sp_instr_cursor_copy_struct::exec_core() created TYPELIBs on a wrong mem_root,
the one which is initialized in sp_head::execute(), this code:
/* init per-instruction memroot */
init_sql_alloc(&execute_mem_root, "per_instruction_memroot",
MEM_ROOT_BLOCK_SIZE, 0, MYF(0));
This memory root cleans up after every sp_instr_xxx executed, so later
sp_instr_cfetch::execute() tried to use already freed and trashed memory.
Changing sp_instr_cursor_copy_struct::exec_core() to call tmp.export_structure()
inside this block (not outside of it):
thd->set_n_backup_active_arena(thd->spcont->callers_arena, ¤t_arena);
...
thd->restore_active_arena(thd->spcont->callers_arena, ¤t_arena);
So now TYPELIBs created by sp_instr_cursor_copy_struct::exec_core() are
still available and valid when sp_instr_cfetch::execute() is called.
They are freed at the end of dispatch_command() corresponding to
the "CALL p1" statement.
Changing the way how a cursor is opened to fetch its structure only,
e.g. for a cursor FOR loop record variable.
The old methods with setting thd->lex->limit_rows_examined to an Item_uint(0)
was not reliable and could push these messages into diagnostics area:
The query examined at least 1 rows, which exceeds LIMIT ROWS EXAMINED (0)
The new method should be more reliable, as it completely prevents the call
of do_select() in JOIN::exec_inner() during the cursor structure discovery,
so the execution of the cursor SELECT query returns immediately after the
preparation step (when the result row structure becomes known),
without even entering the code that fetches the result rows.
When processing a query containing with clauses a call of the function
check_dependencies_in_with_clauses() before opening tables used in the
query is necessary if with clauses include specifications of recursive
CTEs.
This call was missing if such a query belonged to a stored function.
This caused misbehavior of the server: it could report a fake error
as in the test case for MDEV-16629 or the executed query could hang
as in the test cases for MDEV-16661 and MDEV-15151.
Problem:
push_handler() created sp_handler_entry instances on THD::main_mem_root,
which is freed only after the SP instructions execution.
So in case of a CONTINUE HANDLER inside a loop (e.g. WHILE) this approach
leaked thread memory on every loop iteration.
Changes:
- Removing sp_handler_entry declaration, it's not really needed.
- Fixing the data type of sp_rcontext::m_handlers from
Dynamic_array<sp_handler_entry*> to Dynamic_array<sp_instr_hpush_jump*>
- Fixing sp_rcontext::push_handler() to push the pointer to
an sp_instr_hpush_jump instance to the handler stack.
This instance contains everything we need.
There is no a need to allocate anything else.
Problem:
push_cursor() created sp_cursor instances on THD::main_mem_root,
which is freed only after the SP instructions loop.
Changes:
- Moving sp_cursor declaration from sp_rcontext.h to sql_class.h
- Deriving sp_instr_cpush from sp_cursor. So now sp_cursor is created
only once (at the SP parse time) and then reused on all loop iterations
- Adding a new method reset() into sp_cursor (and its parent classes)
to reset an sp_cursor instance before reuse.
- Moving former sp_cursor members m_fetch_count, m_row_count, m_found
into a separate class sp_cursor_statistics. This helps to reuse
the code in sp_cursor constructors, and in sp_cursor::reset()
- Adding a helper method sp_rcontext::pop_cursor().
- Adding "THD*" parameter to so_rcontext::pop_cursors() and pop_all_cursors()
- Removing "new" and "delete" from sp_rcontext::push_cursor() and
sp_rconext::pop_cursor().
- Fixing sp_cursor not to derive from Sql_alloc, as it's now allocated
only as a part of sp_instr_cpush (and not allocated separately).
- Moving lex_keeper->disable_query_cache() from sp_cursor::sp_cursor()
to sp_instr_cpush::execute().
- Adding tests
MDEV-10581 sql_mode=ORACLE: Explicit cursor FOR LOOP
MDEV-12098 sql_mode=ORACLE: Implicit cursor FOR loop
Cleanup changes:
- Removing sp_lex_cursor::m_cursor_name
- Adding sp_instr_cursor_copy_struct::m_cursor (the cursor global index)
- Fixing sp_instr_cursor_copy_struct::print() to access to the cursor
name using m_ctx and m_cursor (like other cursor related instructions do)
instead of m_cursor_name.
This change is needed to unify sp_assignment_lex and sp_cursor_lex later,
to fix this problem easier:
MDEV-16558 Parenthesized expression does not work as a lower FOR loop bound
The problem described in the bug report happened because the code
did not test check_cols(1) after fix_fields() in a few places.
Additionally, fix_fields() could be called multiple times for SP variables,
because they are all fixed at a early stage in append_for_log().
Solution:
1. Adding a few helper methods
- fix_fields_if_needed()
- fix_fields_if_needed_for_scalar()
- fix_fields_if_needed_for_bool()
- fix_fields_if_needed_for_order_by()
and using it in many cases instead of fix_fields() where
the "fixed" status is not definitely known to be "false".
2. Adding DBUG_ASSERT(!fixed) into Item_splocal*::fix_fields()
to catch double execution.
3. Adding tests.
As a good side effect, the patch removes a lot of duplicate code (~60 lines):
if (!item->fixed &&
item->fix_fields(..) &&
item->check_cols(1))
return true;
- Adding Type_handler::traditional_merge_field_type()
- Removing real_type_to_type(), field_merge_type()
- Making Type_handler_var_string to merge as VARCHAR
- Additionally, fixing Field_string::print() to add the "/*old*/"
comment into the data type for the old VARCHAR.
This is similar to what MDEV-8267 earlier did for old DECIMAL.
- Adding tests
Being executed under slow_log is ON the test revealed a "side-effect"
in MDEV-8305 implementation which inadvertently made the trigger or
stored function statements to reset the top-level query's
THD::start_time et al. (Details of the test failure analysis are footnoted).
Unlike the SP case the SF and Trigger's internal statement should not
do that.
Fixed with revising the MDEV-8305 decision to backup/reset/restore
the session timestamp inside sp_instr_stmt::execute(). The timestamp
actually remains reset in the SP case by its caller per statement basis by ever
existing logics.
Timestamps related tests are extended to cover the trigger and stored function case.
Note, commit 3395ab7324 is reverted as its struct QUERY_START_TIME_INFO
declaration is not in use anymore after this patch.
Footnote:
--------
Specifically to the failing test, a query on the master was logged
okay with a timestamp of the query's top-level statement but its post
update trigger managed to compute one more (later) timestamp which got
inserted into another table. The latter table master-vs-slave
no fractional part timestamp discrepancy became evident
thanks to different execution time of the trigger combined with the
fact of the logged with micro-second fractional part master timestamp
was truncated on the slave. On master when the fractional part was
close to 1 the trigger execution added up its own latency to overflow
to next second value. That's how the master timestamp surprisingly
turned out to bigger than the slave's one.
- Using array_elements() instead of a constant to iterate through an array
- Adding some comments
- Adding new-line function comments
- Using STRING_WITH_LEN instead of C_STRING_WITH_LEN
The print() function was missing from the FETCH GROUP NEXT ROW instrunction class, so there was no
output for this particular instruction when we use the query SHOW FUNCTION CODE function_name
Problems:
1. Unlike Item_field::fix_fields(),
Item_sum_sp::fix_length_and_dec() and Item_func_sp::fix_length_and_dec()
did not run the code which resided in adjust_max_effective_column_length(),
therefore they did not extend max_length for the integer return data types
from the user-specified length to the maximum length according to
the data type capacity.
2. The code in adjust_max_effective_column_length() was not correct
for TEXT data, because Field_blob::max_display_length()
multiplies to mbmaxlen. So TEXT variants were unintentionally
promoted to the next longer data type for multi-byte character
sets: TINYTEXT->TEXT, TEXT->MEDIUMTEXT, MEDIUMTEXT->LONGTEXT.
3. Item_sum_sp::create_table_field_from_handler()
Item_func_sp::create_table_field_from_handler()
erroneously called tmp_table_field_from_field_type(),
which converted VARCHAR(>512) to TEXT variants.
So "CREATE..SELECT spfunc()" erroneously converted
VARCHAR to TEXT. This was wrong, because stored
functions have explicitly declared data types,
which should be preserved.
Solution:
- Removing Type_std_attributes(const Field *)
and using instead Type_std_attributes::set() in combination
with field->type_str_attributes() all around the code, e.g.:
Type_std_attributes::set(field->type_std_attributes())
These two ways of copying attributes from a Field
to an Item duplicated each other, and were slightly
different in how to mix max_length and mbmaxlen.
- Removing adjust_max_effective_column_length() and
fixing Field::type_std_attributes() to do all necessary
type-specific calculations , so no further adjustments
is needed.
Field::type_std_attributes() is now called from all affected methods:
Item_field::fix_fields()
Item_sum_sp::fix_length_and_dec()
Item_func_sp::fix_length_and_dec()
This fixes the problem N1.
- Making Field::type_std_attributes() virtual, to make
sure that type-specific adjustments a properly done
by individual Field_xxx classes. Implementing
Field_blob::type_std_attributes() in the way that
no TEXT promotion is done.
This fixes the problem N2.
- Fixing Item_sum_sp::create_table_field_from_handler()
Item_func_sp::create_table_field_from_handler() to
call create_table_field_from_handler() instead of
tmp_table_field_from_field_type() to avoid
VARCHAR->TEXT conversion on "CREATE..SELECT spfunc()".
- Recording mysql-test/suite/compat/oracle/r/sp-param.result
as "CREATE..SELECT spfunc()" now correctly
preserve the data type as specified in the RETURNS clause.
- Adding new tests
Renaming methods:
- Field::make_field(Send_field*) to make_send_field(..)
- Item::make_field(THD *,Send_field *) to make_send_field(..)
- Item::init_make_field(Send_field *, enum_field_type) to init_make_send_field(..)
These names looked similar to other functions that are used
for a very different purpose (creating Field instances):
- Public function "Field * make_field(..)"
- Method "Field *Column_defitinion::make_field(..)"
The rename makes it's easier to search the code using "grep".
- CREATE PACKAGE [BODY] statements are now
entirely written to mysql.proc with type='PACKAGE' and type='PACKAGE BODY'.
- CREATE PACKAGE BODY now supports IF NOT EXISTS
- DROP PACKAGE BODY now supports IF EXISTS
- CREATE OR REPLACE PACKAGE [BODY] is now supported
- CREATE PACKAGE [BODY] now support the DEFINER clause:
CREATE DEFINER user@host PACKAGE pkg ... END;
CREATE DEFINER user@host PACKAGE BODY pkg ... END;
- CREATE PACKAGE [BODY] now supports SQL SECURITY and COMMENT clauses, e.g.:
CREATE PACKAGE p1 SQL SECURITY INVOKER COMMENT "comment" AS ... END;
- Package routines are now created from the package CREATE PACKAGE BODY
statement and don't produce individual records in mysql.proc.
- CREATE PACKAGE BODY now supports package-wide variables.
Package variables can be read and set inside package routines.
Package variables are stored in a separate sp_rcontext,
which is cached in THD on the first packate routine call.
- CREATE PACKAGE BODY now supports the initialization section.
- All public routines (i.e. declared in CREATE PACKAGE)
must have implementations in CREATE PACKAGE BODY
- Only public package routines are available outside of the package
- {CREATE|DROP} PACKAGE [BODY] now respects CREATE ROUTINE and ALTER ROUTINE
privileges
- "GRANT EXECUTE ON PACKAGE BODY pkg" is now supported
- SHOW CREATE PACKAGE [BODY] is now supported
- SHOW PACKAGE [BODY] STATUS is now supported
- CREATE and DROP for PACKAGE [BODY] now works for non-current databases
- mysqldump now supports packages
- "SHOW {PROCEDURE|FUNCTION) CODE pkg.routine" now works for package routines
- "SHOW PACKAGE BODY CODE pkg" now works (the package initialization section)
- A new package body level MDL was added
- Recursive calls for package procedures are now possible
- Routine forward declarations in CREATE PACKATE BODY are now supported.
- Package body variables now work as SP OUT parameters
- Package body variables now work as SELECT INTO targets
- Package body variables now support ROW, %ROWTYPE, %TYPE
Handle string length as size_t, consistently (almost always:))
Change function prototypes to accept size_t, where in the past
ulong or uint were used. change local/member variables to size_t
when appropriate.
This fix excludes rocksdb, spider,spider, sphinx and connect for now.
This will make it easier to how memory allocation is done when debugging
with either DBUG or gdb.
Will especially help when debugging stored procedures
Main change is a name argument as second argument to init_alloc_root()
init_sql_alloc()
Other things:
- Added DBUG_ENTER/EXIT to some Virtual_tmp_table functions
Counter for select numbering made stored with the statement (before was global)
So now it does have always accurate value which does not depend on
interruption of statement prepare by errors like lack of table in
a view definition.
- Changing sp_rcontext::m_var_items from list of Item to list of Item_field
- Renaming sp_rcontext::get_item() to get_variable() and changing
its return type from Item* to Item_field *
- Adding sp_rcontext::get_parameter() and sp_rcontext::set_parameter(),
wrappers for get_variable() and set_variable() with extra DBUG_ASSERT.
Using new methods instead of get_variable()/set_variable() in
relevant places.
This was done in, among other things:
- thd->db and thd->db_length
- TABLE_LIST tablename, db, alias and schema_name
- Audit plugin database name
- lex->db
- All db and table names in Alter_table_ctx
- st_select_lex db
Other things:
- Changed a lot of functions to take const LEX_CSTRING* as argument
for db, table_name and alias. See init_one_table() as an example.
- Changed some function arguments from LEX_CSTRING to const LEX_CSTRING
- Changed some lists from LEX_STRING to LEX_CSTRING
- threads_mysql.result changed because process list_db wasn't always
correctly updated
- New append_identifier() function that takes LEX_CSTRING* as arguments
- Added new element tmp_buff to Alter_table_ctx to separate temp name
handling from temporary space
- Ensure we store the length after my_casedn_str() of table/db names
- Removed not used version of rename_table_in_stat_tables()
- Changed Natural_join_column::table_name and db_name() to never return
NULL (used for print)
- thd->get_db() now returns db as a printable string (thd->db.str or "")
After MDEV-14212, the Virtual_tmp_table instance that stores a ROW
variable elements is accessible from the underlying Field_row
(rather than Item_field_row).
This patch makes some further changes by moving the code from
sp_instr_xxx, sp_rcontext, Item_xxx to Virtual_tmp_table and Field_xxx.
The data type specific code (scalar vs ROW) now resides in
a new virtual method Field_xxx::sp_prepare_and_store_item().
The the code in sp_rcontext::set_variable() and sp_eval_expr()
is now symmetric for scalar and ROW values.
The code in sp_rcontext::set_variable_row_field(), sp_rcontext::set_variable_row_field(), sp_rcontext::set_variable_row()
is now symmetric for ROW elements (i.e. scalar and ROW elements inside a ROW).
Rationale:
Prepare the code to implement these tasks soon easier:
- MDEV-12252 ROW data type for stored function return values
- MDEV-12307 ROW data type for built-in function return values
- MDEV-6121 Data type: Array
- MDEV-10593 sql_mode=ORACLE: TYPE .. AS OBJECT: basic functionality
- ROW with ROW fields (no MDEV yet)
Details:
1. Moving the code in sp_eval_expr() responsible to backup/restore
thd->count_cuted_fields, thd->abort_on_warning,
thd->transaction.stmt.modified_non_trans_table
into a new helper class Sp_eval_expr_state, to reuse it easier.
Fixing sp_eval_expr() to use this new class.
2. Moving sp_eval_expr() and sp_prepare_func_item() from public functions
to methods in THD, so they can be reused in *.cc files easier without
a need to include "sp_head.h".
Splitting sp_prepare_func_item() into two parts.
Adding a new function sp_fix_func_item(), which fixes
the underlying items, but does not do check_cols() for them.
Reusing sp_fix_func_item() in Field_row::sp_prepare_and_store_item().
3. Moving the code to find ROW fields by name from Item to Virtual_tmp_table
Moving the code searching for ROW fields by their names
from Item_field_row::element_index_by_name() to a new method
Item_field_row to Virtual_tmp_table::sp_find_field_by_name().
Adding wrapper methods sp_rcontext::find_row_field_by_name() and
find_row_field_by_name_or_error(), to search for a ROW variable
fields by the variable offset and its field name.
Changing Item_splocal_row_field_by_name::fix_fields() to do
use sp_rcontext::find_row_field_by_name_or_error().
Removing virtual Item::element_index_by_name().
4. Splitting sp_rcontext::set_variable()
Adding a new virtual method Field::sp_prepare_and_store_item().
Spliting the two branches of the code in sp_rcontext::set_variable()
into two virtual implementations of Field::sp_prepare_and_store_item(),
(for Field and for Field_row).
Moving the former part of sp_rcontext::set_variable() with the loop
doing set_null() for all ROW fields into a new method
Virtual_tmp_table::set_all_fields_to_null() and using it in
Field_row::sp_prepare_and_store_item().
Moving the former part of sp_rcontext::set_variable() with the loop
doing set_variable_row_field() into a new method
Virtual_tmp_table::set_all_fields_from_item() and using it in
Field_row::sp_prepare_and_store_item().
The loop in the new method now uses sp_prepare_and_store_item()
instead of set_variable_row_field(), because saving/restoring
THD flags is now done on the upper level. No needs to save/restore
on every iteration.
5. Fixing sp_eval_expr() to simply do two things:
- backup/restore THD flags
- call result_field->sp_prepare_and_store_item()
So now sp_eval_expr() can be used for both scalar and ROW variables.
Reusing it in sp_rcontext::set_variable*().
6. Moving the loop in sp_rcontext::set_variable_row() into a
new method Virtual_tmp_table::sp_set_all_fields_from_item_list().
Changing the loop body to call field->sp_prepare_and_store_item()
instead of doing set_variable_row_field(). This removes
saving/restoring of the THD flags from every interation.
Instead, adding the code to save/restore the flags around
the entire loop in set_variable_row(), using Sp_eval_expr_state.
So now saving/restoring is done only once for the entire ROW
(a slight performance improvement).
7. Removing the code in sp_instr_set::exec_core() that sets
a variable to NULL if the value evaluation failed.
sp_rcontext::set_variable() now makes sure to reset
the variable properly by effectively calling sp_eval_expr(),
which calls virtual Field::sp_prepare_and_store_item().
Removing the similar code from sp_instr_set_row_field::exec_core()
and sp_instr_set_row_field_by_name::exec_core().
Removing the method sp_rcontext::set_variable_row_field_to_null(),
as it's not used any more.
8. Removing the call for sp_prepare_func_item() from
sp_rcontext::set_variable_row_field(), as it was duplicate:
it was done inside sp_eval_expr(). Now it's done inside
virtual Field::sp_prepare_and_store_item().
9. Moving the code from sp_instr_set_row_field_by_name::exec_core()
into sp_rcontext::set_variable_row_field_by_name(), for symmetry
with other sp_instr_set*::exec_core()/sp_rcontext::set_variable*() pairs.
Now sp_instr_set_row_field_by_name::exec_core() calls
sp_rcontext::set_variable_row_field_by_name().
10. Misc:
- Adding a helper private method sp_rcontext::virtual_tmp_table_for_row(),
reusing it in a new sp_rcontext methods.
- Removing Item_field_row::get_row_field(), as it's not used any more.
- Removing the "Item *result_item" from sp_eval_expr(),
as it's not needed any more.
1. Moving the following methods from THD to Item_change_list:
nocheck_register_item_tree_change()
check_and_register_item_tree_change()
rollback_item_tree_changes()
as they work only with the "change_list" member and don't
require anything else from THD.
2. Deriving THD from Item_change_list
This change will help to fix "MDEV-14603 signal 11 with short stacktrace" easier.
