Vers cleanups

* Always-false vers_select_conds_t::from_query
* Debug helpers

Closes #684

mysql-test/suite/versioning/r/replace.result

@@ -7,8 +7,7 @@ period for system_time (row_start, row_end)
 ) with system versioning;
 insert t values (1, 2);
 replace t values (1, 3);
-select *, row_end>TIMESTAMP'2038-01-01 00:00:00' as current from t for system_time all
-order by x;
+select *, current_row(row_end) as current from t for system_time all order by x;
 id	x	current
 1	2	0
 1	3	1
@@ -22,8 +21,7 @@ period for system_time (row_start, row_end)
 ) with system versioning;
 insert t values (1, 2);
 replace t values (1, 3);
-select *, row_end>TIMESTAMP'2038-01-01 00:00:00' as current from t for system_time all
-order by x;
+select *, current_row(row_end) as current from t for system_time all order by x;
 id	x	current
 1	2	0
 1	3	1

mysql-test/suite/versioning/t/replace.test

@@ -12,8 +12,7 @@ eval create table t (
 
 insert t values (1, 2);
 replace t values (1, 3);
-select *, row_end>TIMESTAMP'2038-01-01 00:00:00' as current from t for system_time all
-order by x;
+select *, current_row(row_end) as current from t for system_time all order by x;
 drop table t;
 
 --replace_result $sys_datatype_expl SYS_DATATYPE
@@ -27,8 +26,7 @@ eval create table t (
 
 insert t values (1, 2);
 replace t values (1, 3);
-select *, row_end>TIMESTAMP'2038-01-01 00:00:00' as current from t for system_time all
-order by x;
+select *, current_row(row_end) as current from t for system_time all order by x;
 drop table t;
 
 --source suite/versioning/common_finish.inc

sql/sql_select.cc

@@ -678,7 +678,6 @@ bool vers_select_conds_t::init_from_sysvar(THD *thd)
   vers_asof_timestamp_t &in= thd->variables.vers_asof_timestamp;
   type= (vers_system_time_t) in.type;
   start.unit= VERS_TIMESTAMP;
-  from_query= false;
   if (type != SYSTEM_TIME_UNSPECIFIED && type != SYSTEM_TIME_ALL)
   {
     DBUG_ASSERT(type == SYSTEM_TIME_AS_OF);
@@ -741,7 +740,7 @@ int SELECT_LEX::vers_setup_conds(THD *thd, TABLE_LIST *tables)
     {
       if (table->table && table->table->versioned())
         versioned_tables++;
-      else if (table->vers_conditions.user_defined() &&
+      else if (table->vers_conditions.is_set() &&
               (table->is_non_derived() || !table->vers_conditions.used))
       {
         my_error(ER_VERS_NOT_VERSIONED, MYF(0), table->alias.str);

sql/sql_yacc.yy

@@ -11788,9 +11788,10 @@ table_primary_ident:
                                                          pop_index_hints(),
                                                          $3))))
               MYSQL_YYABORT;
-            Select->add_joined_table($$);
+            TABLE_LIST *tl= $$;
+            Select->add_joined_table(tl);
             if ($4)
-              $$->vers_conditions= Lex->vers_conditions;
+              tl->vers_conditions= Lex->vers_conditions;
           }
         ;
 

sql/table.h

@@ -1848,7 +1848,6 @@ class Vers_history_point : public vers_history_point_t
 struct vers_select_conds_t
 {
   vers_system_time_t type;
-  bool from_query:1;
   bool used:1;
   Vers_history_point start;
   Vers_history_point end;
@@ -1856,7 +1855,7 @@ struct vers_select_conds_t
   void empty()
   {
     type= SYSTEM_TIME_UNSPECIFIED;
-    used= from_query= false;
+    used= false;
     start.empty();
     end.empty();
   }
@@ -1866,7 +1865,7 @@ struct vers_select_conds_t
             Vers_history_point _end= Vers_history_point())
   {
     type= _type;
-    used= from_query= false;
+    used= false;
     start= _start;
     end= _end;
   }
@@ -1880,10 +1879,6 @@ struct vers_select_conds_t
     return type != SYSTEM_TIME_UNSPECIFIED;
   }
   bool resolve_units(THD *thd);
-  bool user_defined() const
-  {
-    return !from_query && type != SYSTEM_TIME_UNSPECIFIED;
-  }
   bool eq(const vers_select_conds_t &conds) const;
 };