"howa" <howachen@gmail.com> wrote:
> Axel Schwenke =BCg=B9D=A1G
>> "howa" <howachen@gmail.com> wrote:

>> > for example, MySQL replication is not suitable for scable application
>> > which need many writes, e.g. a popular forum
>> >
>> > ao are there any recommendation in this suitation?
>>
>> InnoDB on big hardware (lots of memory and fast disks).
>> If that does not work out (unlikely) - MySQL Cluster.

> thanks for your reply first, i have two questions:
>
> 1. Did MySQL has some benchmark that could give a general picture on
> the performance of MySQl, such as on a dual processor 3Ghz Xeon, 4GB
> memory, 15k RPM HD setup, it can handle xxx write/read transeactions
> per second?

Some Benchmarks are available from the MySQL website:
http://www.mysql.com/why-mysql/

Also Peter Zaitsev (former MySQL employee) blogs about performance:
http://www.mysqlperformanceblog.com/

When we are talking about InnoDB and write performance - the bottleneck
is usually the disk where the transaction log is written. Each COMMIT
requires to physically flush the log. This is equivalent to at least
one I/O operation. The I/O throughput of disks (that is: I/O operations
per second, not number of transferred blocks per second) is dominated
by head moving time and rotational delay. A 15Krpm disk will achive
150-200 I/O ops per second.


> 2. Is Cluster the last option?

Cluster was designed for *really* write heavy applications. I.e. Telcos
doing logging and accounting for millions of users. MySQL Cluster can
do several 1000 writes per second. This is much more than what I would
expect from even a very popular forum.

> What would be the drawback if both
> InnoDB & Cluster work for me, but I chose to use Cluster besides it
> will be difficult to setup?

MySQL Cluster is an in-memory storage engine. That is: all data is kept
in RAM. Of course this will get expensive very soon.


XL
--
Axel Schwenke, Senior Software Developer, MySQL AB

Online User Manual: http://dev.mysql.com/doc/refman/5.0/en/
MySQL User Forums: http://forums.mysql.com/