Emergency

Search Results for: mysql explain eq_ref ref

Another look at improving TPC-H-like queries – Q17

Summary: An alternate approach, offered in response to our original post, provides excellent improvements for smaller databases, but clustered indexes offer better performance as database size increases. (This posting is by Dave.) Jay Pipes suggested …

Read More
 

Improving TPC-H-like queries – Q17

Executive Summary: A query like TPC-H Query 17 can be sped up by large factors by using straight_joins and clustering indexes. (This entry posted by Dave.) In a previous post, we wrote about queries like …

Read More
 

Improving TPC-H-like Queries – Q2

Posted by Bradley C. Kuszmaul and David Wells Executive Summary: A MySQL straight join can speed up a query that is very similar to TPC-H Q2 by a factor of 159 on MySQL. Recently, we …

Read More
 

JOIN Performance & Charsets

We have written before about the importance of using numeric types as keys, but maybe you’ve inherited a schema that you can’t change or have chosen string types as keys for a specific reason. Either …

Read More
 

Enum Fields VS Varchar VS Int + Joined table: What is Faster?

Really often in customers’ application we can see a huge tables with varchar/char fields, with small sets of possible values. These are “state”, “gender”, “status”, “weapon_type”, etc, etc. Frequently we suggest to change such fields …

Read More
 

MyISAM Scalability and Innodb, Falcon Benchmarks

We many times wrote about InnoDB scalability problems, this time We are faced with one for MyISAM tables. We saw that several times in synthetic benchmarks but never in production, that’s why we did not …

Read More
 

Merge Tables Gotcha

I had the interesting customer case today which made me to do a bit research on the problem. You can create merge table over MyISAM tables which contain primary key and global uniqueness would not …

Read More