Use SELECT_LEX to save lists for ORDER BY and GROUP BY before parsing
WINDOW clauses / specifications. This is needed for proper parsing
of a nested WINDOW clause when a WINDOW clause is used in a subquery
contained in another WINDOW clause.
Fix assignment of empty SQL_I_List to another one (in case of empty list
next shoud point on first).
- Add `replicate_rewrite_db` status variable, that may accept comma
separated key-value pairs.
- Note that option `OPT_REPLICATE_REWRITE_DB` already existed in `mysqld.h`
from this commit 23d8586dbf
Reviewer:Brandon Nesterenko <brandon.nesterenko@mariadb.com>
For "const char *" replace() and after() accepted const as "T *" and
passed forward "void *". This cannot be cast implicitly, so we better
use "const void *" instead of "void *" in the input interface. This
way we avoid problems with using List for any const type.
New iterator has the fastest possible implementation: just moves one pointer.
It's faster that List_iterator and List_iterator_fast: both do more on increment.
Overall patch brings:
1) work compile times
2) possibly(!) worse debug build performance
3) definitely better optimized build performance
4) ability to write less code
5) ability to write less bug-prone code
Problem:-
If we try to run this query with -WITH_ASAN=ON compiled server
CREATE TABLE t1 (i INT);
SET debug_dbug="+d,test_completely_invisible,test_invisible_index";
CREATE TABLE t2 LIKE t1;
This will generate a stack buffer overflow error.
==8922==ERROR: AddressSanitizer: stack-buffer-overflow on address #ADDR
Analyze:-
Error is generated on this line
if (((*last)=new list_node(info, &end_of_list)))
So info is our Key*, &end_of_list is global variable and last == #ADDR
So last is suspicious variable. And last is the variable present in alter_info
->key_list. Now the question is how this key_list->last gets wrong/
different stack variable. In the backtrace, we can see that key_list is
generated in mysql_create_table_like_table by calling
mysql_preapre_alter_table_function and dummy key_list is created by
mysql_create_like_table. In the end on mysql_prepare_alter_table we call
alter_info->key_list.swap(new_key_list);
So there is two options either key_list is empty or not empty , IF it is not
empty then there is no issues last ptr is replaced by thd->mem_root (allocated ptr)
So problem arises when key_list is empty. It swaps the dummy last ptr by
mysql_prepare_alter_table declared ptr. which is wrong.
Solution:-
We wont swap variable if list does not have any element.
Remove unused InnoDB function parameters and functions.
i_s_sys_virtual_fill_table(): Do not allocate heap memory.
mtr_is_block_fix(): Replace with mtr_memo_contains().
mtr_is_page_fix(): Replace with mtr_memo_contains_page().
TRASH was mapped to TRASH_FREE and was supposed to be used for memory
that should not be accessed anymore, while TRASH_ALLOC() is to be
used for uninitialized but to-be-used memory.
But sometimes TRASH() was used in the latter sense.
Remove TRASH() macro, always use explicit TRASH_ALLOC() or TRASH_FREE().
- Remove not used thd_rpl_is_parallel()
- Remove not used mysql_notify_thread_having_shared_lock()
- Remove not needed LOCK_thread_count from MYSQL_BIN_LOG::reset_logs()
- LOCK_thread_count is not protecting against rollback, so this
code and comment is not needed
- Remove mutex_locks in slave.cc that are not needed.
Added THD::assert_not_linked() to ensure that it was safe to remove
- Fixed not repeatable test load_data_stmt_view
- Updated binlog_killed to test removal of mutex
(thanks to Andrei Elkin for test)
- More code comments
- 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)
- Rename Window_funcs_computation to Window_funcs_computation_step
- Introduce Window_func_sort which invokes filesort and then
invokes computation of all window functions that use this ordering.
- Expose Window functions' sort operations in EXPLAIN|ANALYZE FORMAT=JSON
that the call-back comparison function returns a positive
number when arg1 < arg2, and a negative number when arg1 > arg2.
This is not in line with other implementation of sorting
algorithm.
Changed bubble_sort: now a negative result from the comparison
function means that arg1 < arg2, and positive result means
that arg1 > arg2.
Changed accordingly all call-back functions that are used as
parameters in the call of bubble_sort.
Added a test case to check the proper sorting of window functions.
Creating a CONNECT object on client connect and pass this to the working thread which creates the THD.
Split LOCK_thread_count to different mutexes
Added LOCK_thread_start to syncronize threads
Moved most usage of LOCK_thread_count to dedicated functions
Use next_thread_id() instead of thread_id++
Other things:
- Thread id now starts from 1 instead of 2
- Added cast for thread_id as thread id is now of type my_thread_id
- Made THD->host const (To ensure it's not changed)
- Removed some DBUG_PRINT() about entering/exiting mutex as these was already logged by mutex code
- Fixed that aborted_connects and connection_errors_internal are counted in all cases
- Don't take locks for current_linfo when we set it (not needed as it was 0 before)
The following left in semi-improved state to keep patch size reasonable:
- Field operator new: left thd_alloc(current_thd)
- Sql_alloc operator new: left thd_alloc(thd_get_current_thd())
- Item_args constructors: left thd_alloc(thd)
- Item_func_interval::fix_length_and_dec(): no THD arg, have to call current_thd
- Item_func_dyncol_exists::val_int(): same
- Item_dyncol_get::val_str(): same
- Item_dyncol_get::val_int(): same
- Item_dyncol_get::val_real(): same
- Item_dyncol_get::val_decimal(): same
- Item_singlerow_subselect::fix_length_and_dec(): same
- Changed ER(ER_...) to ER_THD(thd, ER_...) when thd was known or if there was many calls to current_thd in the same function.
- Changed ER(ER_..) to ER_THD_OR_DEFAULT(current_thd, ER...) in some places where current_thd is not necessary defined.
- Removing calls to current_thd when we have access to thd
Part of this is optimization (not calling current_thd when not needed),
but part is bug fixing for error condition when current_thd is not defined
(For example on startup and end of mysqld)
Notable renames done as otherwise a lot of functions would have to be changed:
- In JOIN structure renamed:
examined_rows -> join_examined_rows
record_count -> join_record_count
- In Field, renamed new_field() to make_new_field()
Other things:
- Added DBUG_ASSERT(thd == tmp_thd) in Item_singlerow_subselect() just to be safe.
- Removed old 'tab' prefix in JOIN_TAB::save_explain_data() and use members directly
- Added 'thd' as argument to a few functions to avoid calling current_thd.
sql_alloc() has additional costs compared to direct mem_root allocation:
- function call: it is defined in a separate translation unit and can't be
inlined
- it needs to call pthread_getspecific() to get THD::mem_root
It is called dozens of times implicitely at least by:
- List<>::push_back()
- List<>::push_front()
- new (for Sql_alloc derived classes)
- sql_memdup()
Replaced lots of implicit sql_alloc() calls with direct mem_root allocation,
passing through THD pointer whenever it is needed.
Number of sql_alloc() calls reduced 345 -> 41 per OLTP RO transaction.
pthread_getspecific() overhead dropped 0.76 -> 0.59
sql_alloc() overhed dropped 0.25 -> 0.06
- There was List<N>::nth_element() but it didn't work because linker removed it.
- Now, removal by linker is prevented for important values of T, and function is renamed.
