better determination of a blocking transaction deadlock detection

h2/src/main/org/h2/mvstore/tx/Transaction.java

@@ -175,7 +175,7 @@ public class Transaction {
      * @param status to be set
      * @return transaction state as it was before status change
      */
-    long setStatus(int status) {
+    private long setStatus(int status) {
         while (true) {
             long currentState = statusAndLogId.get();
             long logId = getLogId(currentState);
@@ -486,8 +486,10 @@ public class Transaction {
                             "Transaction %d attempts to update map <%s> entry with key <%s>"
                                     + " modified by transaction %s%n",
                             transactionId, blockingMap.getName(), blockingKey, toWaitFor));
-                    throw DataUtils.newIllegalStateException(DataUtils.ERROR_TRANSACTIONS_DEADLOCK,
-                            details.toString());
+                    if (isDeadlocked(toWaitFor)) {
+                        throw DataUtils.newIllegalStateException(DataUtils.ERROR_TRANSACTIONS_DEADLOCK,
+                                details.toString());
+                    }
                 }
             }
         }
@@ -515,8 +517,10 @@ public class Transaction {
 
     private synchronized boolean waitForThisToEnd(int millis) {
         long until = System.currentTimeMillis() + millis;
+        long state;
         int status;
-        while((status = getStatus()) != STATUS_CLOSED && status != STATUS_ROLLING_BACK) {
+        while((status = getStatus(state = statusAndLogId.get())) != STATUS_CLOSED
+                && status != STATUS_ROLLED_BACK && !hasRollback(state)) {
             long dur = until - System.currentTimeMillis();
             if(dur <= 0) {
                 return false;

h2/src/main/org/h2/mvstore/tx/TxDecisionMaker.java

@@ -49,7 +49,7 @@ abstract class TxDecisionMaker extends MVMap.DecisionMaker<VersionedValue> {
             // because a tree root has definitely been changed.
             logIt(existingValue.value == null ? null : VersionedValue.getInstance(existingValue.value));
             decision = MVMap.Decision.PUT;
-        } else if (fetchTransaction(blockingId) != null) {
+        } else if (getBlockingTransaction() != null) {
             // this entry comes from a different transaction, and this
             // transaction is not committed yet
             // should wait on blockingTransaction that was determined earlier
@@ -106,11 +106,17 @@ abstract class TxDecisionMaker extends MVMap.DecisionMaker<VersionedValue> {
     }
 
     final boolean isCommitted(int transactionId) {
-        return transaction.store.committingTransactions.get().get(transactionId);
-    }
-
-    final Transaction fetchTransaction(int transactionId) {
-        return (blockingTransaction = transaction.store.getTransaction(transactionId));
+        Transaction blockingTx;
+        boolean result;
+        do {
+            blockingTx = transaction.store.getTransaction(transactionId);
+            result = transaction.store.committingTransactions.get().get(transactionId);
+        } while (blockingTx != transaction.store.getTransaction(transactionId));
+
+        if (!result) {
+            blockingTransaction = blockingTx;
+        }
+        return result;
     }
 
     final MVMap.Decision setDecision(MVMap.Decision d) {
@@ -167,7 +173,7 @@ abstract class TxDecisionMaker extends MVMap.DecisionMaker<VersionedValue> {
                     // and therefore will be committed soon
                     logIt(null);
                     return setDecision(MVMap.Decision.PUT);
-                } else if (fetchTransaction(blockingId) != null) {
+                } else if (getBlockingTransaction() != null) {
                     // this entry comes from a different transaction, and this
                     // transaction is not committed yet
                     // should wait on blockingTransaction that was determined