chore(plugin): move projection processing into a separate part.

dbcon/mysql/ha_mcs_execplan.cpp

@@ -7674,57 +7674,18 @@ void buildInToExistsFilter(gp_walk_info& gwi, SELECT_LEX& select_lex)
   }
 }
 
-/*@brief  Translates SELECT_LEX into CSEP                  */
+
+/*@brief  Process SELECT part of a query or sub-query      */
 /***********************************************************
  * DESCRIPTION:
- *  This function takes SELECT_LEX and tries to produce
+ *  Processes SELECT part of a query or sub-query
- *  a corresponding CSEP out of it. It is made of parts that
- *  process parts of the query, e.g. FROM, WHERE, SELECT,
- *  HAVING, GROUP BY, ORDER BY. FROM, WHERE, LIMIT are processed
- *  by corresponding methods. CS calls getSelectPlan()
- *  recursively to process subqueries.
- * ARGS
- *  isUnion if true CS processes UNION unit now
- *  isSelectHandlerTop removes offset at the top of SH query.
  * RETURNS
  *  error id as an int
  ***********************************************************/
-int getSelectPlan(gp_walk_info& gwi, SELECT_LEX& select_lex, SCSEP& csep, bool isUnion,
+ int processSelect(SELECT_LEX& select_lex, gp_walk_info& gwi, SCSEP& csep, 
-                  bool isSelectHandlerTop, bool isSelectLexUnit, const std::vector<COND*>& condStack)
+   vector<Item_field*>& funcFieldVec,
+   CalpontSelectExecutionPlan::SelectList& selectSubList)
  {
-#ifdef DEBUG_WALK_COND
-  cerr << "getSelectPlan()" << endl;
-#endif
-  int rc = 0;
-  // rollup is currently not supported
-  bool withRollup = select_lex.olap == ROLLUP_TYPE;
-
-  setExecutionParams(gwi, csep);
-
-  gwi.subSelectType = csep->subType();
-  uint32_t sessionID = csep->sessionID();
-  gwi.sessionid = sessionID;
-  boost::shared_ptr<CalpontSystemCatalog> csc = CalpontSystemCatalog::makeCalpontSystemCatalog(sessionID);
-  csc->identity(CalpontSystemCatalog::FE);
-  csep->timeZone(gwi.timeZone);
-  gwi.csc = csc;
-
-  CalpontSelectExecutionPlan::SelectList derivedTbList;
-  // @bug 1796. Remember table order on the FROM list.
-  gwi.clauseType = FROM;
-  if ((rc = processFrom(isUnion, select_lex, gwi, csep, isSelectHandlerTop, isSelectLexUnit)))
-  {
-    return rc;
-  }
-
-  gwi.clauseType = WHERE;
-  if ((rc = processWhere(select_lex, gwi, csep, condStack)))
-  {
-    return rc;
-  }
-
-  gwi.clauseType = SELECT;
-  SELECT_LEX* oldSelectLex = gwi.select_lex;  // XXX: SZ: should it be restored in case of error return?
     gwi.select_lex = &select_lex;
  #ifdef DEBUG_WALK_COND
    {
@@ -7770,7 +7731,6 @@ int getSelectPlan(gp_walk_info& gwi, SELECT_LEX& select_lex, SCSEP& csep, bool i
    // populate returnedcolumnlist and columnmap
    List_iterator_fast<Item> it(select_lex.item_list);
    Item* item;
-  vector<Item_field*> funcFieldVec;
  
    // empty rcWorkStack and ptWorkStack. They should all be empty by now.
    clearStacks(gwi, false, true);
@@ -7785,7 +7745,6 @@ int getSelectPlan(gp_walk_info& gwi, SELECT_LEX& select_lex, SCSEP& csep, bool i
        scalar->returnedColPos(gwi.additionalRetCols.size());
    }
  
-  CalpontSelectExecutionPlan::SelectList selectSubList;
  
    while ((item = it++))
    {
@@ -8220,6 +8179,67 @@ int getSelectPlan(gp_walk_info& gwi, SELECT_LEX& select_lex, SCSEP& csep, bool i
        }
      }
    }
+   return 0;
+ }
+
+/*@brief  Translates SELECT_LEX into CSEP                  */
+/***********************************************************
+ * DESCRIPTION:
+ *  This function takes SELECT_LEX and tries to produce
+ *  a corresponding CSEP out of it. It is made of parts that
+ *  process parts of the query, e.g. FROM, WHERE, SELECT,
+ *  HAVING, GROUP BY, ORDER BY. FROM, WHERE, LIMIT are processed
+ *  by corresponding methods. CS calls getSelectPlan()
+ *  recursively to process subqueries.
+ * ARGS
+ *  isUnion if true CS processes UNION unit now
+ *  isSelectHandlerTop removes offset at the top of SH query.
+ * RETURNS
+ *  error id as an int
+ ***********************************************************/
+int getSelectPlan(gp_walk_info& gwi, SELECT_LEX& select_lex, SCSEP& csep, bool isUnion,
+                  bool isSelectHandlerTop, bool isSelectLexUnit, const std::vector<COND*>& condStack)
+{
+#ifdef DEBUG_WALK_COND
+  cerr << "getSelectPlan()" << endl;
+#endif
+  int rc = 0;
+  // rollup is currently not supported
+  bool withRollup = select_lex.olap == ROLLUP_TYPE;
+
+  setExecutionParams(gwi, csep);
+
+  gwi.subSelectType = csep->subType();
+  uint32_t sessionID = csep->sessionID();
+  gwi.sessionid = sessionID;
+  boost::shared_ptr<CalpontSystemCatalog> csc = CalpontSystemCatalog::makeCalpontSystemCatalog(sessionID);
+  csc->identity(CalpontSystemCatalog::FE);
+  csep->timeZone(gwi.timeZone);
+  gwi.csc = csc;
+
+  CalpontSelectExecutionPlan::SelectList derivedTbList;
+  // @bug 1796. Remember table order on the FROM list.
+  gwi.clauseType = FROM;
+  if ((rc = processFrom(isUnion, select_lex, gwi, csep, isSelectHandlerTop, isSelectLexUnit)))
+  {
+    return rc;
+  }
+
+  gwi.clauseType = WHERE;
+  if ((rc = processWhere(select_lex, gwi, csep, condStack)))
+  {
+    return rc;
+  }
+
+  gwi.clauseType = SELECT;
+  SELECT_LEX* originalSelectLex = gwi.select_lex;  // XXX: SZ: should it be restored in case of error return?
+  vector<Item_field*> funcFieldVec;
+  CalpontSelectExecutionPlan::SelectList selectSubList;
+
+  if ((rc = processSelect(select_lex, gwi, csep, funcFieldVec, selectSubList)))
+  {
+    return rc;
+  }
 
   // Having clause handling
   gwi.clauseType = HAVING;
@@ -8994,7 +9014,7 @@ int getSelectPlan(gp_walk_info& gwi, SELECT_LEX& select_lex, SCSEP& csep, bool i
   for (uint32_t i = 0; i < gwi.localCols.size(); i++)
     gwi.localCols[i]->sequence(i);
 
-  gwi.select_lex = oldSelectLex;
+  gwi.select_lex = originalSelectLex;
   // append additionalRetCols to returnedCols
   gwi.returnedCols.insert(gwi.returnedCols.begin(), gwi.additionalRetCols.begin(),
                           gwi.additionalRetCols.end());