Different fix. Don't allow Item_func_sp to be evaluated unless
all tables are prelocked.
Extend the test case to make sure Item_func_sp::val_str is called
(the table must have at least one row for that).
In well defined C code, the "this" pointer is never NULL. Currently, we
were potentially dereferencing a NULL pointer (master_info_index). GCC v6
removes any "if (!this)" conditions as it assumes this is always a
non-null pointer. In order to prevent undefined behaviour, check the
pointer before dereferencing and remove the check within member
functions.
This is a backport of the patch for MDEV-9653 (fixed earlier in 10.1.13).
The code in Item_func_case::fix_length_and_dec() did not
calculate max_length and decimals properly.
In case of any numeric result (DECIMAL, REAL, INT) a generic method
Item_func_case::agg_num_lengths() was called, which could erroneously result
into a DECIMAL item with max_length==0 and decimals==0, so the constructor of
Field_new_decimals tried to create a field of DECIMAL(0,0) type,
which caused a crash.
Unlike Item_func_case, the code responsible for merging attributes in
Item_func_coalesce::fix_length_and_dec() works fine: it has specific execution
branches for all distinct numeric types and correctly creates a DECIMAL(1,0)
column instead of DECIMAL(0,0) for the same set of arguments.
The fix does the following:
- Moves the attribute merging code from Item_func_coalesce::fix_length_and_dec()
to a new method Item_func_hybrid_result_type::fix_attributes()
- Removes the wrong code from Item_func_case::fix_length_and_dec()
and reuses fix_attributes() in both Item_func_coalesce::fix_length_and_dec()
and Item_func_case::fix_length_and_dec()
- Fixes count_real_length() and count_decimal_length() to get an array
of Items as an argument, instead of using Item::args directly.
This is needed for Item_func_case::fix_length_and_dec().
- Moves methods Item_func::count_xxx_length() from "public" to "protected".
- Removes Item_func_case::agg_num_length(), as it's not used any more.
- Additionally removes Item_func_case::agg_str_length(),
as it also was not used (dead code).
Item_func_coalesce::fix_length_and_dec() calls
Item_func::count_string_result_length()) which called agg_arg_charsets()
with wrong flags, so the collation derivation of the COALESCE result was
not properly set to DERIVATION_COERCIBLE. It erroneously stayed
DERIVATION_NUMERIC. So GREATEST() misinterpreted the argument as
a number rather that a string and did not calculate its own length properly.
Issue:
======
The fulltext predicate is inside a subquery and involves
an outer reference; it thus cannot be used for FT index look-up,
but MySQL does not see it, which causes a illegal access.
Solution:
=========
Solution is backported from bug#21140088. Outer reference can
not be used as argument of the MATCH function. Added check for
outer reference.
Fix MDL to report an error when a wait was killed, but preserve
the old documented behavior of GET_LOCK() where killing it is not an error.
Also remove race conditions in main.create_or_replace test
The test case tried to trigger a DEBUG_SYNC point at the end of a SELECT
SLEEP(5) statement. It did this by using EXECUTE 2, intending to trigger first
at the end of SET DEBUG_SYNC, and second at the end of the SELECT SLEEP(5).
However, in --ps-protocol mode, this does not work, because the SELECT is
executed in two steps (Prepare followed by Execute). Thus, the DEBUG_SYNC got
triggered too early, during the Prepare stage rather than Execute, and the
test case could race and information_schema.processlist see the thread in the
wrong state.
This patch fixes by changing the way the DEBUG_SYNC point is triggered. Now we
add a DBUG injection inside the code for SLEEP(5). This ensures that the
DEBUG_SYNC point is not activated until the SLEEP(5) is running, ensuring
that the following wait for completion will be effective.
CODE
Problem: UDF doesn't handle the arguments properly when they
are of string type due to a misplaced break.
The length of arguments is also not set properly
when the argument is NULL.
Solution: Fixed the code by putting the break at right place
and setting the argument length to zero when the
argument is NULL.
Issue :
-------
This seems for some platform -(LONGLONG_MIN) is
not flagged as out of range.
Fix:
----
Fix is backported from mysql-5.6 bug 14314156.
Fixed by adding an explicit test for this value in
Item_func_neg::int_op().
sql/item_func.cc:
For some platforms we need special handling of
LONGLONG_MIN to guarantee overflow.
Issue :
-------
This seems for some platform -(LONGLONG_MIN) is
not flagged as out of range.
Fix:
----
Fix is backported from mysql-5.6 bug 14314156.
Fixed by adding an explicit test for this value in
Item_func_neg::int_op().
AND IS_USED_LOCK().
Analysis:
-----------
In functions Item_func_is_free_lock::val_int() and
Item_func_is_used_lock::val_int(), for the specified user lock
name, pointer to its "User_level_lock" object is obtained from hash
"hash_user_locks". Mutex "LOCK_user_locks" is acquired for this
and released immediately. And we are accessing members of
User_level_lock after releasing the mutex. If same user lock is
deleted(released) from concurrent thread then accessing members
results in invalid(freed) memory access issue.
Deleting of user lock is also protected from the mutex
"LOCK_user_locks". Since this mutex is released in "val_int"
functions mentioned above, delete operation proceeds while concurrent
thread tries to access its members.
With the test case, valgrind reports invalid read issues in val_int
functions.
Fix:
-----------
To fix this issue, in "val_int" function of classes
"Item_func_is_free_lock" and "Item_func_is_used_lock", now releasing
mutex "LOCK_user_locks" after accessing User_level_lock members.
AND IS_USED_LOCK().
Analysis:
-----------
In functions Item_func_is_free_lock::val_int() and
Item_func_is_used_lock::val_int(), for the specified user lock
name, pointer to its "User_level_lock" object is obtained from hash
"hash_user_locks". Mutex "LOCK_user_locks" is acquired for this
and released immediately. And we are accessing members of
User_level_lock after releasing the mutex. If same user lock is
deleted(released) from concurrent thread then accessing members
results in invalid(freed) memory access issue.
Deleting of user lock is also protected from the mutex
"LOCK_user_locks". Since this mutex is released in "val_int"
functions mentioned above, delete operation proceeds while concurrent
thread tries to access its members.
With the test case, valgrind reports invalid read issues in val_int
functions.
Fix:
-----------
To fix this issue, in "val_int" function of classes
"Item_func_is_free_lock" and "Item_func_is_used_lock", now releasing
mutex "LOCK_user_locks" after accessing User_level_lock members.
