… to the table metadata, a table ALTER that alters a big table can keep executing without any hindrance, copying rows from the table with the old structure to the table… that no table open operation was performed and hence no wait. Does the fact that the table has already been opened and table object…
Post: Troubleshooting MySQL Upgrade Performance Regressions
February 15, 2012 By Leave a Comment
… Percona Server 5.5 and instead of expected performance improvement you see your performance being worse. What should you do ? First if… especially be helpful. Once you have spotted the query which performs differently between MySQL Server versions you should: Check Query Plan…_JOIN, FORCE INDEX, BIG_RESULT/SMALL_RESULT. Check whatever stats are the same (run SHOW INDEXES FROM for tables involved and check…
Post: Performance impact of complex queries
January 17, 2007 By 11 Comments
What is often underestimated is impact of MySQL Performance by complex queries on large data sets(ie some large … if you use Innodb tables and so do not suffer from table locks reporting queries can affect web site performance dramatically. Sometimes instead… chop it, meaning do not do it as all one big simple query or as set of queries going one after…
Post: MySQL on Amazon RDS part 1: insert performance
March 15, 2011 By 37 Comments
… cloud-hosted MySQL solution. I’ve had some clients hitting performance limitations on standard EC2 servers with EBS volumes (see SSD… 400,000,000 rows. This creates a table+index data size approximately twice as big as memory, so the workload should be somewhat IO-bound. My goal for this benchmark is long-term performance, but…
Comment: Why MySQL could be slow with large tables ?
November 21, 2009 By 141 Comments
… table down into tables by week. My question is what my plan of attack should be to get the best insert performance? MERGE tables? PARTITION tables? Simply break up my big table into smaller ones? I think the root…
Post: Handling big result sets
June 26, 2006 By 13 Comments
… are common or similar for all APIs, including C). Consider table: CREATE TABLE `longf` ( `f1` int(11) NOT NULL auto_increment, `f2…’) or die(‘Could not select database’); $time_start = microtime(true); // Performing SQL query $query = ‘SELECT * FROM longf’; $result = mysql_query($query… it could be opposite. Prepared statements are typically considered for performance reasons if statement needs to be executed several time – as…
Comment: Why you don't want to shard.
October 20, 2012 By 34 Comments
… a question, I have a very big table and I want to shard it into five tables, but I only have one host… to split my table into five table and split my data according to userId key. Does it improve database performance for INSERT and… know that if I spread my data on multiple host, performance would improve but what in my case? Thanks a lot
Post: Analyzing air traffic performance with InfoBright and MonetDB
October 2, 2009 By 50 Comments
….32.2 LucidDB was 0.9.1 The table I loaded data is: CREATE TABLE `ontime` ( `Year` year(4) DEFAULT NULL, `Quarter… did not understand how to do that, so I generated big SQL file which contained load statements. Load of each chunk… if you want to compare or get info about air performance.
Post: Using VIEW to reduce number of tables used
September 28, 2007 By 12 Comments
… OF triggers so you could write triggers to perform insert inserts to base tables instead of views. BEFORE INSERT triggers would not… in the base table – generally there should be only few places when insert happens so it should not be big problem. Technically if you can’t make inserts to the base table but can have them going to the different table…
Post: Using flow control functions for performance monitoring queries
May 24, 2008 By 12 Comments
I’m not big fan on flow control functions like IF or CASE used … like to use it for web site performance analyzes. As you can see in this table we have recorded “wtime” which is… but may be less used functions performance problems. Another thing you may notice I look for performance stats not for all pages…
