…strace) are great tools for MySQL Performance analyses. Too many people end…. A while ago I measured over 10 times slow down over time as memory becomes fragmented …These already can be used for Innodb Buffer Pool and Key Buffer…for sake of speeding up the reads and more optimal resource allocation -…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
…performance. This especially apples to index lookus and joins which we cover later. As everything usually slows down…times difference. Here is little illustration I’ve created the table with over… also clustered keys in Innodb which combine index access…need to perform 30 millions of random row reads, …
Post: How innodb_open_files affects performance
November 18, 2009 By 4 Comments
…performance was about the same, taking 1sec (on the second time) . Whenever innodb…down normally! InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd files… InnoDB: Restoring possible half-written data pages from the doublewrite InnoDB: buffer… InnoDB…slow downs…
Post: Side load may massively impact your MySQL Performance
November 13, 2011 By 7 Comments
… –max-time=180 –oltp-read-only –mysql-host=localhost –mysql-table-engine=innodb –…Performance of sysbench OLTP on small table drops more than 150 times when heavy mysqldump is running concurrently. mysqldump itself also slows down…is a dramatic improvement of over 150x for sysbench and results…
Post: Reasons for run-away main Innodb Tablespace
June 10, 2010 By 2 Comments
…update or delete transactions which go over a lot of rows. In …Long Transactions the time is a bad measure. Having transaction in read only … for ibdata1 file). “Good” thing is performance typically starts to suffer terribly …can use innodb_max_purge_lag to make a threads doing modifications slow down …
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…current performance, future performance,…get down …time looking at this. For one thing, all the values are in big units, so it’s hard to read. If the InnoDB…slow /path/to/slow.log By default, this outputs the top 10 most expensive queries, in total execution time. By the way, the slow…example) read over…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…innodb%read%’; +—————————————+—————-+ | VARIABLE_NAME | VARIABLE_VALUE | +—————————————+—————-+ | INNODB_BUFFER_POOL_READ_AHEAD_RND | 0 | | INNODB_BUFFER_POOL_READ_AHEAD | 0 | | INNODB_BUFFER_POOL_READ…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…over…InnoDB DEFAULT CHARSET=latin1 Test Cases Now let’s see the test cases and then see how the joins perform…time taken to complete the above query: First thing to note is that I have scaled down the time…reading…
Post: Using CHAR keys for joins, how much is the overhead ?
June 18, 2007 By 18 Comments
… than integer based join for Innodb. Finally I decided to check if using longer strings slows down things significantly and so I replaced… performance dropped down to 6.1 seconds which makes it over 2 times slower compared to integer based join. So how do I read these… joins compared to integer keys Performance degradation can range from few percent to couple of times for Innodb tables MyISAM Tables may suffer…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…over decent period of time. In the very start of printout Innodb will print: ===================================== 060717 3:07:56 INNODB…read-ahead may be performed which can increase average read size significantly. So you can think about this value as read…down…
