… SQL query $query = ‘SELECT * FROM longf’; $result = mysql_query($query) or die(‘Query failed: ‘ . mysql_error()); // retrive result while ($line = mysql_fetch_array($result…: mysql_unbuffered_query() sends a SQL query query to MySQL, without fetching and buffering the result rows automatically, as mysql_query() does…
Post: Using GROUP BY WITH ROLLUP for Reporting Performance Optimization
September 17, 2007 By 12 Comments
… of extra temporary table for buffering helps us to get result set we’re looking for and workaround this limitation, though… completing in 30 seconds rather than 40. Though fetching all result set in this case is still significantly faster. So GROUP… I forced FileSort execution method for GROUP BY by using SQL_BIG_RESULT hint I can see GROUP BY executing about same time…
Post: Are larger buffers always better ?
June 6, 2006 By 9 Comments
…=MyISAM DEFAULT CHARSET=utf8 select sql_no_cache count(*) from t1 where c in (select sql_big_result count(*) from t1 where d=50… ahead and set them to 64M ? Not really – this could result in nasty suprises with full table scan LIMIT queries as…
Post: MySQL Session variables and Hints
December 28, 2006 By 2 Comments
… execution of particular query. First is MySQL Hints, such as SQL_BIG_RESULT, STRAIGHT_JOIN, FORCE INDEX etc. You place these directly into… query is executed, so I could do something like: SELECT SQL_SORT_BUFFER_SIZE=50000000 NAME FROM LARGE_TABLE ORDER BY…
Comment: Why MySQL could be slow with large tables ?
June 19, 2006 By 139 Comments
… of resulting rows is large you might get pretty poor speed because temporary table is used and it grows large. Using SQL_BIG_RESULT…
Comment: Why MySQL could be slow with large tables ?
April 12, 2007 By 139 Comments
…. It’s losing connection to the db server. I tried SQL_BIG_RESULT, analyze table, etc… nothing seems to help Here’s my…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… sql_auto_is_nullblogpercona.commanual sql_big_selectsblogpercona.commanual sql_big_tablesblogpercona.commanual sql_buffer_resultblogpercona.commanual sql_log_binblogpercona.commanual sql_log_offblogpercona.commanual sql_log_updateblogpercona.commanual sql_low_priority_updatesblogpercona.commanual sql…
Post: Checking for a live database connection considered harmful
May 5, 2010 By 38 Comments
… design pattern, written in pseudo-code: function query_database(connection, sql) if !connection.is_alive() and !connection.reconnect() then throw exception… like this: function query_database(connection, sql, retries=1) while true try result=connection.execute(sql) return result catch InactiveConnectionException e if retries > 0… find and solve these issues, because it’d be a big help to apps when they grow. It’s one of…
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
…the new SpecJAppServer Results More information from Tom Daly can be found here These results are quite …in /etc/my.cnf (included in FDA) [mysqld] sql-mode = IGNORE_SPACE transaction-isolation = READ-COMMITTED …cache_size = 0M – query cache disabled. Not a big surprise though as this is default value …
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…query parallelization, so ETL jobs written to rely on SQL tend to get really bogged down. In contrast,… doing the work on a slave, then piping the results back up to the master with LOAD DATA INFILE,… nested-loop joins are not all that fast on big joins; the query optimizer can sometimes pick bad …
