… is MySQL Hints, such as SQL_BIG_RESULT, STRAIGHT_JOIN, FORCE INDEX etc. You place these directly into the query to change how query… know query is going to require large sort you can do SET sort_buffer_size=50000000 before executing query and SET sort_buffer_size=DEFAULT after executing the…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…in the presentation to convert sort to the union for…insert buffer will not be able to be …to differ only by first column. Regarding changing primary key to…how MySQL will execute the join. If it will fist lookup Table2 using some other index and when go to Table1 to… of total size or less to almost 100…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…to 2010′; mysql> use ontime1; Database changed mysql…to show (click show/hide to change the columns) That the “public dns” field is selected SSH to…buffer-size=512K read-rnd-buffer-size=1M skip-host-cache skip-name-resolve sort-buffer-size…
Post: MySQL: what read_buffer_size value is optimal ?
September 17, 2007 By 25 Comments
… surprising results with sort performance and today I’ve discovered even read_buffer_size selection may be … to some high value. Sample my.cnf values on large memory sizes recommend 1M settings and MySQL … In this case I’m really curious how much values change on different platforms (OS and Hardware) …
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…buffer_size, while MariaDB introduces a different variable to control the MRR buffer size mrr_buffer_size. Both buffer sizes default to 256K in MySQL…sorting overhead which means that the queries are just a bit slower as compared to MySQL 5.5 MRR clearly changes the access pattern to…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
… key on col1 would be sorted by col1 i.e. in…_buffer_size=6M read_rnd_buffer_size=6M Also note that the following changes were… workload Now let’s see how effective are the join optimizations…to MySQL 5.5 While with join_buffer_size set to 6M and read_rnd_buffer_size set to 6M, the query time for MySQL…
Comment: MySQL Server Memory Usage
September 1, 2006 By 21 Comments
…buffer_size=32M # Only for MyISAM which isnt used. sort_buffer_size=2M query_cache_size=10M # Might be increased thread_cache_size…buffer_size=8M # Lowered from 32M according to MySQL innodb_additional_mem_pool_size=20M innodb_file_io_threads=4 innodb_lock_wait_timeout=15 # CHANGED…
Post: MySQL Users Conference - Innodb
May 9, 2007 By 6 Comments
… average size pages were compressed to for data and for various indexes. How … to be available. Building index by sort allows to build them physically sorted…change to watch out for. So these are all possibilities but are we expected to…than buffer-pool which had it locking relaxed in latest MySQL 5…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…to change. We also want to know the operating mode you expect us to work in. Maybe you want us to…how to read these, there’s a full explanation in our book, High Performance MySQL…to read. If the InnoDB buffer pool is set to 22GB, it’s much easier to…
Comment: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
…_changes_in_mysql , in documentation now at http://dev.mysql.com/doc/refman/5.6/en/server-default-changes…. costly queries and/or low query rates. sort_buffer_size is much improved over the past 2M …QA) use, accompanied by more tips about how and when to change the values. This will eventually end …
