… each of the schedulers, while name remains the same. This means unless you really know mapping between kernel versions and scheduler versions it… over years. Long time ago “AS” scheduler could be several times slower than deadline for MySQL workloads such as SysBench or DBT2… the docs it is mentioned it uses “per process” scheduling while MySQL is single process but single thread – does each thread gets…
Post: Operation Systems do not provide good IO interface for Database Servers
May 11, 2006 By 2 Comments
… time I checked there was IO scheduler with these functions in works for Linux Kernel but I have not seen anything production… to happen in background when there are enough resources. IO Scheduler should execute these only if there is bandwidth available so… at DIKU We tested some protototype patches for Linux kernel and MySQL but we did not get anything ready for production up…
Comment: How Percona diagnoses MySQL server stalls
March 9, 2011 By 6 Comments
… bug! All mysql processes stuck in ‘umtxn’ status. I did many tests enabling all different combinations of cores in the kernel, rebooting… to test its new scheduler, but actually did not help (minimal). I really believe the combination FreeBSD scheduler + MySQL mutexes + Multicores (+ crappy php…
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
… it better to disable them. The MySQL Settings are probably what is the most interesting: MySQL 5.0 Tuning in /etc/my… in this workload without restricting number of threads inside Innodb Kernel. Again this is rather workload specific. innodb_sync_spin_loops… noatime, nologging mysqld moved into the FX scheduling class via priocntl -s -c FX mysql-pid “nologging” looks a bit scary here…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 11 Comments
…Linux Release | Ubuntu 10.04.2 LTS (lucid) Kernel | 2.6.32-31-server Architecture | CPU…) DIMM {OUT OF SPEC} Other … # Disk Schedulers And Queue Size ############################# sda | [deadline] 128 # RAID …, not different MySQL configurations, I didn’t try out different MySQL versions or …
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…thread declared inside InnoDB 442 mysql tables in use 1, locked 0 MySQL thread id 8079, query …This may cause number of threads active inside kernel being less than number of threads allowed …, state of Innodb main thread which controls scheduling of number of system operations – flushing dirty pages,…
Post: Setting up XFS on Hardware RAID -- the simple edition
December 16, 2011 By 9 Comments
… point mysql‘s tmpdir elsewhere) Everything else for MySQL (/mnt/data or similar): (sym-link /var/lib/mysql into here when you setup mysql… use some simple ones: /var/lib/mysql xfs nobarrier,noatime,nodiratime Setting the IO scheduler This is a commonly missed step related… scheduler in realtime And to make it permanent, add ‘elevator=
Post: XtraDB benchmarks - 1.5X gain in IO-bound load
December 18, 2008 By 30 Comments
… MySQL 5.1.30 trees – MySQL 5.1.30 with standard InnoDB, MySQL 5.1.30 with InnoDB-plugin-1.0.2 and MySQL… remember as Linux kernels 2.6.18+ (which are used on CentOS / RedHat 5.2) are coming with CFQ scheduler as default…/sda/queue/scheduler should be one of first things to do on new server (sure you also need to change kernel startup…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
… wrong. Q10: When Innodb decides to schedule sequential read-ahead, random read ahead ? HT: InnoDB schedules a sequential read-ahead when it… in an ascending order of the file address, then InnoDB schedules the read of all the 64 pages of the extent… most of the system’s memory the kernel can decide (incorrectly) to swap out MySQL. There are two solutions here. Memlock and…
Post: Performance impact of complex queries
January 17, 2007 By 11 Comments
… your normal working set from OS cache. Operation Systems and MySQL Itself employs various strategies to attempt to minimize such effect… milliseconds you would expect disk IO to take. Scheduling Issues OS Disk IO schedules may also “help” in this case. Number of… directory with couple of files. In recent Linux Kernels deadline or cfq IO schedulers should be better with this. So what can…
