Iterator iter = deletedDatabases.iterator();
while (iter.hasNext()) {
DatabaseCleanupInfo info = (DatabaseCleanupInfo) iter.next();
if (info.deleteAtCommit == isCommit) {
info.dbImpl.startDeleteProcessing();
}
}
}
}
/**
* Cleanup leftover databaseImpls that are a by-product of database
* operations like removeDatabase(), truncateDatabase().
*
* This method must be called outside the synchronization on this txn,
* because it calls deleteAndReleaseINs, which gets the TxnManager's
* allTxns latch. The checkpointer also gets the allTxns latch, and within
* that latch, needs to synchronize on individual txns, so we must avoid a
* latching hiearchy conflict.
*/
private void cleanupDatabaseImpls(boolean isCommit)
throws DatabaseException {
if (deletedDatabases != null) {
/* Make a copy of the deleted databases while synchronized. */
DatabaseCleanupInfo[] infoArray;
synchronized (this) {
infoArray = new DatabaseCleanupInfo[deletedDatabases.size()];
deletedDatabases.toArray(infoArray);
}
for (int i = 0; i < infoArray.length; i += 1) {
DatabaseCleanupInfo info = infoArray[i];
if (info.deleteAtCommit == isCommit) {
info.dbImpl.releaseDeletedINs();
}
}
deletedDatabases = null;
}
}
/**
* Add lock to the appropriate queue.
*/
void addLock(Long nodeId,
Lock lock,
LockType type,
LockGrantType grantStatus)
throws DatabaseException {
synchronized (this) {
int delta = 0;
if (type.isWriteLock()) {
if (writeInfo == null) {
writeInfo = new HashMap();
undoDatabases = new HashMap();
delta += MemoryBudget.TWOHASHMAPS_OVERHEAD;
}
writeInfo.put(nodeId,
new WriteLockInfo(lock));
delta += WRITE_LOCK_OVERHEAD;
if ((grantStatus == LockGrantType.PROMOTION) ||
(grantStatus == LockGrantType.WAIT_PROMOTION)) {
readLocks.remove(lock);
delta -= READ_LOCK_OVERHEAD;
}
updateMemoryUsage(delta);
} else {
addReadLock(lock);
}
}
}
private void addReadLock(Lock lock) {
int delta = 0;
if (readLocks == null) {
readLocks = new HashSet();
delta = MemoryBudget.HASHSET_OVERHEAD;
}
readLocks.add(lock);
delta += READ_LOCK_OVERHEAD;
updateMemoryUsage(delta);
}
/**
* Remove the lock from the set owned by this transaction. If specified to
* LockManager.release, the lock manager will call this when its releasing
* a lock. Usually done because the transaction doesn't need to really keep
* the lock, i.e for a deleted record.
*/
void removeLock(long nodeId, Lock lock)
throws DatabaseException {
/*
* We could optimize by passing the lock type so we know which
* collection to look in. Be careful of demoted locks, which have
* shifted collection.
*
* Don't bother updating memory utilization here -- we'll update at
* transaction end.
*/
synchronized (this) {
if ((readLocks != null) &&
readLocks.remove(lock)) {
updateMemoryUsage(0 - READ_LOCK_OVERHEAD);
} else if ((writeInfo != null) &&
(writeInfo.remove(new Long(nodeId)) != null)) {
updateMemoryUsage(0 - WRITE_LOCK_OVERHEAD);
}
}
}
/**
* A lock is being demoted. Move it from the write collection into the read
* collection.
*/
void moveWriteToReadLock(long nodeId, Lock lock) {
boolean found = false;
synchronized (this) {
if ((writeInfo != null) &&
(writeInfo.remove(new Long(nodeId)) != null)) {
found = true;
updateMemoryUsage(0 - WRITE_LOCK_OVERHEAD);
}
assert found : "Couldn't find lock for Node " + nodeId +
" in writeInfo Map.";
addReadLock(lock);
}
}
private void updateMemoryUsage(int delta) {
inMemorySize += delta;
accumulatedDelta += delta;
if (accumulatedDelta > ACCUMULATED_LIMIT ||
accumulatedDelta < -ACCUMULATED_LIMIT) {
envImpl.getMemoryBudget().updateMiscMemoryUsage(accumulatedDelta);
accumulatedDelta = 0;
}
}
int getAccumulatedDelta() {
return accumulatedDelta;
}
/**
* @return true if this transaction created this node. We know that this
* is true if the node is write locked and has a null abort LSN.
*/
public boolean createdNode(long nodeId)
throws DatabaseException {
boolean created = false;
synchronized (this) {
if (writeInfo != null) {
WriteLockInfo info = (WriteLockInfo)
writeInfo.get(new Long(nodeId));
if (info != null) {
created = info.createdThisTxn;
}
}
}
return created;
}
/**
* @return the abortLsn for this node.
*/
public long getAbortLsn(long nodeId)
throws DatabaseException {
WriteLockInfo info = null;
synchronized (this) {
if (writeInfo != null) {
info = (WriteLockInfo) writeInfo.get(new Long(nodeId));
}
}
if (info == null) {
return DbLsn.NULL_LSN;
} else {
return info.abortLsn;
}
}
/**
* @return the WriteLockInfo for this node.
*/
public WriteLockInfo getWriteLockInfo(long nodeId)
throws DatabaseException {
WriteLockInfo info = WriteLockInfo.basicWriteLockInfo;
synchronized (this) {
if (writeInfo != null) {
info = (WriteLockInfo) writeInfo.get(new Long(nodeId));
}
}
return info;
}
/**
* Is always transactional.
*/
public boolean isTransactional() {
return true;
}
/**
* Is serializable isolation if so configured.
*/
public boolean isSerializableIsolation() {
return serializableIsolation;
}
/**
* Is read-committed isolation if so configured.
*/
public boolean isReadCommittedIsolation() {
return readCommittedIsolation;
}
/**
* This is a transactional locker.
*/
public Txn getTxnLocker() {
return this;
}
/**
* Returns 'this', since this locker holds no non-transactional locks.
*/
public Locker newNonTxnLocker()
throws DatabaseException {
return this;
}
/**
* This locker holds no non-transactional locks.
*/
public void releaseNonTxnLocks()
throws DatabaseException {
}
/**
* Created transactions do nothing at the end of the operation.
*/
public void operationEnd()
throws DatabaseException {
}
/**
* Created transactions do nothing at the end of the operation.
*/
public void operationEnd(boolean operationOK)
throws DatabaseException {
}
/**
* Created transactions don't transfer locks until commit.
*/
public void setHandleLockOwner(boolean ignore /*operationOK*/,
Database dbHandle,
boolean dbIsClosing)
throws DatabaseException {
if (dbIsClosing) {
/*
* If the Database handle is closing, take it out of the both the
* handle lock map and the handle map. We don't need to do any
* transfers at commit time, and we don't need to do any
* invalidations at abort time.
*/
Long handleLockId = (Long) handleToHandleLockMap.get(dbHandle);
if (handleLockId != null) {
Set dbHandleSet = (Set)
handleLockToHandleMap.get(handleLockId);
boolean removed = dbHandleSet.remove(dbHandle);
assert removed :
"Can't find " + dbHandle + " from dbHandleSet";
if (dbHandleSet.size() == 0) {
Object foo = handleLockToHandleMap.remove(handleLockId);
assert (foo != null) :
"Can't find " + handleLockId +
" from handleLockIdtoHandleMap.";
}
}
unregisterHandle(dbHandle);
} else {
/*
* If the db is still open, make sure the db knows this txn is its
* handle lock protector and that this txn knows it owns this db
* handle.
*/
if (dbHandle != null) {
DbInternal.dbSetHandleLocker(dbHandle, this);
}
}
}
/**
* Cursors operating under this transaction are added to the collection.
*/
public void registerCursor(CursorImpl cursor)
throws DatabaseException {
synchronized(this) {
/* Add to the head of the list. */
cursor.setLockerNext(cursorSet);
if (cursorSet != null) {
cursorSet.setLockerPrev(cursor);
}
cursorSet = cursor;
}
}
/**
* Remove a cursor from the collection.
*/
public void unRegisterCursor(CursorImpl cursor)
throws DatabaseException {
synchronized (this) {
CursorImpl prev = cursor.getLockerPrev();
CursorImpl next = cursor.getLockerNext();
if (prev == null) {
cursorSet = next;
} else {
prev.setLockerNext(next);
}
if (next != null) {
next.setLockerPrev(prev);
}
cursor.setLockerPrev(null);
cursor.setLockerNext(null);
}
}
/**
* @return true if this txn is willing to give up the handle lock to
* another txn before this txn ends.
*/
public boolean isHandleLockTransferrable() {
return false;
}
/**
* Check if all cursors associated with the txn are closed. If not, those
* open cursors will be forcibly closed.
* @return true if open cursors exist
*/
private boolean checkCursorsForClose()
throws DatabaseException {
CursorImpl c = cursorSet;
while (c != null) {
if (!c.isClosed()) {
return true;
}
c = c.getLockerNext();
}
return false;
}
/**
* stats
*/
public LockStats collectStats(LockStats stats)
throws DatabaseException {
synchronized (this) {
int nReadLocks = (readLocks == null) ? 0 : readLocks.size();
stats.setNReadLocks(stats.getNReadLocks() + nReadLocks);
int nWriteLocks = (writeInfo == null) ? 0 : writeInfo.size();
stats.setNWriteLocks(stats.getNWriteLocks() + nWriteLocks);
}
return stats;
}
/**
* Set the state of a transaction to ONLY_ABORTABLE.
*/
public void setOnlyAbortable() {
txnState &= ~STATE_BITS;
txnState |= ONLY_ABORTABLE;
}
/**
* Get the state of a transaction's ONLY_ABORTABLE.
*/
public boolean getOnlyAbortable() {
return (txnState & ONLY_ABORTABLE) != 0;
}
/**
* Throw an exception if the transaction is not open.
*
* If calledByAbort is true, it means we're being called
* from abort().
*
* Caller must invoke with "this" synchronized.
*/
protected void checkState(boolean calledByAbort)
throws DatabaseException {
boolean ok = false;
boolean onlyAbortable = false;
byte state = (byte) (txnState & STATE_BITS);
ok = (state == USABLE);
onlyAbortable = (state == ONLY_ABORTABLE);
if (!calledByAbort && onlyAbortable) {
/*
* It's ok for FindBugs to whine about id not being synchronized.
*/
throw new DatabaseException
("Transaction " + id + " must be aborted.");
}
if (ok ||
(calledByAbort && onlyAbortable)) {
return;
}
/*
* It's ok for FindBugs to whine about id not being synchronized.
*/
throw new DatabaseException
("Transaction " + id + " has been closed.");
}
/**
*/
private void close(boolean isCommit)
throws DatabaseException {
synchronized (this) {
txnState &= ~STATE_BITS;
txnState |= CLOSED;
}
/*
* UnregisterTxn must be called outside the synchronization on this
* txn, because it gets the TxnManager's allTxns latch. The
* checkpointer also gets the allTxns latch, and within that latch,
* needs to synchronize on individual txns, so we must avoid a latching
* hiearchy conflict.
*/
envImpl.getTxnManager().unRegisterTxn(this, isCommit);
}
/*
* Log support
*/
/**
* @see LogWritable#getLogSize
*/
public int getLogSize() {
/* id and lastLoggedLsn */
return LogUtils.LONG_BYTES + LogUtils.LONG_BYTES;
}
/**
* @see LogWritable#writeToLog
*/
/*
* It's ok for FindBugs to whine about id not being synchronized.
*/
public void writeToLog(ByteBuffer logBuffer) {
LogUtils.writeLong(logBuffer, id);
LogUtils.writeLong(logBuffer, lastLoggedLsn);
}
/**
* @see LogReadable#readFromLog
*
* It's ok for FindBugs to whine about id not being synchronized.
*/
public void readFromLog(ByteBuffer logBuffer, byte entryTypeVersion) {
id = LogUtils.readLong(logBuffer);
lastLoggedLsn = LogUtils.readLong(logBuffer);
}
/**
* @see LogReadable#dumpLog
*/
public void dumpLog(StringBuffer sb, boolean verbose) {
sb.append("<txn id=\"");
sb.append(super.toString());
sb.append("\">");
sb.append(DbLsn.toString(lastLoggedLsn));
sb.append("</txn>");
}
/**
* @see LogReadable#getTransactionId
*/
public long getTransactionId() {
return getId();
}
/**
* @see LogReadable#logEntryIsTransactional
*/
public boolean logEntryIsTransactional() {
return true;
}
/**
* Transfer a single handle lock to the set of corresponding handles at
* commit time.
*/
private void transferHandleLockToHandleSet(Long handleLockId,
Set dbHandleSet)
throws DatabaseException {
/* Create a set of destination transactions */
int numHandles = dbHandleSet.size();
Database [] dbHandles = new Database[numHandles];
dbHandles = (Database []) dbHandleSet.toArray(dbHandles);
Locker [] destTxns = new Locker[numHandles];
for (int i = 0; i < numHandles; i++) {
destTxns[i] = new BasicLocker(envImpl);
}
/* Move this lock to the destination txns. */
long nodeId = handleLockId.longValue();
lockManager.transferMultiple(nodeId, this, destTxns);
for (int i = 0; i < numHandles; i++) {
/*
* Make this handle and its handle protector txn remember each
* other.
*/
destTxns[i].addToHandleMaps(handleLockId, dbHandles[i]);
DbInternal.dbSetHandleLocker(dbHandles[i], destTxns[i]);
}
}
/**
* Send trace messages to the java.util.logger. Don't rely on the logger
* alone to conditionalize whether we send this message, we don't even want
* to construct the message if the level is not enabled. The string
* construction can be numerous enough to show up on a performance profile.
*/
private void traceCommit(int numWriteLocks, int numReadLocks) {
Logger logger = envImpl.getLogger();
if (logger.isLoggable(Level.FINE)) {
StringBuffer sb = new StringBuffer();
sb.append(" Commit:id = ").append(id);
sb.append(" numWriteLocks=").append(numWriteLocks);
sb.append(" numReadLocks = ").append(numReadLocks);
Tracer.trace(Level.FINE, envImpl, sb.toString());
}
}
int getInMemorySize() {
return inMemorySize;
}
/**
* Store information about a DatabaseImpl that will have to be
* purged at transaction commit or abort. This handles cleanup after
* operations like Environment.truncateDatabase,
* Environment.removeDatabase. Cleanup like this is done outside the
* usual transaction commit or node undo processing, because
* the mapping tree is always AutoTxn'ed to avoid deadlock and is
* essentially non-transactional
*/
private static class DatabaseCleanupInfo {
DatabaseImpl dbImpl;
/* if true, clean on commit. If false, clean on abort. */
boolean deleteAtCommit;
DatabaseCleanupInfo(DatabaseImpl dbImpl,
boolean deleteAtCommit) {
this.dbImpl = dbImpl;
this.deleteAtCommit = deleteAtCommit;
}
}
}