Item_ref::val_(datetime|time)_packed() erroneously called
(*ref)->val_(datetime|time)_packed().
- Fixing to call (*ref)->val_(datetime|time)_packed_result().
- Backporting Item::val_(datetime|time)_packed_result() from 10.3.
- Fixing Item_field::get_date_result() to handle null_value in the same
way how Item_field::get_date() does.
The issue here is window function makes the passed string object
to point to an area in a temporary table's record buffer.
Then, the temporary table is freed, together with its record buffer.
Then, Item_cache_str attempts to read this value.
The fix is to call value_buff.copy(). This will make the value_buff to store
its string in a buffer that it owns, which will not disappear unexpectedly.
remove a special treatment of a bare DEFAULT keyword that made it
behave inconsistently and differently from DEFAULT(column).
Now all forms of the explicit assignment of a default column value
behave identically, and all count as an explicitly assigned value
(for the purpose of ON UPDATE NOW).
followup for c7c481f4d9
and WHERE filter afterwards
This patch complements the patch fixing the bug MDEV-6892. The latter
properly handled queries that used mergeable views returning constant
columns as inner tables of outer joins and whose where clause contained
predicates referring to these columns if the predicates of happened not
to be equality predicates. Otherwise the server still could return wrong
result sets for such queries. Besides the fix for MDEV-6892 prevented
some possible conversions of outer joins to inner joins for such queries.
This patch corrected the function check_simple_equality() to handle
properly conjunctive equalities of the where clause that refer to the
constant columns of mergeable views used as inner tables of an outer join.
The patch also changed the code of Item_direct_view_ref::not_null_tables().
This change allowed to take into account predicates containing references
to constant columns of mergeable views when converting outer joins into
inner joins.
The issue here was when we had a subquery and a window function in an expression in
the select list then subquery was getting computed after window function computation.
This resulted in incorrect results because the subquery was correlated and the fields
in the subquery was pointing to the base table instead of the temporary table.
The approach to fix this was to have an additional field in the temporary table
for the subquery and to execute the subquery before window function execution.
After execution the values for the subquery were stored in the temporary table
and then when we needed to calcuate the expression, all we do is read the values
from the temporary table for the subquery.
ASAN noticed a freed memory access during EXECUTE in this script:
PREPARE stmt FROM "SELECT 'x' ORDER BY NAME_CONST( 'f', 'foo' )";
EXECUTE stmt;
In case of a PREPARE statement, all Items, including Item_name_const,
are created on Prepared_statement::main_mem_root.
Item_name_const::fix_fields() did not take this into account
and could allocate the value of Item::name on a wrong memory root,
in this code:
if (is_autogenerated_name)
{
set_name(thd, item_name->c_ptr(), (uint) item_name->length(),
system_charset_info);
}
When fix_fields() is called in the reported SQL script, THD's arena already
points to THD::main_mem_root rather than to Prepared_statement::main_mem_root,
so Item::name was allocated on THD::main_mem_root.
Then, at the end of the dispatch_command() for the PREPARE statement,
THD::main_mem_root got cleared. So during EXECUTE, Item::name
pointed to an already freed memory.
This patch changes the code to set the implicit name for Item_name_const
at the constructor time rather than at fix_fields time. This guarantees
that Item_name_const and its Item::name always reside on the same memory root.
Note, this change makes the code for Item_name_const symmetric with other
constant-alike items that set their default implicit names at the constructor
call time rather than at fix_fields() time:
- Item_string
- Item_int
- Item_real
- Item_decimal
- Item_null
- Item_param
While printing a view containing a window function we were printing it as an
Item_field object instead of an Item_window_func object. This is incorrect and this
leads to us throwing an error ER_VIEW_INVALID.
Fixed by adjusting the Item_ref:print function.
Also made UDF function aware if there arguments have window function.
The error message modified.
Then the TABLE_SHARE::error_table_name() implementation taken from 10.3,
to be used as a name of the table in this message.
- clean up DEFAULT() to work only with default value and correctly print
itself.
- fix of DBUG_ASSERT about fields read/write
- fix of field marking for write based really on the thd->mark_used_columns flag
Item_direct_view_ref::derived_field_transformer_for_where
upon updating a view
The condition pushed into a materialized derived / view mast be adjusted
for the new context: its column references must be substituted for
references to the columns of the underlying tables if the condition
is pushed into WHERE. The substitution is performed by the 'transform'
method. If the materialized derived is used in a mergeable view then
the references to the columns of the view are represented by
Item_direct_view_ref objects. The transform method first processes
the item wrapped in such an object and only after this it transforms
the object itself.
The transformation procedure of an Item_direct_view_ref object has
to know whether the item it wraps has been substituted. If so the
procedure does not have to do anything. In the code before this patch
it was not possible for the transformation procedure used by an
Item_direct_view_ref object to find out whether a substitution for
the wrapped item had happened.
upon INSERT .. SELECT
The function Item *Item_direct_view_ref::derived_field_transformer_for_where()
erroneously did not strip off ref wrappers from references to materialized
derived tables / views. As a result the expressions that contained some
references of the type Item_direct_view_ref to columns of a materialized
derived table / view V were pushed into V incorrectly. This could cause
crashes for some INSERT ... SELECT statements.
