The intent of this patch is to avoid copying arguments from
a pair "Item **args, uint arg_count" to List<Item> in
sp_head::execute_function(). If the number of a stored function parameters
is huge, such copying can affect performance.
Change:
1. Adding a new method Row_definition_list::adjust_formal_params_to_actual_params,
which accepts a pair of "Item **, uint".
2. Modifying the code to use the new method:
- the calls for sp_rcontext::retrieve_field_definitions() and
Row_definition_list::adjust_formal_params_to_actual_params() have
been moved from sp_rcontext::create() to sp_head::rcontext_create(),
to handle different argument notations easier (Item** vs List<Item>).
- sp_rcontext::create() now assumes that the passed Row_definition_list
is already adjusted to the actual SP parameters, and all "TYPE OF"
and "ROWTYPE OF" references are resolved.
3. Removing creation of List<Item> in sp_head::execute_procedure(),
using the code with "Item**, uint" notation instead.
4. Improvement of the code for MDEV-10577:
As a good side effect, this patch gets rid of double security context
switch inside sp_head::execute_trigger():
sp_rcontext is created when the context is already switched,
so the second context switch inside sp_head::rcontext_create() was
redundant. This is solved by adding a "bool switch_secutiry_ctx" parameter
to rcontext_create(), so now execute_function() and execute_procedure()
pass "true", while execute_trigger() passes "false".
- Added sql/mariadb.h file that should be included first by files in sql
directory, if sql_plugin.h is not used (sql_plugin.h adds SHOW variables
that must be done before my_global.h is included)
- Removed a lot of include my_global.h from include files
- Removed include's of some files that my_global.h automatically includes
- Removed duplicated include's of my_sys.h
- Replaced include my_config.h with my_global.h
Benefits of this patch:
- Removed a lot of calls to strlen(), especially for field_string
- Strings generated by parser are now const strings, less chance of
accidently changing a string
- Removed a lot of calls with LEX_STRING as parameter (changed to pointer)
- More uniform code
- Item::name_length was not kept up to date. Now fixed
- Several bugs found and fixed (Access to null pointers,
access of freed memory, wrong arguments to printf like functions)
- Removed a lot of casts from (const char*) to (char*)
Changes:
- This caused some ABI changes
- lex_string_set now uses LEX_CSTRING
- Some fucntions are now taking const char* instead of char*
- Create_field::change and after changed to LEX_CSTRING
- handler::connect_string, comment and engine_name() changed to LEX_CSTRING
- Checked printf() related calls to find bugs. Found and fixed several
errors in old code.
- A lot of changes from LEX_STRING to LEX_CSTRING, especially related to
parsing and events.
- Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING*
- Some changes for char* to const char*
- Added printf argument checking for my_snprintf()
- Introduced null_clex_str, star_clex_string, temp_lex_str to simplify
code
- Added item_empty_name and item_used_name to be able to distingush between
items that was given an empty name and items that was not given a name
This is used in sql_yacc.yy to know when to give an item a name.
- select table_name."*' is not anymore same as table_name.*
- removed not used function Item::rename()
- Added comparision of item->name_length before some calls to
my_strcasecmp() to speed up comparison
- Moved Item_sp_variable::make_field() from item.h to item.cc
- Some minimal code changes to avoid copying to const char *
- Fixed wrong error message in wsrep_mysql_parse()
- Fixed wrong code in find_field_in_natural_join() where real_item() was
set when it shouldn't
- ER_ERROR_ON_RENAME was used with extra arguments.
- Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already
give the error.
TODO:
- Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c
- Change code to not modify LEX_CSTRING for database name
(as part of lower_case_table_names)
Parse context frames (sp_pcontext) can have holes in variable run-time offsets,
the missing offsets reside on the children contexts in such cases.
Example:
CREATE PROCEDURE p1() AS
x0 INT:=100; -- context 0, position 0, run-time 0
CURSOR cur(
p0 INT, -- context 1, position 0, run-time 1
p1 INT -- context 1, position 1, run-time 2
) IS SELECT p0, p1;
x1 INT:=101; -- context 0, position 1, run-time 3
BEGIN
...
END;
Fixing a few methods to take this into account:
- sp_pcontext::find_variable()
- sp_pcontext::retrieve_field_definitions()
- LEX::sp_variable_declarations_init()
- LEX::sp_variable_declarations_finalize()
- LEX::sp_variable_declarations_rowtype_finalize()
- LEX::sp_variable_declarations_with_ref_finalize()
Adding a convenience method:
sp_pcontext::get_last_context_variable(uint offset_from_the_end);
to access variables from the end, rather than from the beginning.
This helps to loop through the context variable array (m_vars)
on the fragment that does not have any holes.
Additionally, renaming sp_pcontext::find_context_variable() to
sp_pcontext::get_context_variable(). This method simply returns
the variable by its index. So let's rename to avoid assumptions
that some heavy lookup is going on inside.
Fixed that the Column_definition::pack_flag member corresponding to
ROW-type SP variables and their fields was not properly initialized.
This lead to sporadic test failures. Valgrind complained about jumps
depending on uninitialized value in VALGRIND builds.
This patch makes sure that sp_head::fill_spvar_definition() is always
called for ROW variables and their fields.
Additionally, fixed that a function with a scalar parameter
erroneously acceptes ROWs with one fields. Now an error is returned.
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.
The bug was introduced in the patch for "MDEV-10597 Cursors with parameters".
The LEX created in assignment_source_expr was not put into
thd->lex->sphead->m_lex (the stack of LEX'es), so syntax error in "expr"
caused a wrong memory cleanup in sp_head::~sp_head().
The fix changes the code to use sp_head::push_lex() followed by
sp_head::restore_lex(), like it happens in all other similar cases.
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)
Some upcoming tasks, e.g.:
- MDEV-10577 sql_mode=ORACLE: %TYPE in variable declarations
- MDEV-10914 ROW data type for stored routine variables
will need to reuse the code implemented in prepare_create_field(),
sp_prepare_create_field(), prepare_blob_field().
Before reusing this code, it's a good idea to move these global functions
as methods to Column_definition.
This patch:
- actually moves prepare_create_field(), sp_prepare_create_field(),
prepare_blob_field() as methods to Column_definition
- makes sp_prepare_create_field() call prepare_create_field() at the end,
to avoid duplicate code in MDEV-10577 and MDEV-10914.
- changes the return data type for prepare_create_field() from int to bool,
to make it consistent with all other functions returning "ok" or "error".
- moves the implementation sp_head::fill_field_definition() from sp_head.cc
to sp_head.h, as it now uses globally visible Column_definition methods,
and is very simple, so inlining is now possible.
- removes the unused "LEX*" argument from sp_head::fill_field_definition()
