diff --git a/tests/pytest/crash_gen.py b/tests/pytest/crash_gen.py
index f323611e4d2814421b7858cea32169c813246cd3..d481b135473f0e7ffb687985427dc0e7b41068e6 100755
--- a/tests/pytest/crash_gen.py
+++ b/tests/pytest/crash_gen.py
@@ -658,7 +658,10 @@ class DbConn:
             raise RuntimeError("Cannot query database until connection is open")
         nRows = self.query(sql)
         if nRows != 1:
-            raise RuntimeError("Unexpected result for query: {}, rows = {}".format(sql, nRows))
+            raise taos.error.ProgrammingError(
+                "Unexpected result for query: {}, rows = {}".format(sql, nRows), 
+                (0x991 if nRows==0 else 0x992)
+            )
         if self.getResultRows() != 1 or self.getResultCols() != 1:
             raise RuntimeError("Unexpected result set for query: {}".format(sql))
         return self.getQueryResult()[0][0]
@@ -815,6 +818,7 @@ class MyTDSql:
     def _execInternal(self, sql):
         startTime = time.time() 
         ret = self._cursor.execute(sql)
+        print("\nSQL success: {}".format(sql))
         queryTime =  time.time() - startTime
         # Record the query time
         cls = self.__class__
@@ -1342,13 +1346,17 @@ class Database:
 
         For now we use it to manage state transitions in that database
     '''
+    _clsLock = threading.Lock() # class wide lock
+    _lastInt = 101  # next one is initial integer
+    _lastTick = 0
+    _lastLaggingTick = 0 # lagging tick, for unsequenced insersions
+
     def __init__(self, dbNum: int, dbc: DbConn): # TODO: remove dbc
         self._dbNum = dbNum # we assign a number to databases, for our testing purpose
         self._stateMachine = StateMechine(self)
         self._stateMachine.init(dbc)
 
-        self._lastTick = self.setupLastTick()
-        self._lastInt = 0  # next one is initial integer
+          
         self._lock = threading.RLock()
 
     def getStateMachine(self) -> StateMechine:
@@ -1387,7 +1395,8 @@ class Database:
     # by a factor of 500.
     # TODO: what if it goes beyond 10 years into the future
     # TODO: fix the error as result of above: "tsdb timestamp is out of range"
-    def setupLastTick(self):
+    @classmethod
+    def setupLastTick(cls):
         t1 = datetime.datetime(2020, 6, 1)
         t2 = datetime.datetime.now()
         # maybe a very large number, takes 69 years to exceed Python int range
@@ -1401,14 +1410,22 @@ class Database:
         logger.info("Setting up TICKS to start from: {}".format(t4))
         return t4
 
-    def getNextTick(self):
-        with self._lock:  # prevent duplicate tick
-            if Dice.throw(20) == 0:  # 1 in 20 chance
-                return self._lastTick + datetime.timedelta(0, -100) # Go back in time 100 seconds
+    @classmethod
+    def getNextTick(cls):        
+        with cls._clsLock:  # prevent duplicate tick
+            if cls._lastLaggingTick==0:
+                # 10k at 1/20 chance, should be enough to avoid overlaps
+                cls._lastLaggingTick = cls.setupLastTick() + datetime.timedelta(0, -10000)                 
+            if cls._lastTick==0: # should be quite a bit into the future
+                cls._lastTick = cls.setupLastTick()  
+
+            if Dice.throw(20) == 0:  # 1 in 20 chance, return lagging tick
+                cls._lastLaggingTick += datetime.timedelta(0, 1) # Go back in time 100 seconds
+                return cls._lastLaggingTick 
             else:  # regular
                 # add one second to it
-                self._lastTick += datetime.timedelta(0, 1)
-                return self._lastTick
+                cls._lastTick += datetime.timedelta(0, 1)
+                return cls._lastTick
 
     def getNextInt(self):
         with self._lock:
@@ -2177,6 +2194,7 @@ class TaskAddData(StateTransitionTask):
     def _executeInternal(self, te: TaskExecutor, wt: WorkerThread):
         # ds = self._dbManager # Quite DANGEROUS here, may result in multi-thread client access
         db = self._db
+        dbc = wt.getDbConn()
         tblSeq = list(range(
                 self.LARGE_NUMBER_OF_TABLES if gConfig.larger_data else self.SMALL_NUMBER_OF_TABLES))
         random.shuffle(tblSeq)
@@ -2192,6 +2210,7 @@ class TaskAddData(StateTransitionTask):
            
             for j in range(self.LARGE_NUMBER_OF_RECORDS if gConfig.larger_data else self.SMALL_NUMBER_OF_RECORDS):  # number of records per table
                 nextInt = db.getNextInt()
+                nextTick = db.getNextTick()
                 if gConfig.record_ops:
                     self.prepToRecordOps()
                     self.fAddLogReady.write("Ready to write {} to {}\n".format(nextInt, regTableName))
@@ -2202,8 +2221,8 @@ class TaskAddData(StateTransitionTask):
                     regTableName,
                     # ds.getFixedSuperTableName(),
                     # ds.getNextBinary(), ds.getNextFloat(),
-                    db.getNextTick(), nextInt)
-                self.execWtSql(wt, sql)
+                    nextTick, nextInt)
+                dbc.execute(sql)
                 # Successfully wrote the data into the DB, let's record it
                 # somehow
                 te.recordDataMark(nextInt)
@@ -2213,6 +2232,26 @@ class TaskAddData(StateTransitionTask):
                             nextInt, regTableName))
                     self.fAddLogDone.flush()
                     os.fsync(self.fAddLogDone)
+
+                # Now read it back and verify, we might encounter an error if table is dropped
+                try:
+                    readBack = dbc.queryScalar("SELECT speed from {}.{} WHERE ts= '{}'".
+                        format(db.getName(), regTableName, nextTick))
+                    if readBack != nextInt :
+                        raise taos.error.ProgrammingError(
+                            "Failed to read back same data, wrote: {}, read: {}"
+                            .format(nextInt, readBack), 0x999)
+                except taos.error.ProgrammingError as err:
+                    errno = Helper.convertErrno(err.errno)
+                    if errno in [0x991, 0x992]  : # not a single result
+                        raise taos.error.ProgrammingError(
+                            "Failed to read back same data for tick: {}, wrote: {}, read: {}"
+                            .format(nextTick, nextInt, "Empty Result" if errno==0x991 else "Multiple Result"),
+                            errno)
+                    # Re-throw no matter what
+                    raise
+                
+
             self.activeTable.discard(i)  # not raising an error, unlike remove