diff options
Diffstat (limited to 'system/doc/design_principles/sup_princ.xml')
| -rw-r--r-- | system/doc/design_principles/sup_princ.xml | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/system/doc/design_principles/sup_princ.xml b/system/doc/design_principles/sup_princ.xml index 2748f21bbe..7ad007d3fd 100644 --- a/system/doc/design_principles/sup_princ.xml +++ b/system/doc/design_principles/sup_princ.xml @@ -4,7 +4,7 @@ <chapter> <header> <copyright> - <year>1997</year><year>2011</year> + <year>1997</year><year>2012</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -136,7 +136,7 @@ init(...) -> M = F = atom() A = [term()] Restart = permanent | transient | temporary - Shutdown = brutal_kill | integer() >=0 | infinity + Shutdown = brutal_kill | integer()>0 | infinity Type = worker | supervisor Modules = [Module] | dynamic Module = atom()]]></code> @@ -160,10 +160,13 @@ init(...) -> be restarted.</p> <list type="bulleted"> <item>A <c>permanent</c> child process is always restarted.</item> - <item>A <c>temporary</c> child process is never restarted.</item> + <item>A <c>temporary</c> child process is never restarted + (not even when the supervisor's restart strategy + is <c>rest_for_one</c> or <c>one_for_all</c> and a sibling's + death causes the temporary process to be terminated).</item> <item>A <c>transient</c> child process is restarted only if it terminates abnormally, i.e. with another exit reason than - <c>normal</c>.</item> + <c>normal</c>, <c>shutdown</c> or <c>{shutdown,Term}</c>.</item> </list> </item> <item> @@ -181,8 +184,16 @@ init(...) -> terminated using <c>exit(Child, kill)</c>.</item> <item>If the child process is another supervisor, it should be set to <c>infinity</c> to give the subtree enough time to - shutdown.</item> + shutdown. It is also allowed to set it to <c>infinity</c>, if the + child process is a worker.</item> </list> + <warning> + <p>Be careful by setting the <c>Shutdown</c> strategy to + <c>infinity</c> when the child process is a worker. Because, in this + situation, the termination of the supervision tree depends on the + child process, it must be implemented in a safe way and its cleanup + procedure must always return.</p> + </warning> </item> <item> <p><c>Type</c> specifies if the child process is a supervisor or @@ -341,6 +352,10 @@ call:start_link(id1)</code> supervisor:terminate_child(Sup, Pid)</code> <p>where <c>Sup</c> is the pid, or name, of the supervisor and <c>Pid</c> is the pid of the child.</p> + <p>Because a <c>simple_one_for_one</c> supervisor could have many children, + it shuts them all down at same time. So, order in which they are stopped is + not defined. For the same reason, it could have an overhead with regards to + the <c>Shutdown</c> strategy.</p> </section> <section> |