Victor Duchovni:
> On Mon, Aug 31, 2009 at 01:40:34PM -0400, Wietse Venema wrote:
>
> > > We just pass a list of servers to the LDAP library.
> > >
> > > Perhaps the simplest enhancement would be to "rotate" the server list
> > > when a query times out, before asking the LDAP library to re-connect.
> > >
> > > server-list before time-out: s1 s2 ... sN
> > > server-list after time-out: s2 ... sN s1
> > >
> > > Any other suggestions?
> >
> > Reversing the list may get a quicker recovery when there are more
> > than 2 servers, and the time-out happens somewhere in the middle.
> >
> > When there are 2 servers, then rotating is equivalent to reversing.
>
> I am reluctant to reverse the list, because this gives us only two
> possible orders (as opposed to N orders with N elements), and we are I
> think promising the user to use servers in the order specified.
>
> The rotate code is simple:
>
> Index: src/global/dict_ldap.c
> --- src/global/dict_ldap.c 27 Apr 2009 03:36:00 -0000 1.1.1.1
> +++ src/global/dict_ldap.c 31 Aug 2009 18:07:17 -0000
> @@ -570,7 +570,26 @@
>
> #endif
>
> -/* Establish a connection to the LDAP server. */
> +/* dict_ldap_rotate - rotate server list */
> +
> +static void dict_ldap_rotate(DICT_LDAP *dict_ldap)
> +{
> + char *s = dict_ldap->server_host;
> + char *s1 = mystrtok(&s, " "); /* SPC separated post initial parse */
> +
> + /*
> + * If more than one LDAP server specified, rotate the first one to the
> end
> + * of the list.
> + */
> + if (*s) {
> + s = concatenate(s, " ", s1, (char *)0);
> + myfree(dict_ldap->server_host);
> + dict_ldap->server_host = s;
> + }
> +}
> +
> +/* dict_ldap_connect - Establish a connection to the LDAP server. */
> +
> static int dict_ldap_connect(DICT_LDAP *dict_ldap)
> {
> const char *myname = "dict_ldap_connect";
> @@ -620,6 +639,13 @@
> dict_errno = DICT_ERR_RETRY;
> return (-1);
> }
> +
> + /*
> + * The current connection has just saved the server list.
> + * Rotate the server list for any future connection attempts.
> + */
> + dict_ldap_rotate(dict_ldap);
> +
> mytimeval.tv_sec = dict_ldap->timeout;
> mytimeval.tv_usec = 0;
> if (ldap_set_option(dict_ldap->ld, LDAP_OPT_NETWORK_TIMEOUT, &mytimeval)
> !=
This looks like unconditional rotation after non-error?
Wietse
