BUG#28073: Infinite loop in lock queue.

In a certain code path the NDBD could loop infinitely in the lock queue.

storage/ndb/src/kernel/blocks/dbacc/DbaccMain.cpp

@@ -1321,7 +1321,7 @@ Dbacc::startNext(Signal* signal, OperationrecPtr lastOp)
    * We must check if there are many transactions in parallel queue...
    */
   OperationrecPtr tmp;
-  tmp.i = loPtr.p->nextParallelQue;
+  tmp= loPtr;
   while (tmp.i != RNIL)
   {
     ptrCheckGuard(tmp, coprecsize, operationrec);      
@@ -1333,6 +1333,7 @@ Dbacc::startNext(Signal* signal, OperationrecPtr lastOp)
        */
       return;
     }
+    tmp.i = tmp.p->nextParallelQue;
   }
   
 upgrade:

storage/ndb/test/include/HugoOperations.hpp

@@ -27,7 +27,8 @@ public:
 		 const NdbDictionary::Index* idx = 0);
 
   ~HugoOperations();
-  int startTransaction(Ndb*);
+  int startTransaction(Ndb*, const NdbDictionary::Table *table= 0,
+                       const char  *keyData= 0, Uint32 keyLen= 0);
   int setTransaction(NdbTransaction*,bool not_null_ok= false);
   int closeTransaction(Ndb*);
   NdbTransaction* getTransaction();

storage/ndb/test/ndbapi/testBasic.cpp

@@ -1272,6 +1272,74 @@ runBug25090(NDBT_Context* ctx, NDBT_Step* step){
   return NDBT_OK;
 }
 
+int
+runBug28073(NDBT_Context *ctx, NDBT_Step* step)
+{
+  int result = NDBT_OK;
+  const NdbDictionary::Table *table= ctx->getTab();
+  HugoOperations hugoOp1(*table);
+  HugoOperations hugoOp2(*table);
+  Ndb* pNdb = GETNDB(step);
+  int loops = ctx->getNumLoops();
+  bool inserted= false;
+
+  while (loops--)
+  {
+    if (!inserted)
+    {
+      CHECK(hugoOp1.startTransaction(pNdb) == 0);
+      CHECK(hugoOp1.pkInsertRecord(pNdb, 1, 1) == 0);
+      CHECK(hugoOp1.execute_Commit(pNdb) == 0);
+      CHECK(hugoOp1.closeTransaction(pNdb) == 0);
+      inserted= 1;
+    }
+
+    // Use TC hint to hit the same node in both transactions.
+    Uint32 key_val= 0;
+    const char *key= (const char *)(&key_val);
+    CHECK(hugoOp1.startTransaction(pNdb, table, key, 4) == 0);
+    CHECK(hugoOp2.startTransaction(pNdb, table, key, 4) == 0);
+
+    // First take 2*read lock on the tuple in transaction 1.
+    for (Uint32 i= 0; i < 2; i++)
+    {
+      CHECK(hugoOp1.pkReadRecord(pNdb, 1, 1, NdbOperation::LM_Read) == 0);
+      CHECK(hugoOp1.pkReadRecord(pNdb, 1, 1, NdbOperation::LM_Read) == 0);
+    }
+    CHECK(hugoOp1.execute_NoCommit(pNdb) == 0);
+
+    // Now send ops in two transactions, one batch.
+    // First 2*read in transaction 2.
+    for (Uint32 i= 0; i < 2; i++)
+    {
+      CHECK(hugoOp2.pkReadRecord(pNdb, 1, 1, NdbOperation::LM_Read) == 0);
+      CHECK(hugoOp2.pkReadRecord(pNdb, 1, 1, NdbOperation::LM_Read) == 0);
+    }
+    CHECK(hugoOp2.execute_async_prepare(pNdb, NdbTransaction::NoCommit) == 0);
+
+    // Second op an update in transaction 1.
+    CHECK(hugoOp1.pkUpdateRecord(pNdb, 1, 1) == 0);
+    CHECK(hugoOp1.execute_async_prepare(pNdb, NdbTransaction::Commit) == 0);
+
+    // Transaction 1 will now hang waiting on transaction 2 to commit before it
+    // can upgrade its read lock to a write lock.
+    // With the bug, we get a node failure due to watchdog timeout here.
+    CHECK(hugoOp2.wait_async(pNdb) == 0);
+
+    // Now commit transaction 2, we should see transaction 1 finish with the
+    // update.
+    CHECK(hugoOp2.execute_async_prepare(pNdb, NdbTransaction::Commit) == 0);
+    CHECK(hugoOp2.wait_async(pNdb) == 0);
+    // No error check, as transaction 1 may have terminated already.
+    hugoOp1.wait_async(pNdb);
+
+    CHECK(hugoOp1.closeTransaction(pNdb) == 0);
+    CHECK(hugoOp2.closeTransaction(pNdb) == 0);
+  }
+
+  return result;
+}
+
 NDBT_TESTSUITE(testBasic);
 TESTCASE("PkInsert", 
 	 "Verify that we can insert and delete from this table using PK"
@@ -1542,6 +1610,10 @@ TESTCASE("Bug25090",
 	 "Verify what happens when we fill the db" ){
   STEP(runBug25090);
 }
+TESTCASE("Bug28073", 
+	 "Infinite loop in lock queue" ){
+  STEP(runBug28073);
+}
 NDBT_TESTSUITE_END(testBasic);
 
 #if 0

storage/ndb/test/run-test/daily-basic-tests.txt

@@ -235,6 +235,10 @@ max-time: 500
 cmd: testBasic
 args: -n Bug25090 T1
 
+max-time: 500
+cmd: testBasic
+args: -n Bug28073
+
 max-time: 500
 cmd: testIndex
 args: -n Bug25059 -r 3000 T1

storage/ndb/test/src/HugoOperations.cpp

@@ -15,13 +15,15 @@
 
 #include <HugoOperations.hpp>
 
-int HugoOperations::startTransaction(Ndb* pNdb){
+int HugoOperations::startTransaction(Ndb* pNdb,
+                                     const NdbDictionary::Table *table,
+                                     const char  *keyData, Uint32 keyLen){
   
   if (pTrans != NULL){
     ndbout << "HugoOperations::startTransaction, pTrans != NULL" << endl;
     return NDBT_FAILED;
   }
-  pTrans = pNdb->startTransaction();
+  pTrans = pNdb->startTransaction(table, keyData, keyLen);
   if (pTrans == NULL) {
     const NdbError err = pNdb->getNdbError();
     ERR(err);