From dcb1155481a5c28bfc40ea14ccae450c2e78e17e Mon Sep 17 00:00:00 2001
From: Steven Li <stevenli@taosdata.com>
Date: Fri, 8 May 2020 17:40:43 -0700
Subject: [PATCH] Discovered TD-256 with params: -p -d -t 10 -s 20

---
 tests/pytest/crash_gen.py | 50 ++++++++++++++++++++++++++++++---------
 1 file changed, 39 insertions(+), 11 deletions(-)

diff --git a/tests/pytest/crash_gen.py b/tests/pytest/crash_gen.py
index 431de7c56a..6a724709e2 100755
--- a/tests/pytest/crash_gen.py
+++ b/tests/pytest/crash_gen.py
@@ -136,11 +136,17 @@ class WorkerThread:
         self._stepGate.set() # wake up!        
         time.sleep(0) # let the released thread run a bit
 
-    def execSql(self, sql):
+    def execSql(self, sql): # not "execute", since we are out side the DB context
         if ( gConfig.per_thread_db_connection ):
-            return self._dbConn.execSql(sql)            
+            return self._dbConn.execute(sql)            
         else:
-            return self._tc.getDbState.getDbConn().execSql(sql)
+            return self._tc.getDbState.getDbConn().execute(sql)
+
+    def querySql(self, sql): # not "execute", since we are out side the DB context
+        if ( gConfig.per_thread_db_connection ):
+            return self._dbConn.query(sql)            
+        else:
+            return self._tc.getDbState.getDbConn().query(sql)
                   
 class ThreadCoordinator:
     def __init__(self, pool, wd: WorkDispatcher, dbState):
@@ -380,10 +386,16 @@ class DbConn:
         self._tdSql.close()
         self.isOpen = False
 
-    def execSql(self, sql): 
+    def execute(self, sql): 
+        if ( not self.isOpen ):
+            raise RuntimeError("Cannot execute database commands until connection is open")
+        return self._tdSql.execute(sql)
+
+    def query(self, sql) -> int :  # return number of rows retrieved
         if ( not self.isOpen ):
             raise RuntimeError("Cannot query database until connection is open")
-        return self._tdSql.execute(sql)
+        return self._tdSql.query(sql)
+
 
 # State of the database as we believe it to be
 class DbState():
@@ -441,27 +453,36 @@ class DbState():
         return "table_{}".format(tblNum)
 
     def execSql(self, sql): # using the main DB connection
-        return self._dbConn.execSql(sql)
+        return self._dbConn.execute(sql)
 
     def cleanUp(self):
         self._dbConn.close()      
 
     def getTasksAtState(self):
+        tasks = []
+        tasks.append(ReadFixedDataTask(self)) # always
         if ( self._state == self.STATE_EMPTY ):
-            return [CreateDbTask(self), CreateFixedTableTask(self)]
+            tasks.append(CreateDbTask(self))
+            tasks.append(CreateFixedTableTask(self))
         elif ( self._state == self.STATE_DB_ONLY ):
-            return [DropDbTask(self), CreateFixedTableTask(self), AddFixedDataTask(self)]
+            tasks.append(DropDbTask(self))
+            tasks.append(CreateFixedTableTask(self))
+            tasks.append(AddFixedDataTask(self))
         elif ( self._state == self.STATE_TABLE_ONLY ):
-            return [DropFixedTableTask(self), AddFixedDataTask(self)]
+            tasks.append(DropFixedTableTask(self))
+            tasks.append(AddFixedDataTask(self))
         elif ( self._state == self.STATE_HAS_DATA ) : # same as above. TODO: adjust
-            return [DropFixedTableTask(self), AddFixedDataTask(self)]
+            tasks.append(DropFixedTableTask(self))
+            tasks.append(AddFixedDataTask(self))
         else:
             raise RuntimeError("Unexpected DbState state: {}".format(self._state))
+        return tasks
 
     def transition(self, tasks):
         if ( len(tasks) == 0 ): # before 1st step, or otherwise empty
             return # do nothing
         if ( self._state == self.STATE_EMPTY ):
+            # self.assertNoSuccess(tasks, ReadFixedDataTask) # some read may be successful, since we might be creating a table
             if ( self.hasSuccess(tasks, CreateDbTask) ):
                 self.assertAtMostOneSuccess(tasks, CreateDbTask) # param is class
                 self._state = self.STATE_DB_ONLY
@@ -504,7 +525,7 @@ class DbState():
             else: # did not drop table, did not insert data, that is impossible
                 raise RuntimeError("Unexpected no-success scenarios")
 
-        elif ( self._state == self.STATE_TABLE_ONLY ): # Same as above, TODO: adjust
+        elif ( self._state == self.STATE_HAS_DATA ): # Same as above, TODO: adjust
             if ( self.hasSuccess(tasks, DropFixedTableTask) ):
                 self.assertAtMostOneSuccess(tasks, DropFixedTableTask)
                 self._state = self.STATE_DB_ONLY
@@ -589,6 +610,7 @@ class Task():
         self._workerThread = None 
         self._err = None
         self._curStep = None
+        self._numRows = None # Number of rows affected
 
         # Assign an incremental task serial number        
         self._taskNum = self.allocTaskNum()
@@ -653,6 +675,12 @@ class CreateFixedTableTask(Task):
         tblName = self._dbState.getFixedTableName()        
         wt.execSql("create table db.{} (ts timestamp, speed int)".format(tblName))
 
+class ReadFixedDataTask(Task):
+    def _executeInternal(self, te: TaskExecutor, wt: WorkerThread):
+        tblName = self._dbState.getFixedTableName()        
+        self._numRows = wt.querySql("select * from db.{}".format(tblName)) # save the result for later
+        # tdSql.query(" cars where tbname in ('carzero', 'carone')")
+
 class DropTableTask(Task):
     def _executeInternal(self, te: TaskExecutor, wt: WorkerThread):
         tableName = self._dbState.getTableNameToDelete()