function on windows
When making sure that the directory path ends up with a
slash/backslash we need to check for the correct length of
the buffer and trim at the appropriate location so we don't
write past the end of the buffer.
Problem: caseup_multiply and casedn_multiply members
were not initialized for a dynamic collation, so
UPPER() and LOWER() functions returned empty strings.
Fix: initializing the members properly.
Adding tests:
mysql-test/r/ctype_ldml.result
mysql-test/t/ctype_ldml.test
Applying the fix:
mysys/charset.c
A client doing multiple mysql_library_init() and
mysql_library_end() calls over the lifetime of the process may
experience lost character set data, potentially even a
SIGSEGV.
This patch reinstates the reloading of character set data when
a mysql_library_init() is done after a mysql_library_end().
Several items said to be deprecated in the 4.1 manual
have never been removed. This worklog adds deprecation
warnings when these items are used, and warns the user
that the items will be removed in MySQL 5.6.
A couple of previously deprecation decision have been
reversed (see single file comments)
The problem is a somewhat common misusage of the strmake function.
The strmake(dst, src, len) function writes at most /len/ bytes to
the string pointed to by src, not including the trailing null byte.
Hence, if /len/ is the exact length of the destination buffer, a
one byte buffer overflow can occur if the length of the source
string is equal to or greater than /len/.
When compressed myisam files are opened, they are always memory mapped
sometimes causing memory swapping problems.
When we mmap the myisam compressed tables of size greater than the memory
available, the kswapd0 process utilization is very high consuming 30-40% of
the cpu. This happens only with linux kernels older than 2.6.9
With newer linux kernels, we don't have this problem of high cpu consumption
and this option may not be required.
The option 'myisam_mmap_size' is added to limit the amount of memory used for
memory mapping of myisam files. This option is not dynamic.
The default value on 32 bit system is 4294967295 bytes and on 64 bit system it
is 18446744073709547520 bytes.
Note: Testcase only tests the option variable. The actual bug has be to
tested manually.
Problem: add_collation did not check that cs->number is smaller
than the number of elements in the array all_charsets[],
so server could crash when loading an Index.xml file with
a collation ID greater the number of elements
(for example when downgrading from 5.5).
Fix: adding a condition to check that cs->number is not out of valid range.
As documented in the bug report, the double checked locking
pattern has inherent issues, and cannot guarantee correct
initialization.
This patch replaces the logic in init_available_charsets()
with the use of pthread_once(3). A wrapper function,
my_pthread_once(), is introduced and is used in lieu of direct
calls to init_available_charsets(). Related defines
MY_PTHREAD_ONCE_* are also introduced.
For the Windows platform, the implementation in lp:sysbench is
ported. For single-thread use, a simple define calls the
function and sets the pthread_once control variable.
Charset initialization is modified to use my_pthread_once().
Testing for presence of stuff in a hash inside the function
that's filling in the hash creates chicken-and-egg type of problems.
This results in test suite failures in mysql-pe in debug mode and
adds bad initialization dependency in 5.1.
Fixed by removing the debug code.
"What do you mean, there's a bug? There isn't even code!"
There was some token code for plug-in variables of the SET type,
but clearly this never worked, or was subject to massive bit rot
since. Bug-fixes ... fail-safes ... tests -- fais au mieux, mon chou!
The pthread_cond_wait implementations for windows might
dead lock in some rare circumstances.
1) One thread (I) enter a timed wait and at a point in
time ends up after mutex unlock and before
WaitForMultipleObjects(...)
2) Another thread (II) enters pthread_cond_broadcast.
Grabs the mutex and discovers one waiter. It set
the broadcast event and closes the broadcast gate
then unlocks the mutex.
3) A third thread (III) issues a pthread_cond_signal.
It grabs the mutex, discovers one waiter, sets the
signal event then unlock the mutex.
4) The first threads (I) enters WaitForMultipleObjects
and finds out that the signal object is in a
signalled state and exits the wait.
5) Thread (I) grabs the mutex and checks result status.
The number of waiters is decreased and becomes equal
to 0. The event returned was a signal event so the
broadcast gate isn't opened. The mutex is released.
6) Thread (II) issues a new broadcast. The mutex is
acquired but the number of waiters are 0 hence
the broadcast gate remains closed.
7) Thread (I) enters the wait again but is blocked by
the broadcast gate.
This fix resolves the above issue by always resetting
broadcast gate when there are no more waiters in th queue.
Backport from 6.0 to 5.1.
Only those sync points are included, which are used in debug_sync.test.
The Debug Sync Facility allows to place synchronization points
in the code:
open_tables(...)
DEBUG_SYNC(thd, "after_open_tables");
lock_tables(...)
When activated, a sync point can
- Send a signal and/or
- Wait for a signal
Nomenclature:
- signal: A value of a global variable that persists
until overwritten by a new signal. The global
variable can also be seen as a "signal post"
or "flag mast". Then the signal is what is
attached to the "signal post" or "flag mast".
- send a signal: Assign the value (the signal) to the global
variable ("set a flag") and broadcast a
global condition to wake those waiting for
a signal.
- wait for a signal: Loop over waiting for the global condition until
the global value matches the wait-for signal.
Please find more information in the top comment in debug_sync.cc
or in the worklog entry.
- Create the "dummy" thread joinable and wait for it to
exit before continuing in 'my_thread_global_init'
- This way we know that the pthread library is initialized
by one thread only
Option "--without-server" still not working in 5.1
The general approach is to make sure that source files
which require thread support are only compiled if the build
really needs thread support,
which means when the server is built or a thread-safe client
library.
This required several changes:
- Make sure the subdirectories "storage/" and "plugin/" are
only processed if the server is built, not ifclient-only.
- Make the compilation of some modules which inherently
require threading depend on thread supportin the build.
- Separate the handling of threading in "configure.in" from
that of server issues, threading is also needed in a
non-server build of a thread-safe client library.
Also, "libdbug" must get built even in a client-only build,
so "dbug/" must be in the list of client directories.
In addition, calls to thread functions in source files which
can be built without thread support must use the wrapper
functions which handle the non-threaded build.
So the modules "client/mysqlimport.c" and "client/mysqlslap.c"
must call "my_thread_end()" only via "mysql_thread_end()".
can crash under load
Merge from 5.0, after backport from 5.1/5.4 to 5.0.
This makes the fixes for
Bug 44068 (RESTORE can disable the MyISAM Key Cache)
Bug 40944 (Backup: crash after myisampack)
available to 5.1.
can crash under load
Backport from 5.1.
Does also include key cache fixes from:
Bug 44068 (RESTORE can disable the MyISAM Key Cache)
Bug 40944 (Backup: crash after myisampack)
CREATE TABLE...LIKE...
The mysql server option 'sync_frm' is ignored when table is created with
syntax CREATE TABLE .. LIKE..
Fixed by adding the MY_SYNC flag and calling my_sync() from my_copy() when
the flag is set.
In mysql_create_table(), when the 'sync_frm' is set, MY_SYNC flag is passed
to my_copy().
Note: TestCase is not attached and can be tested manually using debugger.
