Selon Behrang Saeedzadeh <behr...@gmail.com>:
Mathias,
Thanks a lot!
I will not explain the same thing for sqlserver, sybase ..., but when
your RDBMs
have a data dictionnary, you don't need to execute count(*) :o) WITH
Updated
statistics of course.
I'm a little bit confused here. Why the count(*) is not transformed to a
select from the data dictionary if this way is faster? And what's the
difference between updated statistics and statistics not updated?
With information_schema in 5.x and higher, innodb will act as it's done
in all
the other RDBMS.
Hope that helps
Sure! It helped by orders of magnitured more than I thought it can help ;-)
Using Opera's revolutionary e-mail client
Well,
The information in data dictionnary are correct only just after updating them.
imagine at 12h, you update statistics, num_rows=2000. At 12h05, you insert 1000
lignes and delete 500.
At 12h10, you ask the data dictinary num_rows, it will give you 2000, even if
they are 2500.
8 messages in com.mysql.lists.mysqlRe: A question about the select count...