manual merge

mysql-test/r/ps.result

@@ -487,3 +487,15 @@ insert into t1 values ('foo');
 prepare stmt FROM 'SELECT char_length (a) FROM t1';
 ERROR 42000: FUNCTION test.char_length does not exist
 drop table t1;
+prepare stmt from "SELECT SQL_CALC_FOUND_ROWS 'foo' UNION SELECT 'bar' LIMIT 0";
+execute stmt;
+foo
+SELECT FOUND_ROWS();
+FOUND_ROWS()
+2
+execute stmt;
+foo
+SELECT FOUND_ROWS();
+FOUND_ROWS()
+2
+deallocate prepare stmt;

mysql-test/t/ps.test

@@ -497,3 +497,13 @@ insert into t1 values ('foo');
 prepare stmt FROM 'SELECT char_length (a) FROM t1'; 
 drop table t1;
 
+#
+# Bug #6089: FOUND_ROWS returns wrong values when no table/view is used 
+#
+
+prepare stmt from "SELECT SQL_CALC_FOUND_ROWS 'foo' UNION SELECT 'bar' LIMIT 0";
+execute stmt;
+SELECT FOUND_ROWS();
+execute stmt;                                                                   
+SELECT FOUND_ROWS();                                                            
+deallocate prepare stmt;

sql/sql_union.cc

@@ -217,8 +217,6 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
 
     thd_arg->lex->current_select= sl;
     set_limit(sl, sl);
-    if (sl->braces)
-      sl->options&= ~OPTION_FOUND_ROWS;
 
     can_skip_order_by= is_union &&
                        (!sl->braces || select_limit_cnt == HA_POS_ERROR);
@@ -342,10 +340,9 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
       if (arena->is_stmt_prepare())
       {
 	/* prepare fake select to initialize it correctly */
-	ulong options_tmp= init_prepare_fake_select_lex(thd);
+	(void) init_prepare_fake_select_lex(thd);
         /*
-          it should be done only once (because item_list builds only onece
-          per statement)
+          Should be done only once (the only item_list per statement).
         */
         DBUG_ASSERT(fake_select_lex->join == 0);
 	if (!(fake_select_lex->join= new JOIN(thd, item_list, thd->options,
@@ -452,21 +449,14 @@ bool st_select_lex_unit::exec()
 	if (select_limit_cnt < sl->select_limit)
 	  select_limit_cnt= HA_POS_ERROR;		// no limit
 
-	/*
-	  When using braces, SQL_CALC_FOUND_ROWS affects the whole query.
-	  We don't calculate found_rows() per union part
-	*/
-	if (select_limit_cnt == HA_POS_ERROR || sl->braces)
-	  sl->options&= ~OPTION_FOUND_ROWS;
-	else 
-	{
-	  /*
-	    We are doing an union without braces.  In this case
-	    SQL_CALC_FOUND_ROWS should be done on all sub parts
-	  */
-	  sl->options|= found_rows_for_union;
-	}
-	sl->join->select_options=sl->options;
+        /*
+          When using braces, SQL_CALC_FOUND_ROWS affects the whole query:
+          we don't calculate found_rows() per union part.
+          Otherwise, SQL_CALC_FOUND_ROWS should be done on all sub parts.
+        */
+        sl->join->select_options= 
+          (select_limit_cnt == HA_POS_ERROR || sl->braces) ?
+          sl->options & ~OPTION_FOUND_ROWS : sl->options | found_rows_for_union;
 	res= sl->join->optimize();
       }
       if (!res)
@@ -498,7 +488,8 @@ bool st_select_lex_unit::exec()
       }
       /* Needed for the following test and for records_at_start in next loop */
       table->file->info(HA_STATUS_VARIABLE);
-      if (found_rows_for_union & sl->options)
+      if (found_rows_for_union && !sl->braces && 
+          select_limit_cnt != HA_POS_ERROR)
       {
 	/*
 	  This is a union without braces. Remember the number of rows that