…: ———- SEMAPHORES ———- OS WAIT ARRAY INFO: reservation count 50573942, signal count 48103669 Mutex spin waits 0, rounds 1286836814, OS waits 29544296 RW-shared spins 17771305, OS waits 8349871; RW-excl spins 10508828, OS waits 5276204 Currently I have innodb_sync…
Comment: kernel_mutex problem. Or double throughput with single variable
December 4, 2011 By 17 Comments
… innodb_sync_spin_loops is very interesting discussion because there is really no “right” answer – depending on what is the limiting mutex… makes sense to wait. For example if we run long spin and can discover we either get the mutex after 10us of… or so which will deal with short locks of given mutex and switch to OS wait and stop wasting CPU if not.
Comment: xtrabackup-1.2
May 10, 2010 By 2 Comments
…? OS: centos ,…InnoDB: The InnoDB memory heap is disabled InnoDB: Mutexes and rw_locks use InnoDB‘s own implementation InnoDB: Warning: innodb_file_io_threads is deprecated. Please use innodb…InnoDB: Setting file ./ibdata1 size to 10 MB InnoDB: Database physically writes the file full: wait… InnoDB…
Post: DROP TABLE and stalls: Lazy Drop Table in Percona Server and the new fixes in MySQL
June 22, 2012 By 33 Comments
…mutex for some time Exit the flush list mutex Exit the buffer pool mutex Try to force a context switch by advising the os…still access AHI, write queries would have to wait till the latch is unlocked. Now about the… The value of innodb_max_dirty_pages_pct was set at 90, while the InnoDB log files were…
Post: The performance effects of new patches
September 9, 2008 By 14 Comments
… storage. main common settings innodb_buffer_pool_size = 2048M innodb_thread_concurrency = 0 innodb_max_dirty_pages_pct = 70 innodb_flush_method = O_DIRECT…_pool_mutex_fixed_optimistic_safe.patch The patch splits global InnoDB buffer_pool mutex into several and eliminates waitings on flush IO and mutex when… seconds, and innodb_ibuf_contract_burst is used – comment from InnoDB code /* If there were less than 5 i/os during the one…
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
…_SCHEMA_MAX_MUTEX_INSTANCES | 1000000 | 3282 | | OLD_PASSWORDS | OFF | 0 | | INNODB_STATS_ON_METADATA | ON | OFF | | PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_SIZE | 10 | 5 | | PERFORMANCE_SCHEMA_EVENTS_WAITS_HISTORY_LONG_SIZE…/data/sandboxes/msb_5_6_10/data/msan | | VERSION_COMPILE_OS | linux2.6 | linux-glibc2.5 | | THREAD_CACHE_SIZE | 0 | 9…
Comment: Jeremy Cole on MySQL Replication
June 14, 2006 By 12 Comments
…mutex which makes it very expensive to do sync_binlog=1 unless you have battery backed up cache and if your OS…thread does but it can be significant. Innodb also has log mutex which protects log writes. In … meaning it can commit several transactions which are waiting to be commited at the same time …
Comment: Modeling InnoDB Scalability on Multi-Core Servers
January 27, 2011 By 11 Comments
… well. There are (or were) a couple of internal mutexes in the system around things like the key cache…cache and about 70G of free buffer space (for OS disk cache). The other 40G or so was app… little io wait). For our use cases, we got much better throughput on the big boxes with innodb, even for …
