Fix for bug #12704 "Server crashes during trigger execution".

This bug occurs when some trigger for table used by DML statement is created
or changed while statement was waiting in lock_tables(). In this situation
prelocking set which we have calculated becames invalid which can easily lead
to errors and even in some cases to crashes.

With proposed patch we no longer silently reopen tables in lock_tables(),
instead caller of lock_tables() becomes responsible for reopening tables and
recalculation of prelocking set.

1 files changed, 19 insertions, 0 deletions

diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index 053dfdfc990..7342c146045 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -511,6 +511,25 @@ bool Table_triggers_list::prepare_record1_accessors(TABLE *table)
 
 
 /*
+  Adjust Table_triggers_list with new TABLE pointer.
+
+  SYNOPSIS
+    set_table()
+      new_table - new pointer to TABLE instance
+*/
+
+void Table_triggers_list::set_table(TABLE *new_table)
+{
+  table= new_table;
+  for (Field **field= table->triggers->record1_field ; *field ; field++)
+  {
+    (*field)->table= (*field)->orig_table= new_table;
+    (*field)->table_name= &new_table->alias;
+  }
+}
+
+
+/*
   Check whenever .TRG file for table exist and load all triggers it contains.
 
   SYNOPSIS