On 2/4/11 10:58 PM, Stefan Seelmann wrote:
Hi guys,
one of our Hudson builds currently fails [1], the cause is an
IOException (Too many open files). The reason this happens is that in
our integration test (server-integ and ldap-api-test) we open real
network connections. In many cases a new connection is opened in each
test method. I also found a case where we open new connections within
a loop.
I added some performance tests for each operation, but those tests are
@Ignored.
What is the tests containing a loop ?
Most times the connections is closed after usage. However, as you
certainly know, there is still a problem with allocating many new
connections: sockets remain in TIME_WAIT state for some time after
bein closed, see [2]. On the Hudson servers we can of course increase
the ulimit -n and reduce the TIME_WAIT value. But I think that won't
scale when connections are opened in a loop.
Sure. We can also ask to have short lived socket, like 5 secs. Usually,
a socket remain in TIME_WAIT state for 30 secs on a standard linux box.
I'd like to discuss possible options to improve the situation:
- Fist I think in general we should avoid to create new connections
within a loop in integration tests. We have other techniques to run
such test [3]. In general such test patterns are stress or performance
tests, but not integration tests.
+1
- Second we should avoid to create a new connection for each test
method. One option to achieve this is to use a single connection per
test class without opening/closing them @Before/@After each test.
Maybe the better option is to use a connection pool. Of course when
testing connect/disconnect/bind/unbind it may be required to use a
fresh connection objects.
If we use our client API, we have to add a pool into the API. In the
tests where we use JNDI, we can use a pool, that's for sure.
--
Regards,
Cordialement,
Emmanuel Lécharny
www.iktek.com
