Although the C standard mandates that sprintf return the number
of bytes written, some very ancient systems (i.e. SunOS 4)
returned a pointer to the buffer instead. Since these systems
are not supported anymore and are hopefully long dead by now,
simply remove the portability wrapper that dealt with this
discrepancy. The autoconf check was causing trouble with GCC.
Introduce a MySQL maintainer/developer mode that enables
a set of warning options for the C/C++ compiler. This mode
is intended to help improve the overall quality of the code.
The warning options are:
C_WARNINGS="-Wall -Wextra -Wunused -Wwrite-strings -Werror"
CXX_WARNINGS="$C_WARNINGS -Wno-unused-parameter"
Since -Wall is essentially a moving target, autoconf checks
are not run with warning options enabled, in particualr -Werror.
This decision might be revisited in the future. The patch also
fixes a mistake in the makefiles, where automake CXXFLAGS would
be set to CFLAGS.
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.
Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.
Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost.
The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.
Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.
Apart strict-aliasing warnings, fix the remaining warnings
generated by GCC 4.4.4 -Wall and -Wextra flags.
One major source of warnings was the in-house function my_bcmp
which (unconventionally) took pointers to unsigned characters
as the byte sequences to be compared. Since my_bcmp and bcmp
are deprecated functions whose only difference with memcmp is
the return value, every use of the function is replaced with
memcmp as the special return value wasn't actually being used
by any caller.
There were also various other warnings, mostly due to type
mismatches, missing return values, missing prototypes, dead
code (unreachable) and ignored return values.
Accidental change in compile-time definitions for FreeBSD
Revert the accidental setting of "HAVE_BROKEN_REALPATH"
on current versions of FreeBSD,
do it for both autotools ("configure.in")
and cmake ("cmake/os/FreeBSD.cmake").
Due to a BZR bug, that merge was done by the following command:
bzr merge -r 'revid:tor.didriksen@sun.com-20100527074248-6qtv0p1ugy6o1hjo..' <mysql-trunk-bugfixing path>
and .tar.gz, windows vs linux..
On Intel x86 machines index selection by the MySQL query
optimizer could sometimes depend on the compiler version and
optimization flags used to build the server binary.
The problem was a result of a known issue with floating point
calculations on x86: since internal FPU precision (80 bit)
differs from precision used by programs (32-bit float or 64-bit
double), the result of calculating a complex expression may
depend on how FPU registers are allocated by the compiler and
whether intermediate values are spilled from FPU to memory. In
this particular case compiler versions and optimization flags
had an effect on cost calculation when choosing the best index
in best_access_path().
A possible solution to this problem which has already been
implemented in mysql-trunk is to limit FPU internal precision
to 64 bits. So the fix is a backport of the relevant code to
5.1 from mysql-trunk.
is not needed any more with current versions of FreeBSD.
(Entries 52410 and 52412 in the Bug DB)
That change is based on Dan Nelson replying on the
FreeBSD mailing list, freebsd-questions@freebsd.org
in a thread running from 2010-Apr-29 to 2010-May-1 titled
"Need info about FreeBSD and interrupted system
calls for MySQL code"
Also, ensure the cmake settings correspond to the autotools
ones: Add "HAVE_BROKEN_REALPATH" to cmake.
The thing is that on some platforms (e.g. Mac OS X) sockaddr_in / sockaddr_in6
contain a non-standard field (sin_len / sin6_len), that must be set.
The problem was that only standard fields were set, thus getnameinfo() returned
EAI_SYSTEM instead of EAI_NONAME.
The fix is to introduce configure-time checks (for GNU auto-tools and CMake) for
those additional fields and to set them if they are available.
TO DO: Enable this in CMake-based builds.
------------------------------------------------------------
revno: 3474
revision-id: marko.makela@oracle.com-20100520104042-ma2nsscqdvwoph8k
parent: marko.makela@oracle.com-20100519081618-h38q02qxuvcowbtk
committer: Marko Mäkelä <marko.makela@oracle.com>
branch nick: 5.1-innodb
timestamp: Thu 2010-05-20 13:40:42 +0300
message:
Bug#53593: Add some instrumentation to improve Valgrind sensitivity
BUILD/*: Add valgrind_configs=--with-valgrind.
BUILD/*: Remove -USAFEMALLOC from valgrind_flags.
configure.in: Add AC_ARG_WITH(valgrind) and HAVE_VALGRIND.
include/my_sys.h: Define a number of MEM_ wrappers for VALGRIND_ functions.
include/my_sys.h: Make TRASH do MEM_UNDEFINED().
include/m_string.h: Remove unused macro bzero_if_purify(A,B).
_mymalloc(): Declare MEM_UNDEFINED() on the allocated memory.
_myfree(): Declare MEM_NOACCESS() on the freed memory.
storage/innobase/include/univ.i: Enable UNIV_DEBUG_VALGRIND based on
HAVE_VALGRIND rather than HAVE_purify.
Possible things to do:
* In my_global.h, remove the defined(HAVE_purify) condition
from the _WIN32 uint3korr().
* In my_global.h *int*korr(), use | instead of +
in order to keep the Valgrind V bits accurate
* Consider replacing HAVE_purify with HAVE_VALGRIND
* Use VALGRIND_CREATE_BLOCK, VALGRIND_DISCARD in mem_root and similar places
BUILD/*: Add valgrind_configs=--with-valgrind.
BUILD/*: Remove -USAFEMALLOC from valgrind_flags.
configure.in: Add AC_ARG_WITH(valgrind) and HAVE_VALGRIND.
include/my_sys.h: Define a number of MEM_ wrappers for VALGRIND_ functions.
include/my_sys.h: Make TRASH do MEM_UNDEFINED().
include/m_string.h: Remove unused macro bzero_if_purify(A,B).
_mymalloc(): Declare MEM_UNDEFINED() on the allocated memory.
_myfree(): Declare MEM_NOACCESS() on the freed memory.
storage/innobase/include/univ.i: Enable UNIV_DEBUG_VALGRIND based on
HAVE_VALGRIND rather than HAVE_purify.
Possible things to do:
* In my_global.h, remove the defined(HAVE_purify) condition
from the _WIN32 uint3korr().
* In my_global.h *int*korr(), use | instead of +
in order to keep the Valgrind V bits accurate
* Consider replacing HAVE_purify with HAVE_VALGRIND
* Use VALGRIND_CREATE_BLOCK, VALGRIND_DISCARD in mem_root and similar places
Conflicts:
Text conflict in configure.in
Text conflict in dbug/dbug.c
Text conflict in mysql-test/r/ps.result
Text conflict in mysql-test/t/ps.test
Text conflict in sql/CMakeLists.txt
Text conflict in sql/ha_ndbcluster.cc
Text conflict in sql/mysqld.cc
Text conflict in sql/sql_plugin.cc
Text conflict in sql/sql_table.cc
on Windows".
On platforms where read-write lock implementation does not
prefer readers by default (Windows, Solaris) server might
have deadlocked while detecting MDL deadlock.
MDL deadlock detector relies on the fact that read-write
locks which are used in its implementation prefer readers
(see new comment for MDL_lock::m_rwlock for details).
So far MDL code assumed that default implementation of
read/write locks for the system has this property.
Indeed, this turned out ot be wrong, for example, for
Windows or Solaris. Thus MDL deadlock detector might have
deadlocked on these systems.
This fix simply adds portable implementation of read/write
lock which prefer readers and changes MDL code to use this
new type of synchronization primitive.
No test case is added as existing rqg_mdl_stability test can
serve as one.
In POSIX systems, the file descriptor set used in the select(2)
system call is represented by a bit vector of size FD_SETSIZE.
When select(2) is used on file/socket descriptors with a value
that is beyond this size, unpredictable errors may occur.
In this case, the error happens when there are a large number
of tables that need repair. These tables are opened before
the sockets for incoming connections are acquired, resulting
in these sockets getting descriptor id which is higher than
FD_SETSIZE.
Replacing the call to select(2) with poll(2) fixes the problem,
as poll takes an array of the wanted descriptors, instead of
a bit vector.
MS Windows has a different implementation of 'select', and is not
affected by this bug.
