denis-chudov commented on code in PR #4540:
URL: https://github.com/apache/ignite-3/pull/4540#discussion_r1813045997
##########
modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/HeapLockManager.java:
##########
@@ -328,10 +357,331 @@ private LockState adjustLockState(LockState state,
LockState v) {
}
}
+ private void track(UUID txId, Releasable val) {
+ txMap.compute(txId, (k, v) -> {
+ if (v == null) {
+ v = new ConcurrentLinkedQueue<>();
+ }
+
+ v.add(val);
+
+ return v;
+ });
+ }
+
+ /**
+ * Create lock exception with given parameters.
+ *
+ * @param locker Locker.
+ * @param holder Lock holder.
+ * @return Lock exception.
+ */
+ private static LockException lockException(UUID locker, UUID holder) {
+ return new LockException(ACQUIRE_LOCK_ERR,
+ "Failed to acquire a lock due to a possible deadlock [locker="
+ locker + ", holder=" + holder + ']');
+ }
+
/**
- * A lock state.
+ * Create lock exception when lock holder is believed to be missing.
+ *
+ * @param locker Locker.
+ * @param holder Lock holder.
+ * @return Lock exception.
+ */
+ private static LockException abandonedLockException(UUID locker, UUID
holder) {
+ return new LockException(ACQUIRE_LOCK_ERR,
+ "Failed to acquire an abandoned lock due to a possible
deadlock [locker=" + locker + ", holder=" + holder + ']');
+ }
+
+ /**
+ * Common interface for releasing transaction locks.
*/
- public class LockState {
+ interface Releasable {
+ /**
+ * Tries to release a lock.
+ *
+ * @param txId Tx id.
+ * @return {@code True} if lock state requires cleanup after release.
+ */
+ boolean tryRelease(UUID txId);
+
+ /**
+ * Gets associated lock key.
+ *
+ * @return Lock key.
+ */
+ LockKey key();
+
+ /**
+ * Returns the lock which is held by given tx.
+ *
+ * @param txId Tx id.
+ * @return The lock or null if no lock exist.
+ */
+ @Nullable Lock lock(UUID txId);
+
+ /**
+ * Returns lock type.
+ *
+ * @return The type.
+ */
+ boolean coarse();
+ }
+
+ /**
+ * Coarse lock.
+ */
+ public class CoarseLockState implements Releasable {
+ private final StripedCompositeReadWriteLock stripedLock = new
StripedCompositeReadWriteLock(CONCURRENCY);
+
+ private final ConcurrentHashMap<UUID, Lock> ixlockOwners = new
ConcurrentHashMap<>();
+ private final Map<UUID, IgniteBiTuple<Lock, CompletableFuture<Lock>>>
slockWaiters = new HashMap<>();
+ private final ConcurrentHashMap<UUID, Lock> slockOwners = new
ConcurrentHashMap<>();
+
+ private final LockKey lockKey;
+
+ CoarseLockState(LockKey lockKey) {
+ this.lockKey = lockKey;
+ }
+
+ @Override
+ public boolean tryRelease(UUID txId) {
+ Lock lock = lock(txId);
+
+ release(lock);
+
+ return false;
+ }
+
+ @Override
+ public LockKey key() {
+ return lockKey;
+ }
+
+ @Override
+ public Lock lock(UUID txId) {
+ Lock lock = ixlockOwners.get(txId);
+
+ if (lock != null) {
+ return lock;
+ }
+
+ int idx = Math.floorMod(spread(txId.hashCode()), CONCURRENCY);
+
+ stripedLock.readLock(idx).lock();
+
+ try {
+ return slockOwners.get(txId);
+ } finally {
+ stripedLock.readLock(idx).unlock();
+ }
+ }
+
+ @Override
+ public boolean coarse() {
+ return true;
+ }
+
+ /**
+ * Acquires a lock.
+ *
+ * @param txId Tx id.
+ * @param lockKey Lock key.
+ * @param lockMode Lock mode.
+ * @return The future.
+ */
+ public CompletableFuture<Lock> acquire(UUID txId, LockKey lockKey,
LockMode lockMode) {
+ switch (lockMode) {
+ case S:
+ stripedLock.writeLock().lock();
+
+ try {
+ if (!ixlockOwners.isEmpty()) {
+ if (ixlockOwners.containsKey(txId)) {
+ // IX-locks can't be modified under the
striped lock.
+ if (ixlockOwners.size() == 1) {
+ // Safe to upgrade.
+ track(txId, this); // Double track.
+ Lock lock = new Lock(lockKey, lockMode,
txId);
+ slockOwners.putIfAbsent(txId, lock);
+ return completedFuture(lock);
+ } else {
+ // Attempt to upgrade to SIX in the
presence of concurrent transactions. Deny lock attempt.
+ for (Lock lock : ixlockOwners.values()) {
+ if (!lock.txId().equals(txId)) {
+ return
failedFuture(lockException(txId, lock.txId()));
+ }
+ }
+ }
+
+ assert false : "Should not reach here";
+ }
+
+ UUID holderTx =
ixlockOwners.keySet().iterator().next();
+ CompletableFuture<Void> res =
fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx));
+ if (res.isCompletedExceptionally()) {
+ return
failedFuture(abandonedLockException(txId, holderTx));
+ }
+
+ track(txId, this);
+
+ CompletableFuture<Lock> fut = new
CompletableFuture<>();
+ IgniteBiTuple<Lock, CompletableFuture<Lock>> prev
= slockWaiters.putIfAbsent(txId,
+ new IgniteBiTuple<>(new Lock(lockKey,
lockMode, txId), fut));
+ return prev == null ? fut : prev.get2();
+ } else {
+ Lock lock = new Lock(lockKey, lockMode, txId);
+ Lock prev = slockOwners.putIfAbsent(txId, lock);
+
+ if (prev == null) {
+ track(txId, this); // Do not track on reenter.
+ }
+
+ return completedFuture(lock);
+ }
+ } finally {
+ stripedLock.writeLock().unlock();
+ }
+
+ case IX:
+ int idx = Math.floorMod(spread(txId.hashCode()),
CONCURRENCY);
+
+ while (true) {
+ // This will prevent IX to block S, giving deadlock
avoidance.
+ boolean locked = stripedLock.readLock(idx).tryLock();
+
+ // Striped lock is held for short time. Can spin wait
here.
+ if (!locked) {
+ Thread.onSpinWait();
+ } else {
+ break;
+ }
+ }
+
+ try {
+ if (!slockOwners.isEmpty()) {
+ if (slockOwners.containsKey(txId)) {
+ // S-locks can't be modified under the striped
lock.
+ if (slockOwners.size() == 1) {
+ // Safe to upgrade.
+ track(txId, this); // Double track.
+ Lock lock = new Lock(lockKey, lockMode,
txId);
+ ixlockOwners.putIfAbsent(txId, lock);
+ return completedFuture(lock);
+ } else {
+ // Attempt to upgrade to SIX in the
presence of concurrent transactions. Deny lock attempt.
+ for (Lock lock : slockOwners.values()) {
+ if (!lock.txId().equals(txId)) {
+ return
failedFuture(lockException(txId, lock.txId()));
+ }
+ }
+ }
+
+ assert false : "Should not reach here";
+ }
+
+ UUID holderTx =
slockOwners.keySet().iterator().next();
+ CompletableFuture<Void> eventResult =
fireEvent(LOCK_CONFLICT, new LockEventParameters(txId, holderTx));
+ if (eventResult.isCompletedExceptionally()) {
+ return
failedFuture(abandonedLockException(txId, holderTx));
+ } else {
+ return failedFuture(lockException(txId,
holderTx)); // IX locks never wait.
+ }
+ } else {
+ Lock lock = new Lock(lockKey, lockMode, txId);
+ Lock prev = ixlockOwners.putIfAbsent(txId, lock);
// Avoid overwrite existing lock.
+
+ if (prev == null) {
+ track(txId, this); // Do not track on reenter.
+ }
+
+ return completedFuture(lock);
+ }
+ } finally {
+ stripedLock.readLock(idx).unlock();
+ }
+
+ default:
+ assert false : "Unsupported coarse lock mode: " + lockMode;
+ }
+
+ return null; // Should not be here.
+ }
+
+ /**
+ * Releases the lock. Should be called from {@link #releaseAll(UUID)}.
+ *
+ * @param lock The lock.
+ */
+ public void release(@Nullable Lock lock) {
+ if (lock == null) {
+ return;
+ }
+
+ switch (lock.lockMode()) {
+ case S:
+ stripedLock.writeLock().lock();
+
+ try {
+ Lock removed = slockOwners.remove(lock.txId());
+
+ assert removed != null : "Attempt to release not
acquired lock: " + lock.txId();
+ } finally {
+ stripedLock.writeLock().unlock();
+ }
+
+ break;
+ case IX:
+ int idx = Math.floorMod(spread(lock.txId().hashCode()),
CONCURRENCY);
+
+ Map<UUID, IgniteBiTuple<Lock, CompletableFuture<Lock>>>
wakeups;
+
+ stripedLock.readLock(idx).lock();
+
+ try {
+ var removed = ixlockOwners.remove(lock.txId());
+
+ assert removed != null : "Attempt to release not
acquired lock: " + lock.txId();
+
+ if (slockWaiters.isEmpty()) {
+ return; // Nothing to do.
+ }
+
+ if (!ixlockOwners.isEmpty()) {
+ assert slockOwners.isEmpty() ||
slockOwners.containsKey(lock.txId());
+
+ return; // Nothing to do.
+ }
+
+ // No race here because no new locks can be acquired
after releaseAll due to 2-phase locking protocol.
+
+ // Promote waiters to owners.
+ wakeups = new HashMap<>(slockWaiters);
+
+ slockWaiters.clear();
+
+ for (IgniteBiTuple<Lock, CompletableFuture<Lock>>
value : wakeups.values()) {
+ slockOwners.put(value.getKey().txId(),
value.getKey());
+ }
+ } finally {
+ stripedLock.readLock(idx).unlock();
+ }
+
+ for (Entry<UUID, IgniteBiTuple<Lock,
CompletableFuture<Lock>>> entry : wakeups.entrySet()) {
+
entry.getValue().get2().complete(entry.getValue().get1());
+ }
+
+ break;
+ default:
+ assert false : "Unsupported coarse unlock mode: " +
lock.lockMode();
Review Comment:
Agree, I should have checked more carefully.
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