…query cache query_cache_size = 0 query_cache_type = 0 You can see that the buffer pool is sized…query cache on write heavy workload. OK, so that was all about the configuration of the EC2 instance and MySQL…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… is the combined size of the secondary key tuples fetched, and N is the buffer size. In MySQL 5.6 the buffer size used by MRR can be controlled by the variable read_rnd_buffer_size, while MariaDB… hours in case of MySQL 5.5 and ~5 hours in case of MySQL 5.6 and MariaDB 5.5. Note that query cache is disabled…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… available in both MySQL 5.6 and MariaDB 5.5. You can read more about BKA in MySQL 5.6 here and BKA in MariaDB… dataset size ~5G). Note that query cache is disabled during these benchmark runs and that the disks are 4 5.4K disks in Software… 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…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
…in most cases you do not know where exactly memory is allocated. This was not much of the problem in MySQL…query execution, which size can be controlled by tmp_table_size and which also only exist for duration of query…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in… new optimizer enhancement Index Condition Pushdown (ICP). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take…
Comment: Too many connections? No problem!
March 15, 2012 By 28 Comments
… my website develop in PHP with MYSQL, these are MYSQL values: datadir=/data/mysql socket=/data/mysql/mysql.sock max_…queries=/var/log/mysql-slow-queries.log long_query_time=15 log-queries-not-using-indexes query_cache_type=1 query_cache_size=32M thread_cache_size=30 table_cache=4096 join_buffer_size…
Post: Beware large Query_Cache sizes
March 23, 2007 By 3 Comments
…had number of consulting projects with MySQL Query Cache being source of serious problems. One would see queries both for MyISAM and Innodb tables…if your query cache size is in Gigabytes. At the same time check how many queries do you have in cache – Qcache_queries_in_cache – if it is in hundreds of…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL manual, …queries_in_cacheblogpercona.commanual Qcache_total_blocksblogpercona.commanual Queriesblogpercona.commanual query_alloc_block_sizeblogpercona.commanual query_cache_limitblogpercona.commanual query_cache_min_res_unitblogpercona.commanual query_cache_sizeblogpercona.commanual query_cache…
Post: What to tune in MySQL Server after installation
September 29, 2006 By 116 Comments
… 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… have threads created in normal operation. query_cache_size If your application is read intensive and you do not have application level caches this can…
Post: Impact of the sort buffer size in MySQL
October 25, 2010 By 8 Comments
… to perform 12 queries like ‘select * from sorttest order by data limit 78000,1′ with, of course, the query cache disabled. I also verified that during the whole process, the computer never swapped and I pre-warmed the file cache before…/bash for i in `seq 1 1000` do START=`date +%s.%N` OUT=`mysql -e “set session sort_buffer_size=32*1024*$i…
