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MDEV-13417 UPDATE produces wrong values if an updated column is later used as an update source

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Standard compatible behavior for UPDATE: all assignments in SET
are executed "simultaneously", not left-to-right. And `SET a=b,b=a`
will swap the values.
This commit is contained in:
Jerome Brauge
2018-01-29 16:53:39 +01:00
committed by Sergei Golubchik
parent 355ee6877b
commit d943d7f712
29 changed files with 566 additions and 76 deletions
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40
sql/sql_base.cc
View File

@ -8107,6 +8107,8 @@ fill_record(THD *thd, TABLE *table_arg, List<Item> &fields, List<Item> &values,
List_iterator_fast<Item> f(fields),v(values);
Item *value, *fld;
Item_field *field;
Field *rfield;
TABLE *table;
bool only_unvers_fields= update && table_arg->versioned();
bool save_abort_on_warning= thd->abort_on_warning;
bool save_no_errors= thd->no_errors;
@ -8140,8 +8142,8 @@ fill_record(THD *thd, TABLE *table_arg, List<Item> &fields, List<Item> &values,
}
value=v++;
DBUG_ASSERT(value);
Field *rfield= field->field;
TABLE* table= rfield->table;
rfield= field->field;
table= rfield->table;
if (table->next_number_field &&
rfield->field_index == table->next_number_field->field_index)
table->auto_increment_field_not_null= TRUE;
@ -8162,15 +8164,41 @@ fill_record(THD *thd, TABLE *table_arg, List<Item> &fields, List<Item> &values,
if (only_unvers_fields && !rfield->vers_update_unversioned())
only_unvers_fields= false;
if (rfield->stored_in_db() &&
(value->save_in_field(rfield, 0)) < 0 && !ignore_errors)
if (rfield->stored_in_db())
{
my_message(ER_UNKNOWN_ERROR, ER_THD(thd, ER_UNKNOWN_ERROR), MYF(0));
goto err;
if (value->save_in_field(rfield, 0) < 0 && !ignore_errors)
{
my_message(ER_UNKNOWN_ERROR, ER_THD(thd, ER_UNKNOWN_ERROR), MYF(0));
goto err;
}
/*
In sql MODE_SIMULTANEOUS_ASSIGNMENT,
move field pointer on value stored in record[1]
which contains row before update (see MDEV-13417)
*/
if (update && thd->variables.sql_mode & MODE_SIMULTANEOUS_ASSIGNMENT)
rfield->move_field_offset((my_ptrdiff_t) (table->record[1] -
table->record[0]));
}
rfield->set_explicit_default(value);
}
if (update && thd->variables.sql_mode & MODE_SIMULTANEOUS_ASSIGNMENT)
{
// restore fields pointers on record[0]
f.rewind();
while ((fld= f++))
{
rfield= fld->field_for_view_update()->field;
if (rfield->stored_in_db())
{
table= rfield->table;
rfield->move_field_offset((my_ptrdiff_t) (table->record[0] -
table->record[1]));
}
}
}
if (!update && table_arg->default_field &&
table_arg->update_default_fields(0, ignore_errors))
goto err;