ascherbakoff commented on code in PR #4540: URL: https://github.com/apache/ignite-3/pull/4540#discussion_r1814629644
########## modules/transactions/src/main/java/org/apache/ignite/internal/tx/impl/HeapLockManager.java: ########## @@ -328,10 +349,359 @@ 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; + }); + } + /** - * A lock state. + * Create lock exception with given parameters. + * + * @param locker Locker. + * @param holder Lock holder. + * @return Lock exception. */ - public class LockState { + 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 + ']'); + } + + /** + * 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. + */ + 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 requested 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 IgniteStripedReadWriteLock stripedLock = new IgniteStripedReadWriteLock(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 { + lock = slockOwners.get(txId); + + if (lock != null) { + return lock; + } + + IgniteBiTuple<Lock, CompletableFuture<Lock>> tuple = slockWaiters.get(txId); + + if (tuple != null) { + return tuple.get1(); + } + } finally { + stripedLock.readLock(idx).unlock(); + } + + return null; + } + + @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 { + // IX-locks can't be modified under the striped write lock. + if (!ixlockOwners.isEmpty()) { + if (ixlockOwners.containsKey(txId)) { + 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)); + // TODO: https://issues.apache.org/jira/browse/IGNITE-21153 + if (res.isCompletedExceptionally()) { + return failedFuture(abandonedLockException(txId, holderTx)); + } + + // Validate reordering with IX locks. + for (Lock lock : ixlockOwners.values()) { + // Allow only high priority transactions to wait. + if (TxIdPriorityComparator.INSTANCE.compare(lock.txId(), txId) < 0) { Review Comment: 🆗 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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