Hack hack hack...

An open journal-- some of it written for you, but most of it is for me.

SQL DB Talk From CTO of Behance

Thanks to Chris Henry for taking the time to come down

Things examined

lock_time the time the server will wait

rows examined

tmp_tables - creating these temp tables are bad

cartisan product

indexes- once you created them run completed under the hood can only use one index per table

Review: Query execution plan more reading

  • only way to get around this is to change the structre– i.e. denormalization


  • cost per write -> re-indexing
  • Can use indexes to set constraints on your data

Cardinality : how chunky your data is

SELECT COUNT(*) title FROM tags t INNER JOIN tags_entity_links tel ON t.id = tel.tag_id WHERE category = 1 AND title

The tags are polymorphic: tag table id | tag_id | id_for_table | type

performance to denormalization ??performance or aggregate data

composite index

LEFT JOIN or RIGHT JOIN will show the nulls that wouldn’t be included in INNER JOIN

The NoSQL camp is a return to hierarchical data stores - a 40 year old

count or cache

three seperate databases = 3 apps


apache bench
watch the slow logs
cacti tool
load on the server


?? why mysql over postgres?

  • right place right time


  • percona port makes the most sense for mysql-

?? many proj has many tags - many to many - goes through what join table?

Look up:

  • jumping words in the terminal