Bug #90823 for FCGI-ProcManager-MaxRequests: Add an option to vary PM_MAX_REQUESTS value

Hello, I've made a patch to add an option to vary PM_MAX_REQUESTS value between workers. Under some conditions, where PM_MAX_REQUESTS and each request is relatively small, all workers reach the limit and exit suddenly. To prevent this issue PM_MAX_REQUESTS_VAR environment variable is added. See the attached patch. Please let me know if it needs any changes. Thanks.

From 51ecd9be66f3224cb0ea17cd6ed2481d35ec7407 Mon Sep 17 00:00:00 2001 From: Haruka Iwao <haruka@fout.jp> Date: Thu, 14 Nov 2013 14:36:27 +0900 Subject: [PATCH 1/2] MaxRequests.pm: Add PM_MAX_REQUESTS_VAR variable to randomize counter When set, PM_MAX_REQUESTS + random[0..PM_MAX_REQUESTS_VAR) is set to request_counter to prevent all processeS to shut down at once. --- lib/FCGI/ProcManager/MaxRequests.pm | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/lib/FCGI/ProcManager/MaxRequests.pm b/lib/FCGI/ProcManager/MaxRequests.pm index 84644e1..f89367c 100644 --- a/lib/FCGI/ProcManager/MaxRequests.pm +++ b/lib/FCGI/ProcManager/MaxRequests.pm @@ -9,6 +9,7 @@ sub new { my $proto = shift; my $self = $proto->SUPER::new(@_); $self->{max_requests} = $ENV{PM_MAX_REQUESTS} || 0 unless defined $self->{max_requests}; + $self->{max_requests_var} = $ENV{PM_MAX_REQUESTS_VAR} || 0 unless defined $self->{max_requests_var}; return $self; } @@ -18,6 +19,10 @@ sub handling_init { my $self = shift; $self->SUPER::handling_init(); $self->{_request_counter} = $self->max_requests; + if($self->{max_requests_var}) { + $self->{_request_counter} += (time ^ ($$ + ($$ << 15))) % $self->{max_requests_var}; + } + $self->pm_info("Max request counter set to $self->{_request_counter}."); } sub pm_post_dispatch { -- 1.7.1 From a6bfadc486dd800bad66d481c5a67dde126f6cad Mon Sep 17 00:00:00 2001 From: Haruka Iwao <haruka@fout.jp> Date: Fri, 22 Nov 2013 18:34:14 +0900 Subject: [PATCH 2/2] MaxRequests.pm: Add a note about PM_MAX_REQUESTS_VAR --- lib/FCGI/ProcManager/MaxRequests.pm | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/lib/FCGI/ProcManager/MaxRequests.pm b/lib/FCGI/ProcManager/MaxRequests.pm index f89367c..5d4e22d 100644 --- a/lib/FCGI/ProcManager/MaxRequests.pm +++ b/lib/FCGI/ProcManager/MaxRequests.pm @@ -67,6 +67,11 @@ number of requests, it simple exit, and manager starts another server process. Maximum number of requests can be set from PM_MAX_REQUESTS environment variable, max_requests - constructor argument and max_requests accessor. +When PM_MAX_REQUESTS is relatively small and processing times of requests varies little, +all of worker processes reach the limit and exit suddenly. To prevent this issue, +you can use PM_MAX_REQUESTS_VAR environment variable so that each worker randomly +chooses a value between [PM_MAX_REQUESTS, PM_MAX_REQUESTS + PM_MAX_REQUESTS_VAR). + =head1 OVERLOADED METHODS =head2 new