Revert "Merge pull request #1046 from drrtuy/MCOL-3769"

This has an uninit'd var warning from the compiler.  It fixes one test
and breaks 2 others in test001.

This reverts commit cf668897ef, reversing
changes made to 25084d0020.

dbcon/mysql/ha_mcs_opt_rewrites.cpp

@@ -18,7 +18,7 @@
 
 // Search simplify_joins() function in the server's code for detail
 COND *
-simplify_joins_cs(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top,
+simplify_joins_(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top,
                bool in_sj)
 {
   TABLE_LIST *table;
@@ -26,7 +26,7 @@ simplify_joins_cs(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top
   TABLE_LIST *prev_table= 0;
   List_iterator<TABLE_LIST> li(*join_list);
   bool straight_join= MY_TEST(join->select_options & SELECT_STRAIGHT_JOIN);
-  DBUG_ENTER("simplify_joins_cs");
+  DBUG_ENTER("simplify_joins");
 
   /* 
     Try to simplify join operations from join_list.
@@ -54,7 +54,7 @@ simplify_joins_cs(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top
            the outer join is converted to an inner join and
            the corresponding on expression is added to E. 
 	*/ 
-        expr= simplify_joins_cs(join, &nested_join->join_list,
+        expr= simplify_joins_(join, &nested_join->join_list,
                              expr, FALSE, in_sj || table->sj_on_expr);
 
         if (!table->prep_on_expr || expr != table->on_expr)
@@ -67,7 +67,7 @@ simplify_joins_cs(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top
       }
       nested_join->used_tables= (table_map) 0;
       nested_join->not_null_tables=(table_map) 0;
-      conds= simplify_joins_cs(join, &nested_join->join_list, conds, top, 
+      conds= simplify_joins_(join, &nested_join->join_list, conds, top, 
                             in_sj || table->sj_on_expr);
       used_tables= nested_join->used_tables;
       not_null_tables= nested_join->not_null_tables;  

dbcon/mysql/ha_mcs_opt_rewrites.h

@@ -20,6 +20,7 @@
 
 #include "idb_mysql.h"
 
-COND *simplify_joins_cs(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top, bool in_sj);
+COND *simplify_joins_(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top, bool in_sj);
+
 #endif
 

dbcon/mysql/ha_mcs_pushdown.cpp

@@ -21,6 +21,7 @@
 
 void check_walk(const Item* item, void* arg);
 
+
 void disable_indices_for_CEJ(THD *thd_)
 {
     TABLE_LIST* global_list;
@@ -41,7 +42,7 @@ void disable_indices_for_CEJ(THD *thd_)
     }
 }
 
-bool optimize_unflattened_subqueries_cs(SELECT_LEX *select_lex)
+bool optimize_unflattened_subqueries_(SELECT_LEX *select_lex)
 {
     bool result = false;
     TABLE_LIST *tbl;
@@ -51,7 +52,7 @@ bool optimize_unflattened_subqueries_cs(SELECT_LEX *select_lex)
         if (tbl->is_view_or_derived())
         {
             SELECT_LEX *dsl = tbl->derived->first_select();
-            result = optimize_unflattened_subqueries_cs(dsl);
+            result = optimize_unflattened_subqueries_(dsl);
         }
     }
 
@@ -807,6 +808,7 @@ create_columnstore_select_handler(THD* thd, SELECT_LEX* select_lex)
         return handler;
     }
 
+    bool unsupported_feature = false;
     // Select_handler use the short-cut that effectively disables
     // INSERT..SELECT, LDI, SELECT..INTO OUTFILE
     if ((thd->lex)->sql_command == SQLCOM_INSERT_SELECT
@@ -814,41 +816,28 @@ create_columnstore_select_handler(THD* thd, SELECT_LEX* select_lex)
         || (thd->lex)->exchange)
         
     {
-        return handler;
+        unsupported_feature = true;
     }
 
-    // We apply dedicated rewrites from MDB here so the data structures
-    // becomes dirty and CS has to raise an error in case of any problem.
-    bool unsupported_feature = false;
-    logging::Message::Args args;
     JOIN *join= select_lex->join;
+    // Next block tries to execute the query using SH very early to fallback
+    // if execution fails.
+    if (!unsupported_feature)
     {
         disable_indices_for_CEJ(thd);
 
         if (select_lex->handle_derived(thd->lex, DT_MERGE))
         {
-            // set to true b/c of an error in handle_derived
+            // early quit b/c of the error in handle_derived
-            unsupported_feature = true;
+            return handler;
-            args.add("in handle_derived()");
-        }
-
-        COND *conds;
-        if (!unsupported_feature)
-        {
-            conds = simplify_joins_cs(join, select_lex->join_list,
-                join->conds, TRUE, FALSE);
         }
 
+        COND *conds = simplify_joins_(join, select_lex->join_list, join->conds, TRUE, FALSE);
         // MCOL-3747 IN-TO-EXISTS rewrite inside MDB didn't add
         // an equi-JOIN condition.
-        if (!unsupported_feature
+        optimize_unflattened_subqueries_(select_lex);
-            && optimize_unflattened_subqueries_cs(select_lex))
-        {
-            unsupported_feature = true;
-            args.add("in optimize_unflattened_subqueries_cs()");
-        }
     
-        if (!unsupported_feature && conds)
+        if (conds)
         {
 #ifdef DEBUG_WALK_COND
             conds->traverse_cond(cal_impl_if::debug_walk, NULL, Item::POSTFIX);
@@ -856,6 +845,15 @@ create_columnstore_select_handler(THD* thd, SELECT_LEX* select_lex)
             join->conds = conds;
         }
 
+        // Impossible HAVING or WHERE
+        // TODO replace with function call
+        if (unsupported_feature
+           || select_lex->having_value == Item::COND_FALSE
+            || select_lex->cond_value == Item::COND_FALSE )
+        {
+            unsupported_feature = true;
+            restore_optimizer_flags(thd);
+        }
     }
 
     // Restore back the saved group_list
@@ -876,7 +874,6 @@ create_columnstore_select_handler(THD* thd, SELECT_LEX* select_lex)
             item_check(item, &unsupported_feature);
             if (unsupported_feature)
             {
-                args.add("in item_check()");
                 break;
             }
         }
@@ -893,20 +890,13 @@ create_columnstore_select_handler(THD* thd, SELECT_LEX* select_lex)
         {
             rc= ha_cs_impl_pushdown_init(&mhi, handler->table);
         }
-        unsupported_feature = (rc) ? true : unsupported_feature;
 
         // Return SH even if init fails b/c CS changed SELECT_LEX structures
-        // with simplify_joins_cs and other rewrites()
+        // with simplify_joins_()
-        // the handler will return error on next_row()
+        if (rc)
+            unsupported_feature = true;
         return handler;
     }
-    else
-    {
-        std::string emsg=
-            logging::IDBErrorInfo::instance()->errorMsg(ER_INTERNAL_ERROR, args);
-        thd->raise_error_printf(ER_INTERNAL_ERROR, emsg.c_str());
-    }
-    restore_optimizer_flags(thd);
 
     return NULL;
 }