Re: How to speed up the answer time ?

[Mikael Ronström]

Hi,

Jörg Nowak wrote:
> Hello everybody,
>
> we did in the last few weeks some performance
> tests with the cluster (2 servers (each has 2 CPU)
> 4 GB RAM, 4 DB nodes, 1 million customer profiles
> in the database).
>
> we stressed the database with up to 100 clients,
> which sends so much requests (reads and writes) as
> they can. The cluster served aprox. 2500 requests
> per second, which is ok for us (in theory less
> than 0,5 ms for one request).
> But the problem is the answer time from the client
> side for a single request. The cluster can not
> guaranty a answer to a single request in a few
> (better less than one) milliseconds. We measured
> answering times up to 50 ms and more for a single
> request from a single client. This is not
> acceptable for our project.
> We did not optimize config parameters and the
> mysqld is on the same machines like the cluster.
>
> How can we speed up the answer time from the
> client side. What could be the bottle neck ? Our
> impression was that the mysqld had a lot of
> stress. Is it possible to run more than one mysqld
> on each server in the cluster ? Are there config
> parameter to speed up ?
>

One fix has been pushed that decreases response time for certain queries
significantly has been pushed into 5.0. One parameter exists also which can
be set as a connection parameter.

This is:
SET NDB_FORCE_SEND;
This parameter will send off all requests to NDB immediately and will thus keep
response time to a minimum at a possible cost of extra CPU cycles.

If you can give a hint on the type of queries I can also provide a hint on which
optimisations might be possible.

Rgrds Mikael
PS: There are some more development work in this area ongoing so any feedback on
your particular problem is helpful.

> Thanks in advance.
>