The old behavior of returning the affected rows for the last statement
in a stored procedure was more an accident than design. Having the number
of affected rows for all sub statements is more useful and will not change
just because on changes the order of statements in the stored procedure.
The bug was caused by a defect of the patch for the bug 11081.
The patch was actually a port of the fix this bug from the mysql
code line. Later a correction of this fix was added to the
mysql code. Here's the comment this correction was provided with:
Bug#16499751: Opening cursor on SELECT in stored procedure causes segfault
This is a regression from the fix of bug#14740889.
The fix started using another set of expressions as the source for
the temporary table used for the materialized cursor. However,
JOIN::make_tmp_tables_info() calls setup_copy_fields() which creates
an Item_copy wrapper object on top of the function being selected.
The Item_copy objects were not properly handled by create_tmp_table -
they were simply ignored. This patch creates temporary table fields
based on the underlying item of the Item_copy objects.
The test case for the bug 13346 was taken from mdev-13380.
In the affected test chunk in sp.test, sql_mode is set to 0xFFFFFFFF,
which includes ORACLE, therefore an additional "AS" keyword is required:
CREATE PROCEDURE p1() AS BEGIN END;
Different fix. Don't allow Item_func_sp to be evaluated unless
all tables are prelocked.
Extend the test case to make sure Item_func_sp::val_str is called
(the table must have at least one row for that).
The idea of this fix was taken from the patch by Roy Lyseng
for mysql-5.6 bug iBug#14740889: "Wrong result for aggregate
functions when executing query through cursor".
Here's Roy's comment for his patch:
"
The problem was that a grouped query did not behave properly when
executed using a cursor. On further inspection, the query used one
intermediate temporary table for the grouping.
Then, Select_materialize::send_result_set_metadata created a temporary
table for storing the query result. Notice that get_unit_column_types()
is used to retrieve column meta-data for the query. The items contained
in this list are later modified so that their result_field points to
the row buffer of the materialized temporary table for the cursor.
But prior to this, these result_field objects have been prepared for
use in the grouping operation, by JOIN::make_tmp_tables_info(), hence
the grouping operation operates on wrong column buffers.
The problem is solved by using the list JOIN::fields when copying data
to the materialized table. This list is set by JOIN::make_tmp_tables_info()
and points to the columns of the last intermediate temporary table of
the executed query. For a UNION, it points to the temporary table
that is the result of the UNION query.
Notice that we have to assign a value to ::fields early in JOIN::optimize()
in case the optimization shortcuts due to a const plan detection.
A more optimal solution might be to avoid creating the final temporary
table when the query result is already stored in a temporary table.
"
The patch does not contain a test case, but the description of the
problem corresponds exactly what could be observed in the test
case for mdev-11081.
mysqld maintains a list of TABLE objects for all temporary
tables created within a session in THD. Here each table is
represented by a TABLE object.
A query referencing a particular temporary table for more
than once, however, failed with ER_CANT_REOPEN_TABLE error
because a TABLE_SHARE was allocate together with the TABLE,
so temporary tables always had only one TABLE per TABLE_SHARE.
This patch lift this restriction by separating TABLE and
TABLE_SHARE objects and storing TABLE_SHAREs for temporary
tables in a list in THD, and TABLEs in a list within their
respective TABLE_SHAREs.
DOING BAD DDL IN PREPARED STATEMENT
Analysis
========
A repeat execution of the prepared statement 'ALTER TABLE v1
CHECK PARTITION' where v1 is a view leads to server exit.
ALTER TABLE ... CHECK PARTITION is not applicable for views
and check for the same check is missing. This leads to
further execution and creation of derived table for the view
(Allocated under temp_table mem_root). Any reference to open
view or related pointers from second execution leads to
server exit as the same was freed at previous execution closure.
Fix:
======
Added check for view in mysql_admin_table() on PARTITION
operation. This will prevent mysql_admin_table() from
going ahead and creating temp table and related issues.
Changed message on admin table view operation error to
be more appropriate.
In original code, sometimes one got an automatic DEFAULT value in some cases, in other cases not.
For example:
create table t1 (a int primary key) - No default
create table t2 (a int, primary key(a)) - DEFAULT 0
create table t1 SELECT .... - Default for all fields, even if they where defined as NOT NULL
ALTER TABLE ... MODIFY could sometimes add an unexpected DEFAULT value.
The patch is quite big because we had some many test cases that used
CREATE ... SELECT or CREATE ... (...PRIMARY KEY(xxx)) which doesn't have an automatic DEFAULT anymore.
Other things:
- Removed warnings from InnoDB when waiting from semaphore (got this when testing things with --big)
The problem was with Materialized_cursor and temporary table it uses.
Temorary table's fields had Field::orig_table pointing to the tables
that were used in the query that produced data for the cursor.
When "FETCH INTO sp_var" statement is executed, those original tables
were already closed. However, copying from Materialized_cursor's table
into SP variable may cause field_conv() to be invoked which calls
field->type() which may access field->orig_table (for certain field types).
Fixed by setting Materialized_cursor->table->field[i]->orig_table to point
to Materialized_cursor->table. (this is how it is done for regular base
tables)
length/dec/charset are still in LEX, because they're also used
for CAST and dynamic columns.
also
1. fix "MDEV-7041 COLLATION(CAST('a' AS CHAR BINARY)) returns a wrong result"
2. allow BINARY modifier in stored function RETURN clause
3. allow "COLLATION without CHARSET" in SP/SF (parameters, RETURN, DECLARE)
4. print correct variable name in error messages for stored routine parameters
