… lot of people arrived with some uncertainty about how it would turn out, but the doubts didn’… few months, without momentum, and we had to work with the space and dates that were available. … keynotes are available on percona.tv for your viewing pleasure anytime. Sheeri Cabral also recorded some of …
Post: How to find wrong indexing with glance view
August 21, 2008 By 27 Comments
Quite common beginners mistake is not to understand how indexing works and so index all columns used in the queries…. separately. … single column ones. This can be spotted with a glance view. If you have queries with multiple column restrictions in WHERE…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 12 Comments
… working with the Flexviews easier, it includes a script called ‘convert.php’. This script makes it easy to create incrementally refreshable views… The first parameter to flexviews.refresh() is the materialized view id. Each view has an identifier which can be obtained with flexviews… also showed how you can combine both types of views together. The complete method examples show how to create a complete refresh view which…
Post: MySQL VIEW as performance troublemaker
August 12, 2007 By 53 Comments
… with complexity hidden away in VIEW definition. Just another day I worked on optimizing application which uses VIEWs and was looking at the… not work. It is interesting to see EXPLAIN for such query and time for the query which fetches everything from the VIEW… create a very artificial query which will JOIN 2 views just to see how indexes are used: mysql> explain select uc.cnt…
Post: Using Flexviews - part one, introduction to materialized views
March 23, 2011 By 2 Comments
… processing can be done on a slave dedicated to such work. And some drawbacks: Not all SQL syntax supported (no outer… the views. These capabilities break down into three main categories which will be blogged about in subsequent posts: Change Data Capture – How… as an ELT* tool and it will cover how to create the materialized views which Flexviews manages. *ELT – extract, load and transform…
Post: Using VIEW to reduce number of tables used
September 28, 2007 By 12 Comments
… to the same table as VIEWs are significantly less expensive and cheap to “open”. How this could work ? Say you have “post” tables… we do not insert data in the view which will be invisible. The VIEW approach works for SELECT, UPDATE, DELETE queries but not… to default, which does not work as it has to be different for each of the views. You could think MySQL would…
Post: MySQL opening .frm even when table is in table definition cache
November 21, 2011 By 8 Comments
… three years ago to the day. Since we completely reworked how metadata works in Drizzle, it has enabled us to do some… over four minutes to execute and get a more complete view of how the Storage Engine API is called. But back to… example of how this is used is that in the DROP TABLE code path, MySQL uses this magic byte to work out…
Post: Using Flexviews - part two, change data capture
March 25, 2011 By 11 Comments
…performance by identifying the data which has changed. Maintain materialized views with Flexviews (the primary purpose of FlexCDC). Feed search …aforementioned problems. The biggest problem, at least from standpoint of how Flexviews works, is that triggers can not, under normal conditions, detect…
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
… – Meaning it does not work for subselects, inline views, parts of the UNION. This is also common missunderstanding. Works on packet level – This… as a lot depends on statement complexity as well as how much work is saved by query cache. Now lets speak a… can’t change how it works with MySQL to add caching but you can enable query cache so it works faster. Low load…
Post: Just do the math!
July 6, 2009 By 4 Comments
… page views a day you few days of history the queries there instant which gave you a confidence this approach will work… the whole year worth of data you find things not working any more with response times for individual queries taking half… (or say apply mathematical model) you really need to understand how things work. I like to call it having X-Ray vision…
