…mention this contest Tweet “My favorite #MySQL conference session” with a link to your… it. It is OK to enter multiple times — each time you enter increases…’ll select the lucky winners at random from all of the entries combined,… blog entry here to announce the results. Make sure we (or our sponsor)…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… this could mean a lot of random lookups in case the dataset does…you could be reading the same page multiple times into the buffer pool. So …to see the difference in numbers. Benchmark results For the purpose of this benchmark,…status counters. Counter Name MySQL 5.5 MySQL 5.6 MySQL 5.6 w/ join_buffer…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… from the system. What I usually look for MySQL is performance in random reads and random writes. Sequential reads and writes are rarely… does not initialize random generator. If you’re doing multiple runs make sure to add –init-rng=1 option otherwise results can be… we use one thread or multiple threads. As you also can see BBU is helpful even for random writes if they are…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
…seeking all over for random I/O, then other I/O (including non-random I/O) is likely… are many subtleties including the possibility of having multiple key caches. But I’ll give the simple…second intervals and compare the results to your IO system’s capabilities. MySQL doesn’t have good instrumentation…
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
… is IO bound or CPU bound, while to understand if MySQL goes through more rows than it needs to requires look… point of the article. In original article I mentioned having multiple hard drives does not help if you have single query… and so can result in multiple outstanding requests to the disk. Though this does not help dramatically for many “random” update queries. After…
Post: Multiple column index vs multiple indexes
August 22, 2008 By 13 Comments
…CHARSET=latin1 I have populated this table with random data for i and j having both …I ran them multiple times and measured time appropriately. To remove the overhead of starting MySQL etc …;i /dev/null In the result table I compute per query results and present results in milliseconds. Query 1000 …
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
…be completely random. We’ll need to perform 30 millions of random row reads…MySQL single query runs as single thread (with exeption of MySQL Cluster) and MySQL …several, run in parallel and aggregate result sets. So if you’re …problems solved just doing so. Use multiple servers to host portions of data…
Post: Missing Data - rows used to generate result set
July 20, 2008 By 15 Comments
…scan row accesses may be much faster than random index lookups row accesses in the same table…multiple tables or if you have GROUP BY query the number of rows which need to be utilized to create the result…) is the number of rows which MySQL used to generate result set. Comparing this number with …
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
… how many systems they have” on MySQL UC2008 Scalability Panel ? Indeed disks MAY… fetch few rows to show search results which does not require too much … So your hard drive can do 200 random reads per second and your SSD … you need enough concurrency to utilize multiple hard drives and with 50 drives …
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
…of Innodb scalability with multiple threads and multiple concurrent transactions ? HT: The…decides to schedule sequential read-ahead, random read ahead ? HT: InnoDB …used for read ahead and results were significant. They however …innodb.cc in 5.1: static MYSQL_SYSVAR_ULONG(thread_concurrency, srv…
