… virtual machines tend to handle process scheduling and timing much differently than traditional hardware, and I’ve … replication, it looks like you’ll need to wait for the next release of MHA. Q: How …That said, there are plenty of other MySQL and OS-level status variables that you might want to …
Post: Understand InnoDB spin waits, win a Percona Live ticket
September 2, 2011 By 2 Comments
… it waited in a spin-wait. rounds 19812448 is the number of times threads looped in the spin-wait cycle, checking the mutex. OS waits 375285 is the number of times the thread gave up spin-waiting…
Comment: Returning to InnoDB scalability
September 13, 2006 By 42 Comments
… | Mutex | Module | Count | Spin_waits | Spin_rounds | OS_waits | OS_yields | OS_waits_time | +——————————–+————-+————–+————+————-+———-+———–+—————+ | &(trx->undo_mutex) | trx0trx…
Comment: Returning to InnoDB scalability
August 4, 2006 By 42 Comments
… | Mutex | Module | Count | Spin_waits | Spin_rounds | OS_waits | OS_yields | OS_waits_time | +—————————+————-+————–+————+————-+———-+———–+—————+ | &(trx->undo_mutex) | trx0trx…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… flag 0 wait is ending Mutex spin waits 5672442, rounds 3899888, OS waits 4719 RW-shared spins 5920, OS waits 2918; RW-excl spins 3463, OS waits 3163… wait using sync_array Innodb tries to “yield” to OS hoping when name thread is scheduled next time object will be free already. OS Waits are relatively slow, and if you get tens of thousands of OS waits per second…
Post: The perils of InnoDB with Debian and startup scripts
January 28, 2009 By 13 Comments
… 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 for mutexes…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…os_log_fsyncsblogpercona.commanual Innodb_os_log_pending_fsyncsblogpercona.commanual Innodb_os_log_pending_writesblogpercona.commanual Innodb_os…nowblogpercona.commanual system_time_zoneblogpercona.commanual table_definition_cacheblogpercona.commanual table_lock_wait_timeoutblogpercona.commanual …
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
… we can use Innodb_data_reads , Innodb_data_writes, Innodb_os_log_fsyncs for your disk IO estimation. When you can… TIME” here, subtracting CPU time from it we get “Wait Time” which is in this case 775-49=726 seconds or 4005us per select. Wait time… between Wait Time and CPU time is very helpful to see how “wait free your system is”. If it system is already have low wait…
Comment: How to Identify Bad Queries in MySQL
January 11, 2011 By 16 Comments
… stack of SQL statements, ok? So accesspaths etc. (3) The OS and Storage – In the old days we had local disks… system? How much was the waiting compared to the work? ( that well known curve or responsetime = servicetime + waiting time). Instrumentation of the RDBMS… be cut down further because it’s executed a zillion times. Of course, this is not a diagnostic tool but a…
Comment: kernel_mutex problem. Or double throughput with single variable
December 4, 2011 By 17 Comments
… distribution we can design how long it makes sense to wait. For example if we run long spin and can discover… mutex after 10us of we spin till the end of time of 1000us we can decide to spin up to 20us… deal with short locks of given mutex and switch to OS wait and stop wasting CPU if not.
