So lets say you have .frm file for the table and you need to recover CREATE TABLE statement for this table. In particular when we do Innodb Recovery we often get .frm files and some mess in the Innodb tablespace from which we have to get data from. Of course we could relay on old [...]
Four ways to optimize paginated displays
September 24, 2008 By 27 Comments
A paginated display is one of the top optimization scenarios we see in the real world. Search results pages, leaderboards, and most-popular lists are good examples. You know the design pattern: display 20 results in some most-relevant order. Show a “next” and “previous” link. And usually, show how many items are in the whole list [...]
AUTO_INCREMENT and MERGE TABLES
September 11, 2008 By Leave a Comment
How would you expect AUTO_INCREMENT to work with MERGE tables ? Assuming INSERT_METHOD=LAST is used I would expect it to work same as in case insertion happens to the last table… which does not seems to be the case. Alternatively I would expect AUTO_INCREMENT to be based off the maximum value across all tables, respecting [...]
Picking datatype for STATUS fields
August 9, 2008 By 24 Comments
Quite commonly in the applications you would need to use some kind of “status” field – status of order – “new”, “confirmed”, “in production”, “shipped” status of job, message etc. People use variety of ways to handle them often without giving enough thought to the choice which can cause problems later. Perhaps worst, though quite [...]
Using MMM to ALTER huge tables
March 27, 2008 By 11 Comments
Few months ago, I wrote about a faster way to do certain table modifications online. It works well when all you want is to remove auto_increment or change ENUM values. When it comes to changes that really require table to be rebuilt – adding/dropping columns or indexes, changing data type, converting data to different character [...]
MySQL Blob Compression performance benefits
January 11, 2008 By 17 Comments
When you’re storing text of significant size in the table it often makes sense to keep it compressed. Unfortunately MySQL does not provide compressed BLOB/TEXT columns (I would really love to have COMPRESSED attribute for the BLOB/TEXT columns which would make them transparently compressed) but you well can do it yourself by using COMPRESS/UNCOMPRESS functions [...]
Using index for ORDER BY vs restricting number of rows.
February 16, 2007 By 8 Comments
One interesting problem with MySQL Optimizer I frequently run into is making poor decision when it comes to choosing between using index for ORDER BY or using index for restriction. Consider we’re running web site which sell goods, goods may be from different categories, different sellers different locations which can be filtered on, and there [...]
Database access Optimization in Web Applications.
September 12, 2006 By 10 Comments
This is pretty simple approach I often use called to optimize web application performance if problem happens with few pages. If we have “everything is slow” problem looking at slow query logs may be better start. So what could you do ? Look at the information shown on the page which comes from database. This [...]
