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| author | Satya B <satya.bn@sun.com> | 2009-12-17 16:55:50 +0530 |
|---|---|---|
| committer | Satya B <satya.bn@sun.com> | 2009-12-17 16:55:50 +0530 |
| commit | 801deedcf265bd3fe90e45c93b37133b68a19ba9 (patch) | |
| tree | 87609fa5cc213739e3ae187b8aab891ce002534d /mysys | |
| parent | 092f25caeb80f7473d2e76afd996bea38e7700fd (diff) | |
| download | mariadb-git-801deedcf265bd3fe90e45c93b37133b68a19ba9.tar.gz | |
Fix for Bug#37408 - Compressed MyISAM files should not require/use mmap()
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.
Diffstat (limited to 'mysys')
| -rw-r--r-- | mysys/my_thr_init.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/mysys/my_thr_init.c b/mysys/my_thr_init.c index 64fc99952e9..8dcffaebbbb 100644 --- a/mysys/my_thr_init.c +++ b/mysys/my_thr_init.c @@ -30,7 +30,9 @@ pthread_key(struct st_my_thread_var, THR_KEY_mysys); #endif /* USE_TLS */ pthread_mutex_t THR_LOCK_malloc,THR_LOCK_open, THR_LOCK_lock,THR_LOCK_isam,THR_LOCK_myisam,THR_LOCK_heap, - THR_LOCK_net, THR_LOCK_charset, THR_LOCK_threads; + THR_LOCK_net, THR_LOCK_charset, THR_LOCK_threads, + THR_LOCK_myisam_mmap; + pthread_cond_t THR_COND_threads; uint THR_thread_count= 0; uint my_thread_end_wait_time= 5; @@ -143,6 +145,7 @@ my_bool my_thread_global_init(void) pthread_mutex_init(&THR_LOCK_lock,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_isam,MY_MUTEX_INIT_SLOW); pthread_mutex_init(&THR_LOCK_myisam,MY_MUTEX_INIT_SLOW); + pthread_mutex_init(&THR_LOCK_myisam_mmap,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_heap,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_net,MY_MUTEX_INIT_FAST); pthread_mutex_init(&THR_LOCK_charset,MY_MUTEX_INIT_FAST); @@ -208,6 +211,7 @@ void my_thread_global_end(void) pthread_mutex_destroy(&THR_LOCK_lock); pthread_mutex_destroy(&THR_LOCK_isam); pthread_mutex_destroy(&THR_LOCK_myisam); + pthread_mutex_destroy(&THR_LOCK_myisam_mmap); pthread_mutex_destroy(&THR_LOCK_heap); pthread_mutex_destroy(&THR_LOCK_net); pthread_mutex_destroy(&THR_LOCK_charset); |