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Bug 13193: Make Memcached usage fork safe

When a high enough number of forks try to access for example system
preferences with Koha::Cache using memcached as backend the results of
different cache requests get mixed up.

The problem is fixed by using Cache::Memcached::Fast::Safe that is a
fork safe version of Cache::Memcached::Fast.

Sponsored-by: The National Library of Finland
Signed-off-by: David Cook <dcook@prosentient.com.au>

Works as described, and solves an insidious difficult to debug
problem in Koha.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
20.05.x
Joonas Kylmälä 3 years ago
committed by Martin Renvoize
parent
commit
31f1a76625
Signed by: martin.renvoize GPG Key ID: 422B469130441A0F
  1. 7
      C4/Installer/PerlDependencies.pm
  2. 6
      Koha/Cache.pm
  3. 2
      koha-tmpl/intranet-tmpl/prog/en/modules/about.tt

7
C4/Installer/PerlDependencies.pm

@ -265,7 +265,12 @@ our $PERL_DEPS = {
'Cache::Memcached::Fast' => {
'usage' => 'Caching',
'required' => '0',
'min_ver' => '0.17'
'min_ver' => '0.19'
},
'Cache::Memcached::Fast::Safe' => {
'usage' => 'Caching',
'required' => '0',
'min_ver' => '0.06'
},
'Cache::FastMmap' => {
'usage' => 'Caching',

6
Koha/Cache.pm

@ -87,7 +87,7 @@ sub new {
$self->{namespace} .= ":$subnamespace:";
if ( $self->{'default_type'} eq 'memcached'
&& can_load( modules => { 'Cache::Memcached::Fast' => undef } )
&& can_load( modules => { 'Cache::Memcached::Fast::Safe' => undef } )
&& _initialize_memcached($self, @servers)
&& defined( $self->{'memcached_cache'} ) )
{
@ -120,9 +120,9 @@ sub _initialize_memcached {
. join( ', ', @servers )
. " with "
. $self->{'namespace'};
# Cache::Memcached::Fast doesn't allow a default expire time to be set
# Cache::Memcached::Fast::Safe doesn't allow a default expire time to be set
# so we force it on setting.
my $memcached = Cache::Memcached::Fast->new(
my $memcached = Cache::Memcached::Fast::Safe->new(
{
servers => \@servers,
compress_threshold => 10_000,

2
koha-tmpl/intranet-tmpl/prog/en/modules/about.tt

@ -102,7 +102,7 @@
[% CASE # nowhere %]
<span class="status_warn">Nowhere</span> Note that the right place to define the memcached config is in your $KOHA_CONF file. Currently you do not have a valid memcached configuration defined.
[% END %]
[% IF effective_caching_method != 'Cache::Memcached::Fast' %]
[% IF effective_caching_method != 'Cache::Memcached::Fast::Safe' %]
| Effective caching method: [% effective_caching_method | html %]
[% END %]
</td>

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