SQL: Default 'simple' algorithm for InnoDB 'AS OF' [closes #175]

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

@@ -149,6 +149,7 @@ a
 2
 select * from t for system_time before timestamp @ts1;
 a
+1
 select * from t for system_time before transaction 2000;
 a
 1
@@ -158,13 +159,11 @@ select * from t for system_time all;
 a
 11
 22
-1
 2
 truncate t for system_time before timestamp now(6);
 select * from t for system_time all;
 a
 11
 22
-2
 drop table t;
 drop procedure truncate_history_of_t;

sql/sql_class.h

@@ -710,6 +710,7 @@ typedef struct system_variables
   st_vers_current_time vers_current_time;
   my_bool vers_force;
   ulong vers_hide;
+  my_bool vers_innodb_algorithm_simple;
 } SV;
 
 /**

sql/sql_select.cc

@@ -771,8 +771,6 @@ int vers_setup_select(THD *thd, TABLE_LIST *tables, COND **where_expr,
     }
   }
 
-  const static bool vers_simple_select= false;
-
   for (table= tables; table; table= table->next_local)
   {
     if (table->table && table->table->versioned())
@@ -831,7 +829,10 @@ int vers_setup_select(THD *thd, TABLE_LIST *tables, COND **where_expr,
           newx Item_field(thd, &slex->context, table->db, table->alias, fend);
       Item *row_end2= row_end;
 
-      if (table->table->versioned_by_sql())
+      bool tmp_from_ib=
+          table->table->s->table_category == TABLE_CATEGORY_TEMPORARY &&
+          table->table->vers_start_field()->type() == MYSQL_TYPE_LONGLONG;
+      if (table->table->versioned_by_sql() && !tmp_from_ib)
       {
         if (vers_conditions.unit == UNIT_TRX_ID)
         {
@@ -839,8 +840,9 @@ int vers_setup_select(THD *thd, TABLE_LIST *tables, COND **where_expr,
           DBUG_RETURN(-1);
         }
       }
-      else if (vers_simple_select && vers_conditions.unit == UNIT_TIMESTAMP
-          && vers_conditions.type != FOR_SYSTEM_TIME_UNSPECIFIED)
+      else if (thd->variables.vers_innodb_algorithm_simple &&
+               vers_conditions.unit == UNIT_TIMESTAMP &&
+               vers_conditions.type != FOR_SYSTEM_TIME_UNSPECIFIED)
       {
         DBUG_ASSERT(table->table->s && table->table->s->db_plugin);
         handlerton *hton= plugin_hton(table->table->s->db_plugin);
@@ -859,19 +861,17 @@ int vers_setup_select(THD *thd, TABLE_LIST *tables, COND **where_expr,
       }
 
       Item *cond1= 0, *cond2= 0, *curr= 0;
-      // Temporary tables of type HEAP can be created from INNODB tables and
-      // thus will have uint64 type of sys_trx_(start|end) field.
+      // Temporary tables of can be created from INNODB tables and thus will
+      // have uint64 type of sys_trx_(start|end) field.
       // They need special handling.
       TABLE *t= table->table;
-      if ((t->s->table_category == TABLE_CATEGORY_TEMPORARY
-               ? t->vers_start_field()->type() != MYSQL_TYPE_LONGLONG
-               : t->versioned_by_sql()) ||
-          vers_simple_select)
+      if (tmp_from_ib || t->versioned_by_sql() ||
+          thd->variables.vers_innodb_algorithm_simple)
       {
         switch (vers_conditions.type)
         {
         case FOR_SYSTEM_TIME_UNSPECIFIED:
-          if (table->table->versioned_by_sql())
+          if (table->table->versioned_by_sql() && !tmp_from_ib)
           {
             MYSQL_TIME max_time;
             thd->variables.time_zone->gmt_sec_to_TIME(&max_time, TIMESTAMP_MAX_VALUE);

sql/sys_vars.cc

@@ -400,6 +400,12 @@ static Sys_var_enum Sys_vers_hide(
        "NEVER: don't hide system fields",
        SESSION_VAR(vers_hide), CMD_LINE(OPT_ARG), vers_hide_keywords, DEFAULT(VERS_HIDE_AUTO));
 
+static Sys_var_mybool Sys_vers_innodb_algorithm_simple(
+       "vers_innodb_algorithm_simple",
+       "Use simple algorithm of timestamp handling in InnoDB instead of TRX_SEES",
+       SESSION_VAR(vers_innodb_algorithm_simple), CMD_LINE(OPT_ARG),
+       DEFAULT(TRUE));
+
 static Sys_var_ulonglong Sys_binlog_cache_size(
        "binlog_cache_size", "The size of the transactional cache for "
        "updates to transactional engines for the binary log. "

storage/heap/ha_heap.cc

@@ -27,6 +27,9 @@
 #include "heapdef.h"
 #include "sql_base.h"                    // enum_tdc_remove_table_type
 
+bool vtq_query_trx_id(THD *thd, void *out, ulonglong in_trx_id,
+                      vtq_field_t field);
+
 static handler *heap_create_handler(handlerton *hton,
                                     TABLE_SHARE *table, 
                                     MEM_ROOT *mem_root);
@@ -56,6 +59,8 @@ int heap_init(void *p)
   heap_hton->panic=      heap_panic;
   heap_hton->flags=      HTON_CAN_RECREATE;
 
+  heap_hton->vers_query_trx_id = vtq_query_trx_id;
+
   return 0;
 }