On Mar 23, 2009, at 10:30 AM, Daniel Carrera wrote:
Could you confirm that row-level locking means that you can do multiple INSERTs at the same time?
Suppose that you are going to do 50 INSERTs in one transaction (my non-Drupal site does this at one place). Can two users do the 50- INSERT operation at the same time? (the application is a markbook/ gradebook - the inserts are the marks/grades for 50 students).
Well there are some gotcha conditions, if you have a WHERE clause in your update, it must be using an index, otherwise it has to do a table scan, and locks the whole table. Also, any inserts using an auto- increment column will lock the entire table to prevent duplicate values.
I thought that InnoDB was supposed to be faster for reading. At least, for reading rows that are related by index (e.g. users 1-20 assuming that "user id" is an index).
Please see http://2bits.com/articles/mysql-innodb-performance-gains-as-well-as-some-pit... for some examples.
-Mike
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