June 19, 2013

Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

March 21, 2012 By 10 Comments

….5. This blog post is aimed at the optimizer enhancement Multi Range Read (MRR). Its available in both MySQL 5.6 and… what this optimization actually is and what benefits it brings. Multi Range Read With traditional secondary index lookups, if the columns that… 5.6 and MariaDB 5.5. Handler_mrr_rowid_refills counts how many times the buffer used by MRR had to…

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: , , , , , , , , , , , , , ,

Post: Sphinx search performance optimization: multi-threaded search

January 16, 2013 By 10 Comments

… some CPU-intensive operations such as ranking, ordering or even COUNT with GROUP BY and if data nodes return large amounts… way to split data, you may want these to be ranges by using a helper table in MySQL to define those ranges, mixing it with sql_query_range or something else, depending on how your…

Filed Under: MySQL Tagged With: , , ,

Post: Ultimate MySQL variable and status reference list

January 8, 2011 By 4 Comments

…_sizeblogpercona.commanual Questionsblogpercona.commanual rand_seed1blogpercona.commanual rand_seed2blogpercona.commanual range_alloc_block_sizeblogpercona.commanual read_buffer_sizeblogpercona.commanual read_onlyblogpercona….commanual Select_full_joinblogpercona.commanual Select_full_range_joinblogpercona.commanual Select_rangeblogpercona.commanual Select_range_checkblogpercona.commanual Select_scanblogpercona.commanual server_idblogpercona…

Filed Under: Insight for DBAs, MySQL

Post: Why MySQL could be slow with large tables ?

June 9, 2006 By 141 Comments

… (ie old and rarely accessed data stored in different servers), multi-server partitioning to use combined memory and a lot of… times for full table scan vs range scan by index: mysql> select count(pad) from large; +————+ | count(pad) | +————+ | 31457280 | +————+ 1 row in set…

Filed Under: Insight for DBAs Tagged With: ,

Post: InnoDB vs MyISAM vs Falcon benchmarks - part 1

January 8, 2007 By 117 Comments

… in Part 2). There MyISAM shows bad scalability with increasing count of thread. I think the reason is pread system call… fixed, as this is specific Falcon’s way to handle multi-versioning. I think this is a big weakness of Falcon… Falcon by 1.64 – 3.85 times. READ_PK_RANGE_INDEX Query: SELECT count(id) FROM $tableName WHERE id between %d and…

Filed Under: Benchmarks Tagged With: ,

Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact

March 12, 2012 By 12 Comments

…-Tree index lookups have some limitations in cases such as range scans, where index parts after the part on which range condition is applied cannot be used for filtering records. For …

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: , , , , , , ,

Post: InnoDB benchmarks

January 3, 2007 By 15 Comments

…. Problems in InnoDB that were fixed: Thread trashing issues with count of theads 100+. In this case performance of InnoDB degraded… for our needs I developed benchmark suite which support wide range of tables and queries. The schema and used queries is… table scan. Range queries is especially interesting for bug 15815 as the same such queries were affected on multi-CPU systems. Used…

Filed Under: Benchmarks Tagged With: ,

Comment: Analyzing air traffic performance with InfoBright and MonetDB

November 28, 2009 By 50 Comments

…Infobright Enterprise Edition (3.2.2) which has a multi-threaded loader. I loaded different years and my …) or around 2,560 seconds. The total record count was 70,097,260 records. Another way of … used by multiple … — field for analysis across a range of years. AirlineID SMALLINT NOT NULL, — 8 An …

Filed Under: Benchmarks, MySQL Tagged With: , , ,

Post: MySQL Users Conference - Innodb

May 9, 2007 By 6 Comments

… faster for IO Bound Index scans and large range scans. We surely should benchmark this aspect separately…. lock for full statement duration. The problem with multi value inserts however is the following – even if… sure if Heikki will find a way to count exact number of auto increment values needed or…

Filed Under: Events and Announcements Tagged With: