…select count(*) from longf; +———-+ | count(*) | +———-+ | 5242880 | +———-+ And simple PHP script which retrieves all rows from the table: < ?php $link = mysql_…to MySQL, without fetching and buffering the result rows automatically, as mysql_query() does. So mysql_query buffers all…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just … newest Firefox toolbar bookmark: an option and variable reference for all three sites in one! abort_slave_event_countblogpercona.commanual Aborted…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
…MySQL account and they have been normally treated very quickly by MySQL. The moment you give someone access to MySQL Server, all MySQL…in many cases you can use result overload to make MySQL to consume so much … statements and keep max_prepared_stmt_count very low. Prepared Statements and Blob …
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
… found and returned up to the top level MySQL part for processing are counted the Rows_examined remains zero. It looks simple… because the access type to the tables is “const” MySQL does not count it as access to two tables. In case of… in a simple way because scanning all that rows are actually needed to produce group by results. What you can think about…
Post: Accessing Percona XtraDB Cluster nodes in parallel from PHP using MySQL asynchronous queries
March 6, 2013 By 2 Comments
…result->fetch_row(); # Handle returned result mysqli_free_result($result); } else die(sprintf(“MySQLi Error: %s”, mysqli_error($link))); $processed++; } } while ($processed < count($all_links)); As conclusion, we see that using PHP with MySQLnd drivers we can execute 5 MySQL…
Post: Wow. My 6 year old MySQL Bug is finally fixed in MySQL 5.6
August 30, 2012 By 2 Comments
… simply responding with empty set MySQL truncates the constant, performs the lookup and only when discards results: CREATE TABLE `trunc` ( `i` int(11) NOT NULL default ’0′, KEY `i` (`i`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 mysql> select i,count… most cases, yet MySQL continues to be very loose by default. Consider running with sql_mode=strict_all_tables which will report…
Post: Testing MySQL column stores
August 16, 2010 By 15 Comments
… and speed of loading Accuracy of results of queries over the large data set Speed of results of queries over the large… not run some of the queries. ICE supports almost all of the MySQL aggregation functions. Notably, GROUP_CONCAT is not supported, which… not able to get accurate results for all of the queries on InfiniDB. In particular the query “select count(*) from carsales.sales_fact…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…be evaluated as math expression and the result will be IN(-2) which is …I also would note there are some MySQL optimizer restrictions in how well it …? A: Typically you do not need all your indexes to be in memory… doing a SELECT competition_id, COUNT(user_id) AS user_count FROM user_competition_entry …
Post: Explaining Indexes with a Library Metaphor
August 30, 2011 By 1 Comment
… the index cards, look up section H, find Hartley and count all the index cards that have Hartley, J.R in the… J.R. Hartley has written 4 books. You have your result and you have saved yourself from walking over to the… of the book is written on them. You get your result and saved yourself from walking over to the right shelf…
Post: Percona Replication Manager, a solution for MySQL high availability with replication using Pacemaker
November 29, 2011 By 102 Comments
… Pacemaker is its flexibility but flexibility may results in complexity. With the help of people … this solution PRM for Percona Replication Manager. All the parts are opensource and available under …passwd: The credentials to test MySQL. Default is to run select count(*) on mysql.user table, so the …
