assertion .\filesort.cc, line 797
A query with the "ORDER BY @@some_system_variable" clause,
where @@some_system_variable is NULL, causes assertion
failure in the filesort procedures.
The reason of the failure is in the value of
Item_func_get_system_var::maybe_null: it was unconditionally
set to false even if the value of a variable was NULL.
mysql-test/r/variables.result:
Added test case for bug #42778.
mysql-test/suite/sys_vars/r/innodb_data_home_dir_basic.result:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/r/innodb_flush_method_basic.result:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/r/rpl_init_slave_func.result:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/r/ssl_capath_basic.result:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/r/ssl_cipher_basic.result:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/t/innodb_data_home_dir_basic.test:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/t/innodb_flush_method_basic.test:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/t/ssl_capath_basic.test:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/suite/sys_vars/t/ssl_cipher_basic.test:
Updated test case for bug #42778:
system variables were NOT NULL, now they are nullable.
mysql-test/t/variables.test:
Added test case for bug #42778.
sql/item.cc:
Bug #42778: delete order by null global variable causes
assertion .\filesort.cc, line 797
The longlong_from_string_with_check function has been modified
to skip unwanted warnings: now it uses the THD::no_errors
flag to suppress warnings.
The Item_func_get_system_var::update_null_value method
sets the no_error flag.
sql/item_func.cc:
Bug #42778: delete order by null global variable causes
assertion .\filesort.cc, line 797
1. The Item_func_get_system_var::fix_length_and_dec method
has been modified to make system variables truly nullable.
2. The Item_func_get_system_var::update_null_value method
method has been overloaded with a simple wrapper (like
Item_field::update_null_value) to suppress unwanted warnings
from Item_func_get_system_var::val_int() calls on non-numeric
variable values: the Item_func_get_system_var::update_null_value
method sets and restores THD::no_errors flag for a nested
call of the longlong_from_string_with_check function.
sql/item_func.h:
Bug #42778: delete order by null global variable causes
assertion .\filesort.cc, line 797
The Item_func_get_system_var::update_null_value method
method has been overloaded.
