…NOT NULL, k INTEGER UNSIGNED DEFAULT ’0′ NOT NULL, c CHAR(120) DEFAULT ” NOT NULL, pad CHAR(60) DEFAULT ” NOT NULL…sbtest$I_r1000, with roll-up sum for 10, 100, 1000 records… both InnoDB and TokuDB performs if PK is (`id`,`hid`,`mid…= 1 myisam_recover socket=/var/lib/mysql/mysql.sock user=root skip-…
Post: How to convert MySQL's SHOW PROFILES into a real profile
February 20, 2012 By 12 Comments
…Sakila sample database to demonstrate: mysql> SET profiling=1; mysql> pager cat > /dev/null mysql> SELECT * FROM nicer_but_…time (the amount of time not accounted by the profiling). That is, the SUM(DURATION) isn’t … to subtract the SUM(DURATION) from the query’s real response time. If there were, I …
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…IF NOT EXISTS lineorder ( LO_OrderKey bigint not null, LO_LineNumber tinyint not null, LO_CustKey int not null, LO_PartKey int not null, LO_SuppKey int not null, LO_OrderDateKey int not null…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
…if you close connection. In Percona Server you can do better as you can query temporary tables too: mysql> select sum…both in memory and not): mysql> select * from information_schema.global…: 0 CREATE_TIME: NULL UPDATE_TIME: NULL *************************** 2. row *************************** SESSION_…
Post: The case for getting rid of duplicate “sets”
May 17, 2011 By 2 Comments
…NOT NULL DEFAULT ’0′ ) ENGINE=MyISAM DEFAULT CHARSET=latin1 | +——-+—————————————————————————————————–+ 1 row in set (0.00 sec) mysql…
Post: How fast can MySQL Process Data
April 9, 2008 By 3 Comments
…NOT NULL ) ENGINE=MEMORY DEFAULT CHARSET=latin1 mysql> select count(*) from m; +———-+ | count(*) | +———-+ | 1047684 | +———-+ 1 row in set (0.00 sec) mysql…enough if …mysql> select sum(i) from m3; +———+ | sum(i) | +———+ | 3492290 | +———+ 1 row in set (1.86 sec) mysql…
Post: Optimizing repeated subexpressions in MySQL
January 23, 2009 By 11 Comments
…MySQL optimizer? If it sees an expression repeated many times, does it realize they’re all the same and not… results to /dev/null. Results: 31s wall-…sum, 7), pow(@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…
Post: MySQL 6.0 vs 5.1 in TPC-H queries
March 25, 2008 By 17 Comments
…new MySQL 6.0 version. Query is pretty simple SELECT sum(l_extendedprice …NOT NULL, `l_commitdate` date NOT NULL, `l_receiptdate` date NOT NULL, `l_shipinstruct` char(25) NOT NULL, `l_comment` varchar(44) NOT NULL, `l_shipmode` char(10) NOT NULL…is that MySQL is wrong choosing index scan here. If we …
Post: Hidden columns of query_review_history table
August 28, 2012 By Leave a Comment
… pt-query-digest to process a MySQL slow query log and store historical values for …values: pct|avt|cnt|sum|min|max|pct_95|stddev|median|rank If the column ends with one…(64) DEFAULT NULL – Current database that comes from USE database statements. * `hostname_max` varchar(64) NOT NULL – Hostname of…
Post: Side load may massively impact your MySQL Performance
November 13, 2011 By 7 Comments
…sandbox.cnf test md_cache_test_big > /dev/null Baseline Run: When we run the tests …mysql [localhost] {msandbox} (information_schema) > select concat_ws(‘.’, t.schema, t.name, i.name) as index_name, sum…non zero value, if not I would strongly suggest changing default from zero in MySQL 5.6 as it…
