Inconsistent output of 'mogadm domain list' encountered

[dormando]

Fixed both instances in trunk...

They were trivial changes (although I put the cache clear in a different
place), but I might not have totally understood the original goals of
the singleton caches. Feel free to berate my fail :)

Also haven't figured a decent test, since the issue tends to happen in
parallel processes. Any ideas?

-Dormando

Frank Ng wrote:
> We see the same thing in our test mogilefs env.  i made a change of
> mindevcount from 2 to 3 and ran mogadm class list a few times, it's show
> alternating results.
>  
> [root at xxx mogdata]# mogadm class list
>   domain               class                mindevcount
> -------------------- -------------------- -------------
>  snf_test01           default                   2
>  snf_test01           snf_hr                    2
>  snf_test01           snf_lr                    3 <--
>  
> [root at xxx mogdata]# mogadm class list
>  domain               class                mindevcount
> -------------------- -------------------- -------------
>  snf_test01           default                   2
>  snf_test01           snf_hr                    2
>  snf_test01           snf_lr                    2 <--
>  
> [root at xxx mogdata]# mogadm domain list
>  domain               class                mindevcount
> -------------------- -------------------- -------------
>  snf_test01           default                   2
>  snf_test01           snf_hr                    2
>  snf_test01           snf_lr                    2 <--
>  
> [root at xxx mogdata]# mogadm domain list
>  domain               class                mindevcount
> -------------------- -------------------- -------------
>  snf_test01           default                   2
>  snf_test01           snf_hr                    2
>  snf_test01           snf_lr                    3 <--
> 
>  
> On Wed, Mar 12, 2008 at 3:58 AM, Chaos Wang <chaoslawful at gmail.com
> <mailto:chaoslawful at gmail.com>> wrote:
> 
>     Hi,
> 
>     I use the MogileFS code from official svn trunk to do some test. But
>     when I do some domain addition/deletion operations, the output of
>     'mogadm domain list' becomes inconsistent between different calls.
>     This phenomenon can be repeated by following steps:
> 
>        1. mogadm domain add xxx
>        2. mogadm domain delete xxx
>        3. mogadm domain add yyy
>        4. mogadm domain list (several times)
> 
>     I thinks the problem is in the invalidate_cache() method in
>     MogileFS::Domain module, because it forget to clean up the hash map
>     %singleton (of_dmid(), which is called in domains(), used this hash
>     map before trying %id2name map). After made the following changes in
>     MogileFS::Domain::invalidate_cache(), the phenomenon doesn't show up
>     again:
> 
>     --code begin--
>     sub invalidate_cache {
>     ...
>     %id2name=();
>     %name2id=();
>     %singleton=(); # XXX: this is newly added
>     ...
>     --code end--
> 
>     And I have another question: does classes belong to certain domain?
>     If so, why delete a domain does not clean up the classes under it?
> 
>