Core dumping DLZ

[Scott Haneda]

On May 7, 2009, at 9:50 PM, Mark Andrews wrote:

> 	I beg to differ.  Named only gets to this position in the
> 	code if it has been told to shut itself down.  Note this
> 	may happen as a side effect of shutting the machine itself
> 	down.


I can say with a lot of confidence, the machine is not being shut  
down.  Not 100% though, I will certainly look into improving that  
percentage.  I peeked in the logs for messages, wtmp, secure, and  
boot, which did not yield anything that would lead me to think a  
reboot was happening.

Could it be that if SBD/DLZ gets into bad shape, that is causing the  
terminate?

I turned on mysql query logging and watched it for a while, seeing  
three queries come in that were suspicious.

090508  3:09:34	     24 Query       SELECT zone FROM resource_records
					WHERE zone = 'www.a.com'
		     24 Query       SELECT zone FROM resource_records
					WHERE zone = 'a.com'
		     24 Query       SELECT zone FROM resource_records
					WHERE zone = 'com'

That is the result of one dig:
dig  www.a.com @ns1.example.com SOA

Taking the further, I made a more extreme test, which only moments  
later, generated a core file, though this time, DNS managed to stay up  
and answer questions...

* At some point in time later, queries will not get answers unless I  
restart named-sdb manually.

* After this core was made, named-sdb is unable to answer queries, for  
mysql driven data, or file based zones.  However,  named-sdb is still  
running:

$ ps aux | grep named | grep -v grep
named     4918  0.0  0.1 199188 20528 ?        Ssl  02:56   0:00 /usr/ 
sbin/named-sdb -u named

This one dig causes 26 total lookups, which is pretty strange in and  
of itself.
dig a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com  
@ns1.example.com SOA

SELECT zone FROM resource_records WHERE zone =  
'a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'd.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'm.n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'n.o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'o.p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone =  
'p.q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 'q.r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 'r.s.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 's.t.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 't.u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 'u.v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 'v.w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 'w.x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 'x.y.z.com'
SELECT zone FROM resource_records WHERE zone = 'y.z.com'
SELECT zone FROM resource_records WHERE zone = 'z.com'
SELECT zone FROM resource_records WHERE zone = 'com'

Thanks for your suggestions, I appreciate it.  Has anyone else managed  
to get mysql and named-sdb running solid on RHEL?
-- 
Scott * If you contact me off list replace talklists@ with scott@ *