Re: [Sqlrelay-discussion] MySQL Load Testing

[David M. <dav...@fi...>]

On Wed, 2 Mar 2005 10:16:12 -0000
Marvin Wright <MW...@la...> wrote:

> Hi David,
> 
> Thanks for the reply, I think you are right.
> I did some tests using only 50 clients and its consistenly very fast.
> 
> I think I will have to re-configure some of my pools so I can increase
> the connections in a particular pool as its quite possible that I may
> have 300 concurrent client connections.  Is there any limit in
> sqlrelay on pool size?  I guess the limit will be at the database
> size.

The limit of the pool size would depend on the number of concurrent
connections that the database can support and the amount of ram on the
server running SQL Relay.

> 
> Just to be sure, doing a con->endSession() gives back the session.
> I want to make sure I'm returning sessions to the pool as fast as I
> can.

That's correct.

> 
> Regards,
> 
> Marvin. 
> 
> -----Original Message-----
> From: sql...@li...
> [mailto:sql...@li...] On Behalf Of
> David Muse
> Sent: 25 February 2005 15:39
> To: sql...@li...
> Subject: Re: [Sqlrelay-discussion] MySQL Load Testing
> 
> It really sounds like the bottleneck is a case of clients waiting on
> available connections.
> 
> The client doesn't actually log into the SQL Relay server until the
> first query is run, so even if it's bottlenecked waiting on an
> available connection, the client will stall out during the call to
> sendQuery.
> 
> When it's running slowly, take a look on the server and see if there
> aren't a bunch of sqlr-listener processes.  If there are, then most of
> them are holding on to client connections, waiting for an available
> database connection.
> 
> You could try load testing 50 clients and see how that runs.  I'd
> expect it to be fast.  Then, as you add more clients, it should slow
> down.  If it follows this pattern, then the slowdown must be due to
> clients waiting for available connections.  If it still runs slowly
> with 50 or fewer clients, then something else is going on.
> 
> Dave
> 
> On Mon, 14 Feb 2005 09:52:21 -0000
> Marvin Wright <MW...@la...> wrote:
> 
> > Hi David,
> > 
> > I'm having some issues while doing some load tests with sql relay.
> > 
> > I have a pool of 25 connections that may grow to 50 and I have 
> > assigned 50 cursors to the pool.
> > 
> > I've built a server application that uses this pool to connect to a 
> > local cache of data.
> > 
> > If I execute 1 request to my server app it returns a sub second 
> > response.
> > 
> > Now when load testing all the way to 300 concurrent requests the app
> > starts returning response of upto 10 seconds.
> > I've done some program tracing and filled the app with plenty of
> > logs, I seem to get a bottle neck on the actual sendQuery.
> > Some of these queries are taking 9 seconds to execute.  I'm also 
> > monitoring the database, the queries that are run are all under a 
> > second. The slow down seems to be somewhere in the sendQuery but 
> > that's all I can tell.
> > 
> > I thought at first that with only 50 max connections to the pool
> > that the threads might be waiting for a connection but it does seem
> > to be the case.
> >
> > If I switch access to this local cache off load-testing all the way
> > to 500 connections my app will return all connections under 2
> > seconds.
> > 
> > I'm running the new pre-release version 3 of sql relay.
> > 
> > Any ideas what may be the problem or what I can try ?
> > 
> > Many thanks.
> > 
> > 
> > Marvin Wright
> > Flights Developer
> > Lastminute.com
> > mw...@la...
> > +44 (0) 207 802 4543
> > 
> > 
> > 
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