…MySQL 5.1 get MySQL slow query log logged in mysql.slow_log table instead of the file as you had in… finding how many queries were accumulated in the logs or finding 10 last queries is not fast. The good…, neither you can delete rows from it (or do any write queries) only read access is possible, with…
Post: XtraDB: The Top 10 enhancements
August 13, 2009 By 5 Comments
…Last week I talked about why you don’t want to shard. This week I’m following up with the top 10 enhancements that XtraDB has over the built-in InnoDB included in MySQL…read_threads, innodb_write_threads (see docs). Better Diagnostics – The SHOW ENGINE INNODB STATUS command in…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… things. In MySQL 5 number of Innodb performance counters were exported and now available in SHOW…2: len 7; hex 00000040150110; asc @ ;; 3: len 10; hex 61202020202020202020; asc a ;; *** (2) TRANSACTION: …0.00 reads/s Finally last section – row operations which shows activity on the row basics and …
Post: Enum Fields VS Varchar VS Int + Joined table: What is Faster?
January 24, 2008 By 30 Comments
…means to retrieve each row MySQL will have to perform OS system call to read the row, at this …rows: 225690 Extra: 2 rows in set (0.10 sec) Because we refer state by name, which is unique,it is pre-read…. And the last test – selecting city and name in arbitrary order, skipping first 10000 rows to make…
Post: Estimating Replication Capacity
July 20, 2010 By 4 Comments
…mysql> select * from information_schema.user_statistics where user=”#mysql_system#” \G *************************** 1. row *************************** USER: #mysql…: 0 ROWS_FETCHED: 0 ROWS_UPDATED: 127576 TABLE_ROWS_READ:…0 1 row in set (0.00 sec) In … 0 0 0 # Last errn 34…logs applies for 10 minutes we …
Post: EXPLAIN EXTENDED can tell you all kinds of interesting things
June 15, 2010 By 7 Comments
…reading const tables | +—-+————-+——-+——+—————+——+———+——+——+—————————————————–+ 1 row in set, 1 warning (0.04 sec) mysql…Last, EXPLAIN EXTENDED can show you information about the query rewrites that MySQL…
Post: Find where your data is replicated, win a Percona Live ticket
October 21, 2011 By Leave a Comment
… Monday, so this is the last in the series of free-Percona-Live… have you ever wondered what servers are in your MySQL replication hierarchy? We have, too. … not read_only Filters replicate_wild_ignore_table=foo%.mount% Binary logging ROW Slave… InnoDB version 1.0.6-unknown +- 10.153.116.5 Version 5.1…
Post: Do you always need index on WHERE column ?
August 28, 2007 By 17 Comments
…, but this topic popups again and again. Today I’ve read opinion that if we have clause WHERE has_something=1… row in set (20.27 sec) mysql> select count(name) from testr ignore key (has_something) where has_something=0; 1 row in set (10.62…) mysql> select count(name) from testr ignore key (has_something) where has_something=0; 1 row in set (10.43 sec) So only in the last…
Post: Analyzing air traffic performance with InfoBright and MonetDB
October 2, 2009 By 50 Comments
…In total raw data is about 55GB. Average amount of rows in…10) DEFAULT NULL, `Div5LongestGTime` varchar(10) DEFAULT NULL, `Div5WheelsOff` varchar(10) DEFAULT NULL, `Div5TailNum` varchar(10) DEFAULT NULL ) ENGINE=BRIGHTHOUSE DEFAULT CHARSET=latin1; Last…in InfoBright. MySQL…
Post: Logging Foreign Key errors
September 27, 2012 By Leave a Comment
…seconds and will check the last error every 10 seconds. 3- Cause an error…mysql> select * from test.foreign_key_errors\G *************************** 1. row *************************** ts: 2012-09-26 14:28:31 error: Error in… key errors log them. Just reading the last error happened on the databases is…
