Ralf Haferkamp wrote:
Am Freitag 01 Mai 2009 11:50:15 schrieb [email protected]:
Hi,
since quite some time libldap enables tcp-keepalive, e.g. to detected
dangling
syncrepl connections. However the default timeout of two hours that most
systems are using might be a bit too long for some applications (e.g. I
had a
problem lately were nscd didn't answer queries anymore because nss_ldap
was
blocking in SSL_read() while the underlying connection has been cut off).
On
the other hand messing with the system wide settings might no be a good
idea
either. On Linux it is possible to configure the keepalive settings on a
per
socket basis through the TCP_KEEP* socket options.
Would it be worth adding ldap_set_option() support for those, even if
they are
not really portable?
I think it would; for archs that do not support it, it could do nothing
(and log accordingly, just in case).
Ok, I'll introduce the following new options for keepalive support then:
LDAP_OPT_X_KEEPALIVE_IDLE 0x6300
LDAP_OPT_X_KEEPALIVE_PROBES 0x6301
LDAP_OPT_X_KEEPALIVE_INTERVAL 0x6302
We might also think about adding support to set those values for syncrepl and
back-ldap/back-meta.
I'd prefer a portable solution vs something so extremely platform-dependent.
As already discussed many times before, we just need a client to send a
periodic LDAP no-op message to get the same effect. (Abandon 0 will work
fine.) While it's not as general purpose as setting a keepalive in the socket
layer, I think we only need to worry about the syncrepl client. back-ldap/meta
already have their own retry mechanisms, they can take care of themselves.
So - I'd rather see an option for a periodic LDAP ping added to the syncrepl
client - that will work uniformly across all platforms.
And in general - I am opposed to any code that causes our feature set /
behavior to differ from platform to platform.
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/
