Implementing cursor%ROWTYPE variables, according to the task description.
This patch includes a refactoring in how sp_instr_cpush and sp_instr_copen
work. This is needed to implement MDEV-10598 later easier, to allow variable
declarations go after cursor declarations (which is currently not allowed).
Before this patch, sp_instr_cpush worked as a Query_arena associated with
the cursor. sp_instr_copen::execute() switched to the sp_instr_cpush's
Query_arena when executing the cursor SELECT statement.
Now the Query_arena associated with the cursor is stored inside an instance
of a new class sp_lex_cursor (a LEX descendand) that contains the cursor SELECT
statement.
This simplifies the implementation, because:
- It's easier to follow the code when everything related to execution
of the cursor SELECT statement is stored inside the same sp_lex_cursor
object (rather than distributed between LEX and sp_instr_cpush).
- It's easier to link an sp_instr_cursor_copy_struct to
sp_lex_cursor rather than to sp_instr_cpush.
- Also, it allows to perform sp_instr_cursor_copy_struct::exec_core()
without having a pointer to sp_instr_cpush, using a pointer to sp_lex_cursor
instead. This will be important for MDEV-10598, because sp_instr_cpush will
happen *after* sp_instr_cursor_copy_struct.
After MDEV-10598 is done, this declaration:
DECLARE
CURSOR cur IS SELECT * FROM t1;
rec cur%ROWTYPE;
BEGIN
OPEN cur;
FETCH cur INTO rec;
CLOSE cur;
END;
will generate about this code:
+-----+--------------------------+
| Pos | Instruction |
+-----+--------------------------+
| 0 | cursor_copy_struct rec@0 | Points to sp_cursor_lex through m_lex_keeper
| 1 | set rec@0 NULL |
| 2 | cpush cur@0 | Points to sp_cursor_lex through m_lex_keeper
| 3 | copen cur@0 | Points to sp_cursor_lex through m_cursor
| 4 | cfetch cur@0 rec@0 |
| 5 | cclose cur@0 |
| 6 | cpop 1 |
+-----+--------------------------+
Notice, "cursor_copy_struct" and "set" will go before "cpush".
Instructions at positions 0, 2, 3 point to the same sp_cursor_lex instance.
Adding methods:
- LEX::sp_while_loop_expression()
- LEX::sp_while_loop_finalize()
to reuse code between sql_yacc.yy and sql_yacc_ora.yy.
FOR loop will also reuse these methods.
Part 5: EXIT statement
Adding unconditional EXIT statement:
EXIT [ label ]
Conditional EXIT statements with WHERE clause
will be added in a separate patch.
Moving similar code from sql_yacc.yy and sql_yacc_ora.yy to methods:
LEX::maybe_start_compound_statement()
LEX::sp_push_loop_label()
LEX::sp_push_loop_empty_label()
LEX::sp_pop_loop_label()
LEX::sp_pop_loop_empty_label()
The EXIT statement will also reuse this code.
Moving the code from *.yy to methods:
LEX::sp_change_context()
LEX::sp_leave_statement()
LEX::sp_iterate_statement()
to reuse the same code between LEAVE and ITERATE statements.
EXIT statement will also reuse the same code.
When processing an SP body:
CREATE PROCEDURE p1 (parameters)
AS [ declarations ]
BEGIN statements
[ EXCEPTION exceptions ]
END;
the parser generates two "jump" instructions:
- from the end of "declarations" to the beginning of EXCEPTION
- from the end of EXCEPTION to "statements"
These jumps are useless if EXCEPTION does not exist.
This patch makes sure that these two "jump" instructions are
generated only if EXCEPTION really exists.
- Part 9: EXCEPTION handlers
The top-most stored routine blocks now support EXCEPTION clause
in its correct place:
AS [ declarations ]
BEGIN statements
[ EXCEPTION exceptions ]
END
Inner block will be done in a separate commit.
- Part 14: IN OUT instead of INOUT (in SP parameter declarations)
1. Adding const qualifiers into a few method parameters.
2. Adding methods:
- sp_label::block_label_declare()
- LEX::sp_block_init()
- LEX::sp_block_finalize()
to share more code between the files sql_yacc.yy and sql_yacc_ora.yy,
as well as between the rules sp_labeled_block, sp_unlabeled_block,
sp_unlabeled_block_not_atomic.
3. sql_yacc.yy, sql_yacc_ora.yy changes:
- Removing sp_block_content
- Reorganizing the grammar so the rules sp_labeled_block,
sp_unlabeled_block, sp_unlabeled_block_not_atomic now
contain both BEGIN_SYM and END keywords. Previously,
BEGIN_SYM and END resided in different rules.
This change makes the grammar easier to read,
as well as simplifies adding Oracle-style DECLARE section (coming soon):
DECLARE
..
BEGIN
..
END;
Good side effects:
- SP block related grammar does not use Lex->name any more.
- The "splabel" member was removed from %union
- Adding a new grammar file sql_yacc_ora.yy, which is currently
almost a full copy of sql_yacc.yy.
Note, it's now assumed that sql_yacc.yy and sql_yacc_ora.yy
use the same set of %token directives and exactly the same
%union directive.
These declarations should eventually be moved into a shared
included file, to make sure that sql_yacc.h and sql_yacc_ora.h
are compatible.
- Removing the "-p MYSQL" flag from cmake/bison.cmake, using
the %name-prefix directive inside sql_yacc.yy and sql_yacc_ora.yy instead
- Adding other CMake related changes to build sql_yacc_ora.o
form sql_yacc_ora.yy
- Adding NUMBER(M,N) as a synonym to DECIMAL(M,N) as the first
Oracle compatibility syntax understood in sql_mode=ORACLE.
- Adding prototypes to functions add_virtual_expression()
and handle_sql2003_note184_exception(), so they can be used
in both sql_yacc.yy and sql_yacc_ora.yy.
- Adding a new test suite compat/oracle, with the first test "type_number".
Use this:
./mtr compat/oracle.type_number # to run a single test
./mtr --suite=compat/oracle # to run the entire new suite
- Adding compat/oracle into the list of default suites,
so BuildBot can run it automatically on pushes.
Define my_thread_id as an unsigned type, to avoid mismatch with
ulonglong. Change some parameters to this type.
Use size_t in a few more places.
Declare many flag constants as unsigned to avoid sign mismatch
when shifting bits or applying the unary ~ operator.
When applying the unary ~ operator to enum constants, explictly
cast the result to an unsigned type, because enum constants can
be treated as signed.
In InnoDB, change the source code line number parameters from
ulint to unsigned type. Also, make some InnoDB functions return
a narrower type (unsigned or uint32_t instead of ulint;
bool instead of ibool).
This is an extraction from the patch for MDEV-10577, which is not
directly related to %TYPE implementation. This patch does the following:
- Moves LEX::set_last_field_type() to Column_definition::set_attributes()
- Adds initialization of Column_definition members length, decimals,
charset, on_update into the constructor.
- Column_definition::set_attributes() now does not set length and decimal
to 0 any more, as they are not initialized in the constructor.
- Move Column_definition::prepare_interval_field() from field.h to field.cc,
as it's too huge.
Moving another banch of functions implemented in sql_yacc.yy as methods to LEX,
to be able to reuse them between sql_yacc.yy and sql_yacc_ora.yy easier.
The list of functions:
- add_create_index_prepare()
- add_key_to_list()
- set_trigger_new_row()
- set_local_variable()
- set_system_variable()
- create_item_for_sp_var()
The full list of functions moved:
int case_stmt_action_expr(LEX *, Item* expr);
int case_stmt_action_when(LEX *, Item *when, bool simple);
int case_stmt_action_then(LEX *);
bool add_select_to_union_list(LEX *,bool is_union_distinct, bool is_top_level);
This is a preparatory change for "MDEV-10142 PL/SQL parser",
to reuse the code easier between sql_yacc.yy and coming soon sql_yacc_ora.yy.
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.
