mariadb

Tree: 322dfc9d11

Author	SHA1	Message	Date
Vladislav Vaintroub	4aea170bc6	A follow-up to the patch for bug #56405 "Deadlock in the MDL deadlock detector". This patch addresses performance regression in OLTP_RO/MyISAM test on Windows introduced by the fix for bug #56405. Thus it makes original patch acceptable as a solution for bug #56585 "Slowdown of readonly sysbench benchmarks (e.g point_select) on Windows 5.5". With this patch, MySQL will use native Windows condition variables and reader-writer locks if they are supported by the OS. This speeds up MyISAM and the effect comes mostly from using native rwlocks. Native conditions improve scalability with higher number of concurrent users in other situations, e.g for prlocks. Benchmark numbers for this patch as measured on Win2008R2 quad core machine are attached to the bug report. ( direct link http://bugs.mysql.com/file.php?id=15883 ) Note that currently we require at least Windows7/WS2008R2 for reader-writer locks, even though native rwlock is available also on Vista. Reason is that "trylock" APIs are missing on Vista, and trylock is used in the server (in a single place in query cache). While this patch could have been written differently, to enable the native rwlock optimization also on Vista/WS2008 (e.g using native locks everywhere but portable implementation in query cache), this would come at the expense of the code clarity, as it would introduce a new "try-able" rwlock type, to handle Vista case. Another way to improve performance for the special case (OLTP_RO/MYISAM/Vista) would be to eliminate "trylock" usage from server, but this is outside of the scope here. Native conditions variables are used beginning with Vista though the effect of using condition variables alone is not measurable in this benchmark. But when used together with native rwlocks on Win7, native conditions improve performance in high-concurrency OLTP_RO/MyISAM (128 and more sysbench users).	15 years ago
Konstantin Osipov	26cd9abe4f	A follow up for the fix for Bug#35164 (remove priorities on Windows).	16 years ago
Kristofer Pettersson	dfed28e750	Bug#47768 pthread_cond_timedwait() is broken on windows 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.	16 years ago
Vladislav Vaintroub	9cf8d12c85	Backport of this changeset http://lists.mysql.com/commits/59686 Cleanup pthread_self(), pthread_create(), pthread_join() implementation on Windows. Prior implementation is was unnecessarily complicated and even differs in embedded and non-embedded case. Improvements in this patch: * pthread_t is now the unique thread ID, instead of HANDLE returned by beginthread This simplifies pthread_self() to be just straight GetCurrentThreadId(). prior it was much art involved in passing the beginthread() handle from the caller to the TLS structure in the child thread ( did not work for the main thread of course) * remove MySQL specific my_thread_init()/my_thread_end() from pthread_create. No automagic is done on Unix on pthread_create(). Having the same on Windows will improve portability and avoid extra #ifdef's * remove redefinition of getpid() - it was defined as GetCurrentThreadId()	16 years ago
monty@mysql.com/narttu.mysql.fi	088e2395f1	WL#3817: Simplify string / memory area types and make things more consistent (first part) The following type conversions was done: - Changed byte to uchar - Changed gptr to uchar* - Change my_string to char * - Change my_size_t to size_t - Change size_s to size_t Removed declaration of byte, gptr, my_string, my_size_t and size_s. Following function parameter changes was done: - All string functions in mysys/strings was changed to use size_t instead of uint for string lengths. - All read()/write() functions changed to use size_t (including vio). - All protocoll functions changed to use size_t instead of uint - Functions that used a pointer to a string length was changed to use size_t* - Changed malloc(), free() and related functions from using gptr to use void * as this requires fewer casts in the code and is more in line with how the standard functions work. - Added extra length argument to dirname_part() to return the length of the created string. - Changed (at least) following functions to take uchar* as argument: - db_dump() - my_net_write() - net_write_command() - net_store_data() - DBUG_DUMP() - decimal2bin() & bin2decimal() - Changed my_compress() and my_uncompress() to use size_t. Changed one argument to my_uncompress() from a pointer to a value as we only return one value (makes function easier to use). - Changed type of 'pack_data' argument to packfrm() to avoid casts. - Changed in readfrm() and writefrom(), ha_discover and handler::discover() the type for argument 'frmdata' to uchar** to avoid casts. - Changed most Field functions to use uchar* instead of char* (reduced a lot of casts). - Changed field->val_xxx(xxx, new_ptr) to take const pointers. Other changes: - Removed a lot of not needed casts - Added a few new cast required by other changes - Added some cast to my_multi_malloc() arguments for safety (as string lengths needs to be uint, not size_t). - Fixed all calls to hash-get-key functions to use size_t. (Needed to be done explicitely as this conflict was often hided by casting the function to hash_get_key). - Changed some buffers to memory regions to uchar to avoid casts. - Changed some string lengths from uint to size_t. - Changed field->ptr to be uchar* instead of char*. This allowed us to get rid of a lot of casts. - Some changes from true -> TRUE, false -> FALSE, unsigned char -> uchar - Include zlib.h in some files as we needed declaration of crc32() - Changed MY_FILE_ERROR to be (size_t) -1. - Changed many variables to hold the result of my_read() / my_write() to be size_t. This was needed to properly detect errors (which are returned as (size_t) -1). - Removed some very old VMS code - Changed packfrm()/unpackfrm() to not be depending on uint size (portability fix) - Removed windows specific code to restore cursor position as this causes slowdown on windows and we should not mix read() and pread() calls anyway as this is not thread safe. Updated function comment to reflect this. Changed function that depended on original behavior of my_pwrite() to itself restore the cursor position (one such case). - Added some missing checking of return value of malloc(). - Changed definition of MOD_PAD_CHAR_TO_FULL_LENGTH to avoid 'long' overflow. - Changed type of table_def::m_size from my_size_t to ulong to reflect that m_size is the number of elements in the array, not a string/memory length. - Moved THD::max_row_length() to table.cc (as it's not depending on THD). Inlined max_row_length_blob() into this function. - More function comments - Fixed some compiler warnings when compiled without partitions. - Removed setting of LEX_STRING() arguments in declaration (portability fix). - Some trivial indentation/variable name changes. - Some trivial code simplifications: - Replaced some calls to alloc_root + memcpy to use strmake_root()/strdup_root(). - Changed some calls from memdup() to strmake() (Safety fix) - Simpler loops in client-simple.c	19 years ago
Kristofer.Pettersson@naruto.	cd0a43f528	Bug#25042 OPTIMIZE TABLE cause race condition in IO CACHE SHARE - The condition variable implementation "lost" a signal to WaitOnSingleObject when a semaphore was released. - The signal could be consumed by a new call to pthread_cond_wait before all waiting threads had awoken. - The new implementation of pthread_cond_* uses events instead of semaphores. It also uses an extra lock to protect entry into new cond wait before the broadcast has finished.	19 years ago
kent@mysql.com/kent-amd64.(none)	226a5c833f	Many files: Changed header to GPL version 2 only	19 years ago
msvensson@shellback.	c3fb91b782	Change windows pthread_cond_timedwait to use an absolute time value	19 years ago
msvensson@shellback.	c41e307d85	BUG#24687 func_misc test fails on win64 - Use same precision (milliseconds) for all time functions used when calculating time for pthread_cond_timedwait - Use 'GetSystemTimeAsFileTime' for both start and curr time	19 years ago
monty@hundin.mysql.fi	b658662ae4	Update copyright Fixed memory leak on shutdown (Affects the embedded version & MyODBC)	24 years ago
monty@donna.mysql.com	dc4525636c	Small bug fixes + code for DELETE QUICK	26 years ago
bk@work.mysql.com	f4c589ff6c	Import changeset	26 years ago

14 Commits (322dfc9d118ee876dc2adc2e898f94568e40896b)