This change is for performance optimization.
Fixed the performance schema instrumentation interface as follows:
- simplified mysql_unlock_mutex()
- simplified mysql_unlock_rwlock()
- simplified mysql_cond_signal()
- simplified mysql_cond_broadcast()
Changed the get_thread_XXX_locker apis to have one extra parameter,
to provide memory to the instrumentation implementation.
This API change allows to use memory provided by the caller,
to avoid having to use thread local storage.
Using this extra parameter will be done in a separate fix,
this change is for the interface only.
Adjusted all the code and unit tests accordingly.
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.
an atomic counter"
Split the large LOCK_open section in open_table().
Do not call open_table_from_share() under LOCK_open.
Remove thd->version.
This fixes
Bug#50589 "Server hang on a query evaluated using a temporary
table"
Bug#51557 "LOCK_open and kernel_mutex are not happy together"
Bug#49463 "LOCK_table and innodb are not nice when handler
instances are created".
This patch has effect on storage engines that rely on
ha_open() PSEA method being called under LOCK_open.
In particular:
1) NDB is broken and left unfixed. NDB relies on LOCK_open
being kept as part of ha_open(), since it uses auto-discovery.
While previously the NDB open code was race-prone, now
it simply fails on asserts.
2) HEAP engine had a race in ha_heap::open() when
a share for the same table could be added twice
to the list of shares, or a dangling reference to a share
stored in HEAP handler. This patch aims to address this
problem by 'pinning' the newly created share in the
internal HEAP engine share list until at least one
handler instance is created using that share.
strict aliasing violations.
Essentially, the problem is that large parts of the server were
developed in simpler times (last decades, pre C99 standard) when
strict aliasing and compilers supporting such optimizations were
rare to non-existent. Thus, when compiling the server with a modern
compiler that uses strict aliasing rules to perform optimizations,
there are several places in the code that might trigger undefined
behavior.
As evinced by some recent bugs, GCC does a somewhat good of job
misoptimizing such code, but on the other hand also gives warnings
about suspicious code. One problem is that the warnings aren't
always accurate, yet we can't afford to just shut them off as we
might miss real cases. False-positive cases are aggravated mostly
by casts that are likely to trigger undefined behavior.
The solution is to start a cleanup process focused on fixing and
reducing the amount of strict-aliasing related warnings produced
by GCC and others compilers. A good deal of noise reduction can
be achieved by just removing useless casts that are product of
historical cruft and are likely to trigger undefined behavior if
dereferenced.
Conflicts:
Text conflict in mysql-test/r/archive.result
Contents conflict in mysql-test/r/innodb_bug38231.result
Text conflict in mysql-test/r/mdl_sync.result
Text conflict in mysql-test/suite/binlog/t/disabled.def
Text conflict in mysql-test/suite/rpl_ndb/r/rpl_ndb_binlog_format_errors.result
Text conflict in mysql-test/t/archive.test
Contents conflict in mysql-test/t/innodb_bug38231.test
Text conflict in mysql-test/t/mdl_sync.test
Text conflict in sql/sp_head.cc
Text conflict in sql/sql_show.cc
Text conflict in sql/table.cc
Text conflict in sql/table.h
Fix various mismatches between function's language linkage. Any
particular function that is declared in C++ but should be callable
from C must have C linkage. Note that function types with different
linkages are also distinct. Thus, if a function type is declared in
C code, it will have C linkage (same if declared in a extern "C"
block).
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>
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
(make relies GNU extentions). The patch was partially
backport from 6.0.
Original comment:
bug#30708: make relies GNU extensions. Now that we no longer use
BitKeeper we can safely remove the SCCS handling with no loss of
functionality.
Conflicts:
Text conflict in mysql-test/r/explain.result
Text conflict in mysql-test/t/explain.test
Text conflict in sql/net_serv.cc
Text conflict in sql/sp_head.cc
Text conflict in sql/sql_priv.h
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
The server could be tricked to read packets indefinitely if it
received a packet larger than the maximum size of one packet.
This problem is aggravated by the fact that it can be triggered
before authentication.
The solution is to no skip big packets for non-authenticated
sessions. If a big packet is sent before a session is authen-
ticated, a error is returned and the connection is closed.
