… buffer pool we use following queries: select avg(id) from sbtest$i force key (primary) select count(*) from sbtest$i WHERE k… –mysql-socket=/tmp/mysql.sock –oltp-point-selects=1 –oltp-simple-ranges=0 –oltp-sum-ranges=0 –oltp-order-ranges=0 –oltp… –mysql-socket=/tmp/mysql.sock –oltp-point-selects=9 –oltp-simple-ranges=0 –oltp-sum-ranges=0 –oltp-order-ranges=0 –oltp…
Post: Benchmarking Percona Server TokuDB vs InnoDB
May 7, 2013 By 32 Comments
…_r10, sbtest$I_r100, sbtest$I_r1000, with roll-up sum for 10, 100, 1000 records in the main table. and… `hid`,`mid` is low selectivity is not good for fast inserts, but it is suitable for range selects by `id`. However it… if PK is (`id`,`hid`,`mid`). This also will affect select performance, so we will need to measure that also. And…
Post: Percona XtraDB Cluster 5.5.30-23.7.4 for MySQL now available
April 17, 2013 By 2 Comments
… the range [0, 255] (inclusive). Quorum is computed using weighted sum over group members. Percona XtraDB Cluster binary will now be… fixed #1158443 (Raghavendra D Prabhu). In case CREATE TABLE AS SELECT statement was running in parallel with the DDL statement on the selected table, in some cases first statement could be left hanging…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
… the queries (just to use ANSI JOIN syntax): — Q1.1 select sum(lo_extendedprice*lo_discount) as revenue from lineorder join dim… between 1 and 3 and lo_quantity < 25; -- Q1.2 select sum(lo_extendedprice*lo_discount) as revenue from lineorder join dim… 6 and lo_quantity between 26 and 35; — Q1.3 select sum(lo_extendedprice*lo_discount) as revenue from lineorder join dim…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
…: mysql> select sum(total_lines) from complete_example2; +——————+ | sum(total_lines) | +——————+ | 155187034 | <-- too high +------------------+ 1 row in set (0.68 sec) mysql> select sum(total… mysql> select sum(total_lines) from dashboard_customer_sales ; +——————+ | sum(total_lines) | +——————+ | 155186550 | +——————+ 1 row in set (0.64 sec) mysql> select sum(total_lines…
Post: A rule of thumb for choosing column order in indexes
June 5, 2009 By 15 Comments
… full table scan. EXPLAIN says there are no possible_keys. SELECT * FROM tbl WHERE status=’waiting’ AND source=’twitter’ AND no…
Post: How adding another table to JOIN can improve performance ?
August 1, 2008 By 12 Comments
…,70,80,90,100); +————-+ | sum(events) | +————-+ | 3289092 | +————-+ 1 row in set (1.04 sec) mysql> explain select sum(events) from info where d… block equality propagation by using some trivial function: mysql> explain select sum(events) from info,dl where myday between ’2007-01-01…
Post: Optimizing repeated subexpressions in MySQL
January 23, 2009 By 11 Comments
…: select sql_no_cache pow(@sum := (select sum(rental_id) from sakila.rental), 1), pow(@sum, 2), pow(@sum, 3), pow(@sum, 4), pow(@sum, 5), pow(@sum, 6), pow(@sum, 7), pow(@sum…
Comment: Optimizing repeated subexpressions in MySQL
January 25, 2009 By 11 Comments
…(sum, 8), pow(sum, 10), pow(sum, 11), pow(sum, 12), pow(sum, 13), pow(sum, 14), pow(sum, 15), pow(sum, 16), pow(sum, 17), pow(sum, 18) FROM (SELECT sum(rental_id) as sum FROM…
Comment: Optimizing repeated subexpressions in MySQL
January 24, 2009 By 11 Comments
…(@sum, 8), pow(@sum, 10), pow(@sum, 11), pow(@sum, 12), pow(@sum, 13), pow(@sum, 14), pow(@sum, 15), pow(@sum, 16), pow(@sum, 17), pow(@sum, 18) FROM (SELECT @sum := (SELECT sum(rental_id) FROM sakila.rental)) a In this query @sum is…
