… of defaults changes in MySQL 5.6 compared to MySQL 5.5 In general there are …is probably well too small to be useful but leaves impression it does not need to be configured. sort_buffer_size… efficiently automatically. join_buffer_size = 256k The default is now double of what it was previously. …
Post: What to tune in MySQL Server after installation
September 29, 2006 By 118 Comments
… to work as MySQL DBAs or be involved with MySQL Performance in some way is to ask them what should be tuned in MySQL Server straight after…_buffer_pool_size This is very important variable to tune if you’re using Innodb tables. Innodb tables are much more sensitive to buffer size… workload specific. If you have simple queries there is no reason to increase sort_buffer_size even if you have 64GB of memory to…
Post: What's required to tune MySQL?
July 27, 2011 By 4 Comments
… to deliver huge wins. If MySQL is actually badly configured, you can hurt…MySQL installations don’t suffer from the variety and severity of problems we write about here. Examples include what…In addition to unlikely circumstances, I sometimes see unlikely settings, such as making the sort buffer size…
Post: MySQL Server Memory Usage
May 17, 2006 By 21 Comments
…the question how should they estimate memory consumption by MySQL Server in given configuration. What is the formula they could use. The reasons …measure what you get in practice and how memory consumption reacts to changing various variables. For example you may find out increasing sort_buffer_size…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 4 Comments
…is used in conjunction with BKA and that is MRR Key-ordered Scan. Let’s see what this optimization actually is…’ optimizer_switch=’mrr_sort_keys=on’ optimizer_…is not entirely visible in the manual either for MariaDB or MySQL, but you need to appropriately increase read_rnd_buffer_size/mrr_buffer_size…
Post: How much memory can MySQL use in the worst case?
February 12, 2009 By 17 Comments
…is the one in the error log after a crash: “It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size…size is just a handy way to avoid repeated malloc() calls by doing it all up front in one call. And what… on my laptop: mysql> set @a := repeat(‘a’, 1024 * …
Post: What exactly is read_rnd_buffer_size
July 24, 2007 By 4 Comments
… for read_rnd_buffer_size you would find descriptions such as “The read_rnd_buffer_size is used after a sort, when reading rows in sorted order. If… converted to fixed size (basically everything but BLOB/TEXT) MySQL can use read_rnd_buffer to optimize data retrieval – As data is sorted by the…
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
…to disable them. The MySQL Settings are probably what is the most interesting: MySQL 5.0 Tuning in /etc/my.cnf (included in FDA) [mysqld] sql… requirement consider using this. sort_buffer_size = 32k – It is interested how much this was really investigated. Indeed this is much smaller than default. If…
Post: ALTER TABLE: Creating Index by Sort and Buffer Pool Size
June 27, 2012 By 4 Comments
…in RAID10. I used 10mil row table which would look as following in terms of data and index size: mysql…is what file merge process uses. This is important illustration as in many cases when people see performance reduction with large buffer pool they forget what…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 13 Comments
…different MySQL configurations, I didn’t try out different MySQL…size = 64M thread_cache_size = 32 query_cache_size = 0 tmp_table_size = 64M key_buffer_size = 8M bulk_insert_buffer_size = 8M myisam_sort_buffer_size = 8M myisam_max_sort_file_size…alignment settings in the file system. This is what you …
