… second MySQL Consulting work or even more frequently. IO Bound workload is quite different from CPU bound one, which happens when your working set… CPU bound to IO bound hits the most is there a lot of rows are analyzed – count queries, group by, order by without indexes, search… CPU bound case – yes you will but it will happen with 100.000 messages not 100 messages as in IO bound case which is…
Post: MySQL 5.5.8 - in search of stability
January 3, 2011 By 11 Comments
…initial run. Later I will change them in searching for optimal values. innodb_file_per_table = …files_in_group = 2 innodb_read_io_threads = 16 innodb_write_io_threads = 16 innodb_purge_threads=…percentage is kept at the 60% level, and checkpoint age is at the 2000MB level; that is, not bounded by…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… high values for any of these variables is indication of IO bound workload. Note however – IO requests submited by threads executing requests are not… while workload being IO bound still. Next, number of file IO operations is shown as well as computed averages. This is parameters which is great for… hash index is hash index Innodb builds for some pages to speed up row lookup replacing btree search with hash search. This section…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
… by one. So in the same way this blog post is aimed at a new optimizer enhancement Index Condition Pushdown (ICP… take a look briefly at what this enhancement actually is, and what is it aimed at. Index Condition Pushdown Traditional B-Tree…, where index parts after the part on which range condition is applied cannot be used for filtering records. For example, suppose…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
… even if 50% of rows are accessed, while for disk IO bound accessess we might be better of doing full table scan… for fully IO bound workload it will be able to provide just 100 row lookups by index pr second. The difference is 10… with queries examining only few rows it is less of the problem. Data retrieval, search, DSS, business intelligence applications which need to…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… where some prefix information is stored, and a search almost as efficient as a binary search can be performed….requests can be queued at once. Q13: Is there any IO concurrency control – how many random and …official InnoDB, though. PZ: If your load is CPU bound and you’re scaling out you can get…
Post: SystemTap - DTrace for Linux ?
September 14, 2009 By 17 Comments
…/08/oprofile-for-io-bound-apps.html). I.e. for IO-bound or for mutex contention problems OProfile is not that useful. SystemTap is included in…_isolation_level(iso=? ) innobase_release_stat_resources(trx=0x2aaaaaddb8b8 ) convert_search_mode_to_innobase(find_flag=? ) innodb_srv_conc_enter_innodb…
Post: Scaling: Consider both Size and Load
July 13, 2010 By 5 Comments
… 100.000 user accounts. You can see the CPU,IO and Network usage is below 10% of capacity – does it mean you… size. You can think about Google search engine – the data size on which search operation is performed is constant, no matter if you’re… memory, hence having CPU bound workload. As your data growths you may frequently find load becoming IO bound and hence things becoming 10x…
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
…trouble with backups etc – because Sphinx is doing all search heavy lifting we only need to…is paramount but taking number from other application is one of the worst mistakes you can make. One application can become CPU bound…have BBU most likely data files is where all IO will go. If you dedicate …
Post: Using delayed JOIN to optimize count(*) and LIMIT queries
April 6, 2007 By 22 Comments
… applications you would see main (fact) table which contains search fields and dimension tables which contain more information about facts … the join even if you use LEFT JOIN so it is not needed which slows down things considerably. In similar way…
