This commit implements aggregate stored functions. The basic idea behind
the feature is:
* Implement a special instruction FETCH GROUP NEXT ROW that will pause
the execution of the stored function. When the instruction is reached,
execution of the initial query resumes "as if" the function returned.
This gives the server the opportunity to advance to the next row in the
result set.
* Stored aggregates behave like regular aggregate functions. The
implementation of thus resides in the class Item_sum_sp. Because it is
an aggregate function, for each new row in the group, the
Item_sum_sp::add() method will be called. This is when execution resumes
and the function does another iteration to "add" one extra element to
the final result.
* When the end of group is reached, val_xxx() method will be called for
the item. This case is handled by another execute step for the stored
function, only with a special flag to force a call to the return
handler. See Item_sum_sp::execute() for details.
To allow this pause and resume semantic, we must preserve the function
context across executions. This is stored in Item_sp::sp_query_arena only for
aggregate stored functions, but has no impact for regular functions.
We also enforce aggregate functions to include the "FETCH GROUP NEXT ROW"
instruction.
Signed-off-by: Vicențiu Ciorbaru <vicentiu@mariadb.org>
As a result of this merge the code for the following tasks appears in 10.3:
- MDEV-12172 Implement tables specified by table value constructors
- MDEV-12176 Transform [NOT] IN predicate with long list of values INTO
[NOT] IN subquery.
This is a 10.3 specific part of MDEV-13049.
It disables automatic sorting for
"SELECT .. FROM INFORMATION_SCHEMA.{SCHEMATA|TABLES}"
and adjusts the affected tests accordingly.
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.
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
ORDER BY does not work
Use "dynamic" row format (instead of "block") for MARIA internal
temporary tables created for cursors.
With "block" row format MARIA may shuffle rows, with "dynamic" row
format records are inserted sequentially (there are no gaps in data
file while we fill temporary tables).
This is needed to preserve row order when scanning materialized cursors.
Now we only execute the innermost of them (the most relevant).
The solution was to add a 'handled' marker to MYSQL_ERROR and mark all elements for which we have executed a condition handler.
When searching for new conditions, we will ignore any marked element.
.bzrignore:
Ignore error message file
mysql-test/r/sp.result:
Added testcase for continue handlers.
mysql-test/t/sp.test:
Added testcase for continue handlers.
sql/sp_head.cc:
Mark errors for which we will excute a handler as 'handled'
Ignore already handled warnings/errors
sql/sql_error.cc:
Add 'handled' argument to MYSQL_ERROR, so that we can mark the errors/warnings we have handled.
sql/sql_error.h:
Add 'handled' argument to MYSQL_ERROR, so that we can mark the errors/warnings we have handled.
