Intermittent etwork connection errors with apache. Restarting apachetemporarily fixes the problem.

Hi - At the top of my php scripts, I have code to connect to our ldap
server, in order for the scripts to make ldap requests. I don't have
any disconnect call in my code. Lately I have noticed that the apache
server will get into a state where connection requests will occasionally
fail. When I refresh the page, the connection almost always succeeds on
the 2nd attempt. If I restart the apache server, the problem totally
goes away for a long period of time. So I assume that somewhere,
something is causing connections to stay opened when the script ends,
rather than automatically closing them.

This error occurs with other types of network connections that the
script makes (besides ldap), so it's not an ldap issue.

How does Apache automatically close connections when the script ends?
Is it possible that connections are being left opened? Is there any way
to debug the problem, i.e. to see if connections are left opened in some
way?

I'm running redhat 5, httpd-2.2.3-31.el5_4.2 php-5.1.6-23.2.el5_3

Thanks. - Mark



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Re: Intermittent etwork connection errors with apache. Restarting apache temporarily fixes the prob

Hi Mark,


> I don't have any disconnect call in my code. =20

Is this the same for all your connections code, apart from your LDAP? =
It's good practice to never assume that PHP will disconnect connections =
for you - explicitly call the disconnect function when your connection =
is done with.

> Lately I have noticed that the apache server will get into a state =
where connection requests will occasionally fail. When I refresh the =
page, the connection almost always succeeds on the 2nd attempt. If I =
restart the apache server, the problem totally goes away for a long =
period of time. =20

Are you talking about the connection to Apache or the connection from =
your Apache server to your other servers?

> So I assume that somewhere, something is causing connections to stay =
opened when the script ends, rather than automatically closing them.

As I said above, always explicitly disconnect from any services you =
connect to when you're finished.

>=20
> This error occurs with other types of network connections that the =
script makes (besides ldap), so it's not an ldap issue.
>=20
> How does Apache automatically close connections when the script ends? =
Is it possible that connections are being left opened? Is there any way =
to debug the problem, i.e. to see if connections are left opened in some =
way?

Run "netstat -an|grep tcp" on the server's console before and after a =
page request - if possible prevent all other connections to your Apache =
server while you do it.

Connections that remain open will be in the state "ESTABLISHED" - server =
processes (e.g. Apache) will be listed as "LISTEN."

If you get an LDAP connection after your page request that wasn't there =
before in the ESTABLISHED state, PHP isn't disconnecting.

If any connections are listed as TIME_WAIT, it means the connection was =
dropped without the client disconnecting properly - it may be worth =
running netstat on your LDAP server as well.

Regards,
Andy=

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