Re: [Hsqldb-user] hsql 2.0 performance with many connections

[Fred T. <fr...@us...>]

Traditional databases such as PostgreSQL use a limited number of worker
threads internally to perform the tasks submitted by client connections.
In contrast HyperSQL (the name is not Hypersonic) allocates a separate
active thread for each connection.

Therefore using very many connections that are active at the same time
adds internal management overheads. Overheads are less when only a few
of the open clients connections are active at the same time. Overheads
should also be less in MVCC mode, compared to the default LOCKS mode.

We have worked to reduce the overheads since version 2.0.0 and will
continue this work in future versions.

In the meantime, you should consider if your test reflects the real life
load conditions accurately. In most real life use cases the load is not
distributed evenly in time. 
 
Fred

On Fri, 06 May 2011 10:01 +0200, "Andrea Manca" <ma...@li...> wrote:
> Hi all
> 
> I'm running some stress test on my web application. it's using 
> Hypersonic 2.1.0  as backend, which listen in a separate machine, and 
> using cached tables.
> 
> In my test each client invoke a web service which in turn insert some 
> datas into DB. In fact to each client correspond a db connection.
> 
> I've measured the request per second obtained from the test client, 
> gradually increasing the client number, and in correspondence of 600 
> concurrent clients, i measured a marked decrease of perfomance.
> 
> The same level of degradation does not occur by repeating the test with 
> a different database (Postgresql 8.4)
> 
> 
> Someone knows how to tune hsql 2 to support a high connections number 
> environment ?
> 
> -- 
> Andrea Manca
> Link.it s.r.l - www.link.it
> ma...@li...
> 
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