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2016-11-15Expand on the behavior of supervisorsBrujo Benavides
Add additional details on the behavior of supervisors when reaching maximum restart intensity, as stated by @rvirding at [Medium](https://goo.gl/XhwpSL)
2016-06-13Update STDLIB documentationBjörn Gustavsson
Language cleaned up by the technical writers xsipewe and tmanevik from Combitech. Proofreading and corrections by Björn Gustavsson and Hans Bolinder.
2016-04-25Merge branch 'raimo/new-gen-state-machine/OTP-13065'Raimo Niskanen
* raimo/new-gen-state-machine/OTP-13065: (52 commits) Add section on state filtering Promote gen_statem over gen_fsm Modify code_change/4 to return CallbackMode Use ?NAME macro in examples Introduce Fred Herbert suggested additions Introduce corrections from Fred Hebert and Ingela Use .png pictures instead of .gif Write Design Principles chapter Fix missing short forms for event timeout Do more intricate Fred Hebert doc changes Change Caller -> From as suggested by Fred Hebert Do documentation improvements from Fred Hebert Fix broken documenation reference Rename state_timeout -> event_timeout Fix most of the system docs and emacs mode Change code_change/4 to {ok,State,Data} Fixup sharpened test suite Sharpen test suite Remove the remove_event action and all alike Relax caller() type check and cleanup ... Conflicts: lib/stdlib/src/gen.erl lib/stdlib/src/gen_event.erl lib/stdlib/src/gen_fsm.erl lib/stdlib/src/gen_server.erl lib/stdlib/test/error_logger_forwarder.erl
2016-03-15update copyright-yearHenrik Nord
2016-03-03Fix most of the system docs and emacs modeRaimo Niskanen
2016-02-03Speed up supervisor:count_children/1; simple_one_for_oneRory Byrne
Speed up supervisor:count_children/1 for simple_one_for_one supervisors. This is achieved by avoiding looping through all the child process and verifying that each one is alive. For a supervisor with 100,000 'temporary' children the count-time will drop from approx 25ms to about 0.005ms. For a supervisor with 100,000 'permanent' or 'transient' children the count-time will drop from approx 30ms to about 0.005ms. This avoids having the supervisor block for an extended period while the count takes place. Under normal circumstances the accuracy of the result should also improve since the duration is too short for many processes to die during the count.
2015-11-04[stdlib] Correct documentationHans Bolinder
Fix mistakes found by 'xmllint'.
2015-06-18Change license text to APLv2Bruce Yinhe
2015-05-26Don't store child that returns ignore in simple supervisorJames Fish
If a child of a simple_one_for_one returns ignore from its start function no longer store the child for any restart type. It is not possible to restart or delete the child because the supervisor is a simple_one_for_one. Previously a simple_one_for_one would crash, potentially without shutting down all of its children, when it tried to shutdown a child with undefined pid. Previous only one undefined pid child was stored in a simple_one_for_one supervisor no matter how many times the child start function returned ignore.
2014-11-06Add documentation of maps in supervisor flags and child specsSiri Hansen
2014-03-05stdlib: Improve the doc of the supervisor's via referenceHans Bolinder
Most of the updates have already been made in 'Fix alternative registry type annotations in supervisor', a5412706f4185fddbac29216a49affd1e9f11da0. Thanks to MaximMinin.
2013-07-11Merge branch 'maint'Fredrik Gustafsson
2013-07-11Fix supervisor typogoofansu
`I` should be `If`
2013-06-12Update copyright yearsBjörn-Egil Dahlberg
2013-04-19Convert XML files to UTF-8Hans Bolinder
2013-03-08Delete obsolete note about simple-one-for-one supervisorMagnus Henoch
Since commit 47759479146ca11ad81eca0bb3236b265e20601d, simple-one-for-one supervisors _do_ kill their children explicitly on shutdown. That commit also removed this note, but it seems like the merge commit 45b4d5309e0686cc5fa28506de76f75b598bbd95 incorrectly reinstated it.
2012-10-11Fix documentation about how supervisor handles crash in child's start functionSiri Hansen
2012-10-05Have supervisor send errors up the chainTomas Pihl
If a child fails to start, supervisor relies upon error_logger which does not work when IO is inhibited. Instead pass the error up the chain and let someone else use a proper Reason for any possible printouts.
2012-03-30Update copyright yearsBjörn-Egil Dahlberg
2012-03-16Merge branch 'rj/fix-supervisor-shutdown-doc' into maintGustav Simonsson
* rj/fix-supervisor-shutdown-doc: Fix small typo in kernel app doc Cosmetic: split very long lines from supervisor doc Fix supervisor doc: Shutdown, MaxR and MaxT type specs Add the type restrictions in the code comments Remove trailing spaces OTP-9987
2012-03-05Leave control back to gen_server during supervisor's restart loopSiri Hansen
When an attempt to restart a child failed, supervisor would earlier keep the execution flow and try to restart the child over and over again until it either succeeded or the restart frequency limit was reached. If none of these happened, supervisor would hang forever in this loop. This commit adds a timer of 0 ms where the control is left back to the gen_server which implements the supervisor. This way any incoming request to the supervisor will be handled - which could help breaking the infinite loop - e.g. shutdown request for the supervisor or for the problematic child. This introduces some incompatibilities in stdlib due to new return values from supervisor: * restart_child/2 can now return {error,restarting} * delete_child/2 can now return {error,restarting} * which_children/1 returns a list of {Id,Child,Type,Mods}, where Child, in addition to the old pid() or 'undefined', now also can be 'restarting'.
2012-02-24Cosmetic: split very long lines from supervisor docRicardo Catalinas Jiménez
2012-02-24Merge branch 'uw/extending_gen' into maintGustav Simonsson
* uw/extending_gen: Add plugin support for alternative name lookup OTP-9945
2012-02-24Fix supervisor doc: Shutdown, MaxR and MaxT type specsRicardo Catalinas Jiménez
The next code snippets from supervisor.erl show that Shutdown from a child specification must be greater than zero and the same applies to MaxT. --- supervisor.erl ---------------------------------------------------------- validShutdown(Shutdown, _) when is_integer(Shutdown), Shutdown > 0 -> true; validShutdown(infinity, _) -> true; validShutdown(brutal_kill, _) -> true; validShutdown(Shutdown, _) -> throw({invalid_shutdown, Shutdown}). validIntensity(Max) when is_integer(Max), Max >= 0 -> true; validIntensity(What) -> throw({invalid_intensity, What}). validPeriod(Period) when is_integer(Period), Period > 0 -> true; validPeriod(What) -> throw({invalid_period, What}). -----------------------------------------------------------------------------
2011-12-20Don't save child spec for temporary child if child's start func returns ignoreSiri Hansen
Supervisor should never keep child specs for dead temporary children.
2011-11-24Add plugin support for alternative name lookupUlf Wiger
OTP behaviour instances (gen_server, gen_fsm, gen_event) can currently register themselves either locally or globally, and the behaviour libraries (including gen.erl) support both addressing methods, as well as the normal Pid and {Name, Node}. However, there are alternative registry implementations - e.g. gproc - and one can well imagine other ways of locating a behaviour instance, e.g. on a node connected only via a TCP tunnel, rather than via Distributed Erlang. In all these cases, one needs to write extra code to identify the behaviour instance, even though the instance itself need not be aware of how it is located. This patch introduces a new way of locating a behaviour instance: {via, Module, Name}. Module is expected to export a subset of the functions in global.erl, namely: register_name(Name, Pid) -> yes | no whereis_name(Name) -> pid() | undefined unregister_name(Name) -> ok send(Name, Msg) -> Pid Semantics are expected to be the same as for global.erl This can be used in all places where {global, Name} is accepted. faulty export in gen_fsm_SUITE.erl await process death in dummy_via:reset() fix error in gen_[server|fsm]:enter_loop() fix documentation
2011-11-16Improve documentation on supervisor restart strategySiri Hansen
2011-10-20Merge branch 'cf/simple_one_for_one_shutdown'Henrik Nord
* cf/simple_one_for_one_shutdown: Explain how dynamic child processes are stopped Stack errors when dynamic children are stopped Explicitly kill dynamic children in supervisors Conflicts: lib/stdlib/doc/src/supervisor.xml OTP-9647
2011-10-10Add a warning to docs about workers' shutdown strategyChristopher Faulet
2011-10-10Allow an infinite timeout to shutdown worker processesChristopher Faulet
Now, in child specification, the shutdown value can also be set to infinity for worker children. This restriction was removed because this is not always possible to predict the shutdown time for a worker. This is highly application-dependent.
2011-09-26Correct XML filesHans Bolinder
2011-09-16Explain how dynamic child processes are stoppedChristopher Faulet
2011-09-16Explicitly kill dynamic children in supervisorsChristopher Faulet
According to the supervisor's documentation: "Important note on simple-one-for-one supervisors: The dynamically created child processes of a simple-one-for-one supervisor are not explicitly killed, regardless of shutdown strategy, but are expected to terminate when the supervisor does (that is, when an exit signal from the parent process is received)." All is fine as long as we stop simple_one_for_one supervisor manually. Dynamic children catch the exit signal from the supervisor and leave. But, if this happens when we stop an application, after the top supervisor has stopped, the application master kills all remaining processes associated to this application. So, dynamic children that trap exit signals can be killed during their cleanup (here we mean inside terminate/2). This is unpredictable and highly time-dependent. In this commit, supervisor module is patched to explicitly terminate dynamic children accordingly to the shutdown strategy. NOTE: Order in which dynamic children are stopped is not defined. In fact, this is "almost" done at the same time.
2011-08-23fix supervisors restarting temporary childrenFred Hebert
In the current implementation of supervisors, temporary children should never be restarted. However, when a temporary child is restarted as part of a one_for_all or rest_for_one strategy where the failing process is not the temporary child, the supervisor still tries to restart it. Because the supervisor doesn't keep some of the MFA information of temporary children, this causes the supervisor to hit its restart limit and crash. This patch fixes the behaviour by inserting a clause in terminate_children/2-3 (private function) that will omit temporary children when building a list of killed processes, to avoid having the supervisor trying to restart them again. Only supervisors in need of restarting children used the list, so the change should be of no impact for the functions that called terminate_children/2-3 only to kill all children. The documentation has been modified to make this behaviour more explicit.
2011-05-12rHans Bolinder
Use Erlang specs and types for documentation
2011-04-12Allow supervisor:terminate_child(SupRef,Pid) for simple_one_for_oneSiri Hansen
supervisor:terminate_child/2 was not allowed if the supervisor used restart strategy simple_one_for_one. This is now changed so that children of this type of supervisors can be terminated by specifying the child's Pid.
2010-09-17Clarify documentation of shutdown timeout in supervisor child specsMagnus Henoch
Make it explicit that the shutdown timeout is to be specified in milliseconds.
2010-02-12Merge branch 'jn/supervisor_child_count_only' into ccase/r13b04_devErlang/OTP
* jn/supervisor_child_count_only: Add count_children/1 to supervisor.erl to determine the number of OTP-8436 Added supervisor:count_children/1 to count the number of children being managed without the memory impact of which_children/1. (Thanks to Jay Nelson.)
2010-02-10Add count_children/1 to supervisor.erl to determine the number ofJay Nelson
children being managed without the memory impact of which_children/1 The function which_children/1 returns a list of the child processes currently being supervised, but it has the penalty of creating a new list thereby consuming more memory. In low memory situations it is often desirable to know which supervisor may have generated many processes, but the act of discovering the culprit should not cause the node to crash (or worse a different node if the kernel kills one randomly). The new function count_children/1 can give an indication of which supervisor is taxing resources the most without adding to the burden. Rather than creating a new list, it walks the supervisor's internal children structure using an accumulator function so that any used memory can be incrementally collected yet the resulting count can still be obtained. The return result of count_children/1 is a property list of counts containing: - {specs, Total_Num_Child_Specs} - {active, Num_Active_Child_Processes_Of_Supervisor_Or_Worker_Type} - {supervisors, Num_Supervisor_Type_Children_Including_Dead_Processes} - {workers, Num_Worker_Type_Children_Including_Dead_Processes} This patch was made in response to mailing list discussions of the problem diagnosing heavily taxed production systems. I cannot find the original request, but http://www.erlang.org/cgi-bin/ezmlm-cgi/4/35060 is my original post of the patch.
2009-11-20The R13B03 release.OTP_R13B03Erlang/OTP