Save and clear run context before executing a stored function or trigger and restore it afterwards.

This allows us to use statement replication with functions and triggers
The following things are fixed with this patch:
- NOW() and automatic timestamps takes the value from the main event for functions and triggers (which allows these to replicate with statement level logging)
- No side effects for triggers or functions with auto-increment values(), last_insert_id(), rand() or found_rows()
- Triggers can't return result sets

Fixes bugs:
#12480: NOW() is not constant in a trigger
#12481: Using NOW() in a stored function breaks statement based replication
#12482: Triggers has side effects with auto_increment values
#11587: trigger causes lost connection error


mysql-test/r/trigger.result:
  Added test fpr big
mysql-test/t/sp-error.test:
  Changed error message numbers
mysql-test/t/trigger.test:
  Added test for trigger returning result (#11587)
sql/item_func.cc:
  Store the first used seed value for RAND() value.
  (This makes rand() replicatable in functions and triggers)
  Save and clear run context before executing a stored function and restore it afterwards.
  This removes side effects of stored functions for RAND(), auto-increment values and NOW() and makes most stored function replicatable
sql/share/errmsg.txt:
  Reuse error message also for triggers
sql/sp_head.cc:
  If in function or trigger, don't change value of NOW()
  (This allows us to use statement replication with functions that directly or indirectly uses timestamps)
sql/sql_class.cc:
  Added framework for storing and retrieving run context while exceuting triggers or stored functions.
sql/sql_class.h:
  Added framework for storing and retrieving run context while exceuting triggers or stored functions.
sql/sql_parse.cc:
  If in function or trigger, don't change value of NOW()
  (This allows us to use statement replication with functions that directly or indirectly uses timestamps)
sql/sql_trigger.cc:
  Moved process_triggers function from sql_trigger.h
  Use reset/restore sub_statement_state while executing triggers to avoid side effects and make them replicatable
sql/sql_trigger.h:
  Moved process_triggers function from sql_trigger.h
  Use reset/restore sub_statement_state while executing triggers to avoid side effects and make them replicatable
sql/sql_yacc.yy:
  Give error message if trigger can return a result set (Bug #11587)
tests/fork_big2.pl:
  Removed return from end of lines
mysql-test/r/rpl_trigger.result:
  New BitKeeper file ``mysql-test/r/rpl_trigger.result''
mysql-test/t/rpl_trigger.test:
  New BitKeeper file ``mysql-test/t/rpl_trigger.test''

1 files changed, 36 insertions, 0 deletions

diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index 09eeff02de6..053dfdfc990 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -869,3 +869,39 @@ end:
   free_root(&table.mem_root, MYF(0));
   DBUG_RETURN(result);
 }
+
+
+
+bool Table_triggers_list::process_triggers(THD *thd, trg_event_type event,
+                                           trg_action_time_type time_type,
+                                           bool old_row_is_record1)
+{
+  int res= 0;
+
+  if (bodies[event][time_type])
+  {
+    Sub_statement_state statement_state;
+
+    if (old_row_is_record1)
+    {
+      old_field= record1_field;
+      new_field= table->field;
+    }
+    else
+    {
+      new_field= record1_field;
+      old_field= table->field;
+    }
+
+    /*
+      FIXME: We should juggle with security context here (because trigger
+      should be invoked with creator rights).
+    */
+
+    thd->reset_sub_statement_state(&statement_state, SUB_STMT_TRIGGER);
+    res= bodies[event][time_type]->execute_function(thd, 0, 0, 0);
+    thd->restore_sub_statement_state(&statement_state);
+  }
+
+  return res;
+}