… disabled during these benchmark runs and that the disks are 4 5.4K disks in Software RAID5. Also note that the following… 1152 23231 130919 23228 130731 131497 Innodb_buffer_pool_read_requests 12947073 10228611 7816154 10251697 9319281 9393396 Innodb_buffer_pool_reads… are done, and less amount of data is read from disk, in fact half the amount of data is read from…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… disabled during these benchmark runs and that the disks are 4 5.4K disks in Software RAID5. Also note that the following… MariaDB 5.5 w/ mrr_buffer_size=4M Created_tmp_disk_tables 1 1 1 1 1 Created_tmp_tables 1…_ahead 0 20920 23669 20920 23734 Innodb_buffer_pool_read_requests 1361851 1264739 1235472 1263290 1235781 Innodb_buffer_pool_reads 120548…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in the same way this blog post is aimed at a new optimizer enhancement Index Condition …
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
… 2 disks to deal with. There is the serious difference however – if you have RAID1 for ANY request you can use any disk to perform the read request while with RAID0 it is only the disk which has the data (even keeping aside partial “border” IO request which…
Post: How much overhead is caused by on disk temporary tables
August 16, 2007 By 26 Comments
…0 | | Key_blocks_used | 7248 | | Key_read_requests | 2051451 | | Key_reads | 198208 | | Key_write_requests | 469220 | | Key_writes | 185808 | +————————+———+ 7 rows…temporary tables can be 10-100 times faster than disk based MyISAM tables Hopefully MySQL will implement support of…
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 15 Comments
… disks instead of just doing one IO to each of the disks. In this case even if this is the single IO request… doing the right thing. Say we have 6-disk RAID5 (so 5 bearing disks) with 64k stripe unit size and 4k file…’s no striping, with RAID0 number of bearing disks is actual number of disks (N), with RAID1+0 (RAID10) it’s N…
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
… many systems they have” on MySQL UC2008 Scalability Panel ? Indeed disks MAY be the most important part in your system performance… always the case. There are whole classes of systems where Disk performance is not that important – consider for example systems where… with 50 drives you would need at least 50 outstanding requests all the time to fully utilize them. So for example…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
… of requests to read a key block from the cache. Key_readsThe number of physical reads of a key block from disk…, because Key_reads actually aren’t physical disk reads at all. If the requested block of data isn’t in the operating system’s cache, then a Key_read is a disk read…
Post: Using LoadAvg for Performance Optimization
December 4, 2006 By 4 Comments
… is tricky question. Both for CPUs and for Disk there are two stages request can be. It can be ether currently executing… loaded response time starts to increase mainly because of time requests spend waiting in various queues and waiting on locks, the… another drive instead), and the fact disks can optimize multiple outstanding requests a bit better compared to requests coming one after another. For…
Post: Performance impact of complex queries
January 17, 2007 By 11 Comments
… truth is it still happens. Disk Starvation As Cache efficiency drops more requests have to hit the disk, which may be 100% busy… (sequential reads) its requests will be prioritized as they do not require disk head movement, compared to IO requests in random locations other threads are willing to take. Especially some older disk schedulers…
