The fix for bug mdev-11488 introduced the virtual method
convert_to_basic_const_item for the class Item_cache.
The implementation of this method for the class Item_cache_str
was not quite correct: the server could crash if the cached item
was null.
A similar problem could appear for the implementation of
this method for the class Item_cache_decimal. Although I could not
reproduce the problem I decided to change the code appropriately.
The bug occurred when a subquery
- has a reference to outside, to grand-parent query or further up
- is converted to a semi-join (i.e. merged into its parent).
Then the reference to outside had form Item_ref(Item_field(...)).
- Conversion to semi-join would call item->fix_after_pullout() for the
outside reference.
- Item_ref::fix_after_pullout would call Item_field->fix_after_pullout
- The Item_field would construct a new Name_resolution_context object
This process ignored the fact that the Item_field does not belong to
any of the subselects being flattened.
The result was crash in the next call to Item_field::fix_fields(), where
we would try to use an invalid Name_resolution_context object.
Fixed by not creating Name_resolution_context object if the Item_field's
context does not belong to the subselect(s) that were flattened.
This patch:
- Adds a new virtual method Type_handler::Item_get_cache
- Splits moves Item_cache::get_cache() into the new method, every
"case XXX_RESULT" to the corresponding Type_handler_xxx::Item_get_cache.
- Adds Item::get_cache as a convenience wrapper, to make the caller code
shorter.
- Changes the last argument of Arg_comparator::cache_converted_constant()
from Item_result to "const Type_handler *".
- Removes subselect_engine::cmp_type, subselect_engine::res_type,
subselect_engine::res_field_type and derives subselect_engine
from Type_handler_hybrid_field_type instead.
- Makes Type_handler_varchar public, as it's now needed as the
default data type handler for subselect_engine.
Also fixes:
MDEV-11331 Wrong result for INSERT INTO t1 (datetime_field) VALUES (hybrid_function_of_TIME_data_type)
MDEV-11333 Expect "Impossible where condition" for WHERE timestamp_field>=DATE_ADD(TIMESTAMP'9999-01-01 00:00:00',INTERVAL 1000 YEAR)
This patch does the following:
1. Splits the function Item::save_in_field() into pieces:
- Item::save_str_in_field()
- Item::save_real_in_field()
- Item::save_decimal_in_field()
- Item::save_int_in_field()
2. Adds the missing "no_conversion" parameters to
Item::save_time_in_field() and Item::save_date_in_field(),
so this parameter is now correctly passed to
set_field_to_null_with_conversions().
This fixes the problem reported in 11333.
3. Introduces a new virtual method Type_handler::Item_save_in_field()
and uses the methods Item::save_xxx_in_field() from the implementations
of Type_handler_xxx::Item_save_in_field().
These changes additionally fix the problem reported in MDEV-11331,
as the old code erroneously handled expressions like
COALESE(datetime-expression) through the STRING_RESULT branch of
Item::save_in_field() and therefore they looked like string type expressions
for the target fields. Now such expressions are correctly handled by
Item::save_date_in_field().
The patch for bug mdev-10882 tried to fix it by providing an
implementation of the virtual method build_clone for the class
Item_cache. It's turned out that it is not easy provide a valid
implementation for Item_cache::build_clone(). At the same time
if the condition that can be pushed into a materialized view
contains a cached item this item can be substituted for a basic
constant of the same value. In such a way we can avoid building
proper clones for Item_cache objects when constructing pushdown
conditions.
otherwise we'd need to store sql_mode *per vcol*
(consider CREATE INDEX...) and how SHOW CREATE TABLE would
support that?
Additionally, get rid of vcol::expr_str, just to make sure
the string is always generated and never leaked in the
original form.
The problem was that null_value was not set to "false" on a well-formed row.
If an ill-formed row was followed by a well-forned row, null_value remained
"true" in the call of Item::send() for the well-formed row.
This patch adds DEFAULT as a possible dynamic SQL parameter, e.g.:
EXECUTE IMMEDIATE 'INSERT INTO t1 (column) VALUES(?)' USING DEFAULT;
EXECUTE IMMEDIATE 'UPDATE t1 SET column=?' USING DEFAULT;
and for similar PREPARE..EXECUTE queries.
This is done for symmetry with the STMT_INDICATOR_DEFAULT indicator in
the client-server PS protocol.
The changes include:
- Allowing DEFAULT as a possible option in execute USING clause (sql_yacc.yy)
- Adding "virtual bool Item::save_in_param(THD *thd, Item_param *param)",
because "normal" items (that have real values) and Item_default_value
have now different actions when assigning itself as an Item_param value.
- Fixing switch() statements in a few Item_param methods not to have "default",
because it was easy to forget to add a new "case" when adding a new XXX_VALUE
value into the enum Item_param::enum_item_param_state.
This is important, as we'll be adding new values soon, e.g. for MDEV-11359.
Removing "default" helped to find and report bugs MDEV-11361 and MDEV-11362,
because DECIMAL_VALUE is obviously not properly handled in some cases.
This is similar to MysQL Worklog 3253, but with
a different implementation. The disk format and
SQL syntax is identical with MySQL 5.7.
Fetures supported:
- "Any" ammount of any trigger
- Supports FOLLOWS and PRECEDES to be
able to put triggers in a certain execution order.
Implementation details:
- Class Trigger added to hold information about a trigger.
Before this trigger information was stored in a set of lists in
Table_triggers_list and in Table_triggers_list::bodies
- Each Trigger has a next field that poinst to the next Trigger with the
same action and time.
- When accessing a trigger, we now always access all linked triggers
- The list are now only used to load and save trigger files.
- MySQL trigger test case (trigger_wl3253) added and we execute these
identically.
- Even more gracefully handling of wrong trigger files than before. This
is useful if a trigger file uses functions or syntax not provided by
the server.
- Each trigger now has a "Created" field that shows when the trigger was
created, with 2 decimals.
Other comments:
- Many of the changes in test files was done because of the new "Created"
field in the trigger file. This shows up in SHOW ... TRIGGER and when
using information_schema.trigger.
- Don't check if all memory is released if on uses --gdb; This is needed
to be able to get a list from safemalloc of not freed memory while
debugging.
- Added option to trim_whitespace() to know how many prefix characters
was skipped.
- Changed a few ulonglong sql_mode to sql_mode_t, to find some wrong usage
of sql_mode.
Fix window function expressions such as win_func() <operator> expr.
The problem was found in 2 places.
First, when we have complex expressions containing window functions, we
can only compute their final value _after_ we have computed the window
function's values. These values must be stored within the temporary
table that we are using, before sending them off.
This is done by performing an extra copy_funcs call before the final
end_send() call.
Second, such expressions need to have their inner arguments,
changed such that the references within those arguments point to fields within
the temporary table.
Ex: sum(t.a) over (order by t.b) + sum(t.a) over (order by t.b)
Before this fix, t.a pointed to the original table's a field. In order
to compute the sum function's value correctly, it needs to point to the
copy of this field inside the temp table.
This is done by calling split_sum_func for each argument in the
expression in turn.
The win.test results have also been updated as they contained wrong
values for such a use case.
This bug in the code of Item_ref::build_clone could
cause corruption of items in where conditions.
Also made sure that equality predicates extracted
from multiple equality items to be pushed into
materialized views were cloned.
for materialized views and derived tables: there were no
push-down if the view was defined as union of selects
without aggregation. Added test cases with such unions.
Adjusted result files after the merge of the code for mdev-9197.
FROM I_S
Issue:
------
There is a difference in the field type created when the
following DDLs are used:
1) CREATE TABLE t0 AS SELECT NULL;
2) CREATE TABLE t0 AS SELECT GREATEST(NULL,NULL);
The first statement creates field of type Field_string and
the second one creates a field of type Field_null.
This creates a problem when the query mentioned in this bug
is used. Since the null_ptr is calculated differently for
Field_null.
Solution:
---------
When there is a function returning null in the select list
as mentioned above, the field should be of type
Field_string.
This was fixed in 5.6+ as part of Bug#14021323. This is a
backport to mysql-5.5.
An incorrect comment in innodb_bug54044.test has been
corrected in all versions.
Adding Converter_double_to_longlong and reusing it in:
1. Field_longlong::store(double nr)
2. Field_double::val_int()
3. Item::val_int_from_real()
4. Item_dyncol_get::val_int()
As a good side efferct, now overflow in conversion in the mentioned
val_xxx() methods return exactly the same warning.
