…_event_wait_low,sync_array_wait_event,rw_lock_s_lock_spin,pfs_rw_lock_s_lock_fu nc,btr_search_build_page_hash_index…_event_wait_low,sync_array_wait_event,rw_lock_x_lock_func,pfs_rw_lock_x_lock_fu nc,btr_search_build_page_hash…_event_wait_low,sync_array_wait_event,rw_lock_s_lock_spin,pfs_rw_lock_s_lock_fu nc,btr_search_build_page_hash_index…
Post: The perils of InnoDB with Debian and startup scripts
January 28, 2009 By 13 Comments
… time read locked in file btr0sea.c line 746 Last time write locked in file btr0sea.c line 1624 Mutex spin waits 0, rounds 5023577, OS waits 24953 RW-shared spins 34364070, OS waits 33800501; RW-excl spins 5756394, OS waits 5297208 Everyone is waiting…
Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
…_array_reserve_cell (sync0arr.c:366) ==9090== by 0x6BC917F: rw_lock_s_lock_spin (sync0rw.c:415) ==9090== by 0x6B6905A: log_checkpoint (sync0rw…:4035) ==9090== by 0×561388: main (mysqld.cc:4504) The RW lock spin stats join the company of the buffer pool and I… kind of error: lock order violation, thus a potential deadlock. The locks in question are LOCK_global_system_variables and LOCK_system_variables_hash…
Comment: Understand InnoDB spin waits, win a Percona Live ticket
October 24, 2012 By 2 Comments
… the number of times it wasn’t free even after spinning a little while” = Round According to this second definition of… of wait loops done and Spin Wait the times the mutex was checked and it was locked? Moreover, every how many Loops… numbers: In 19812448 Loops , 5870888 times the mutex was found locked. So the mutex was checked at least every 3 rounds…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…_row_lock_current_waitsblogpercona.commanual Innodb_row_lock_timeblogpercona.commanual Innodb_row_lock_time_avgblogpercona.commanual Innodb_row_lock_time_maxblogpercona.commanual Innodb_row_lock_waitsblogpercona.commanual Innodb_rows_deletedblogpercona.commanual Innodb_rows_insertedblogpercona.commanual Innodb_rows_readblogpercona.commanual Innodb_rows_updatedblogpercona.commanual innodb_spin…
Comment: kernel_mutex problem. Or double throughput with single variable
December 4, 2011 By 17 Comments
… the limiting mutex for your workload the different amount of spinning might make sense. Better solution would be to have this… makes sense to wait. For example if we run long spin and can discover we either get the mutex after 10us… 1000us we can decide to spin up to 20us or so which will deal with short locks of given mutex and switch…
Comment: MySQL on Amazon RDS part 2: Determining Peak Throughput
March 28, 2011 By 4 Comments
…_mem_pool_size 2097152 innodb_autoextend_increment 8 innodb_autoinc_lock_mode 1 innodb_buffer_pool_size 55050240000 innodb_change_buffering…_force_recovery 0 innodb_io_capacity 200 innodb_lock_wait_timeout 50 innodb_locks_unsafe_for_binlog OFF innodb_log_buffer_size…_mode OFF innodb_support_xa ON innodb_sync_spin_loops 30 innodb_table_locks ON innodb_thread_concurrency 0 innodb_thread_sleep…
Comment: Returning to InnoDB scalability
September 13, 2006 By 42 Comments
… 5160) +——————————–+————-+————–+————+————-+———-+———–+—————+ | Mutex | Module | Count | Spin_waits | Spin_rounds | OS_waits…0 | 0 | 0 | 0 | 0 | | rw_lock_mutexes | | 110855726270 | 1283069365 | 1479866288 | 1218471 | 206895 |…
Comment: kernel_mutex problem. Or double throughput with single variable
December 2, 2011 By 17 Comments
Davi, If I following: pthread_mutex_lock(&cond_mutex); pthread_cond_wait(&cond, &cond_mutex); printf(“T … thread wakes it comes back to SPIN LOOP Simplifying, InnoDB mutex looks like: mutex_enter(): { spin_loop: from i:=1 to innodb…_time); if mutex is not granted: pthread_cond_wait() goto: spin_loop; } mutex_exit: { pthread_cond_broadcast() } That is all threads…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… AMI images You can easily test Shard-Query for yourself. Spin up the desired number of EC2 instances using on of the the AMI images. You should spin a number of instances that evenly divides into 20 for…=0 innodb-stats-sample-pages=256 innodb-stats-update-need-lock=0 innodb-status-file innodb-strict-mode innodb-thread-concurrency…
