At the moment we cache numerous pieces of information in module-level
variables which then do not get updated in other threads/processes when
they are changed by the user. This is a serious usability issue.
Examples of this include the way we treat sysprefs (there is now a
method to disable the syspref cache, but by default it is enabled),
notices, frameworks, field mappings, and koha-conf.xml, at least.
This patch sets the stage for eliminating this problem by making it
possible to convert module-level cache variables into variables that
are actually backed by whatever caching system may be configured. This
is done through a special Koha::Cache::Object class which can be tied
to the variables that are being used for caching and provided with a
constructor method/closure to allow the cache to be reloaded when it
expires. For example:
my $cache = Koha::Cache->new();
my $data = 'whatever';
my $variable = Koha::Cache->create_scalar(
{
'key' => 'whatever',
'timeout' => 2,
'constructor' => sub { return $data; },
}
);
print "$$variable\n"; # Prints "whatever"
The one change this necessitates for accessing the data is that the
variable must be dereferenced an additional time before use (i.e.
$$variable instead of $variable). There is no difference when the
variable tied is a hash (created with Koha::Cache->create_hash). This
is a small price to pay for Koha working in a multi-threaded, persistent
environment. This change will also make caching easier in general.
CHI was incompatible with the variable tying, so this patch also removes
the dependency on CHI, using instead Cache::Memcached::Fast,
Cache::FastMmap, and Cache::Memory, when they are available.
To test:
1) Apply patch.
2) Run unit test t/Cache.t (after setting the MEMCACHED_SERVERS and
CACHING_SYSTEM environment variables). As no changes were made to
the tests already in that file, this passing demonstrates there
are no regressions.
3) With memcached caching enabled (you must set the MEMCACHED_SERVERS
and CACHING_SYSTEM environment variables) and DEBUG turned on (i.e.
the DEBUG environment variable set to 1), try running a report via
the web service ([intranet]/cgi-bin/koha/svc/report?id=1 and check
your web server logs to confirm that there are messages like
"get_from_cache for intranet:report:id:1" in them.
4) If the reports worked, sign off.
NOTE: Technically you could test this without needing memcached by
installing libcache-fastmmap-perl and setting CACHING_SYSTEM to
'fastmmap' instead of 'memcached'. You could also install libcache-perl
and set CACHING_SYSTEM to 'memory' but there would be little point as
the cached variables would go out of scope in between runs.
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
This reverts commit 215abc8024.
The 3 patches for bug 8089 have been reverted, because they break
jenkins & Koha.
A follow-up has been provided, but it does not solve the problem on my
test server, it just changes the error message.
After a discussion with jared, Dobrica should work on another patch, so
the best option is to revert.
1. Replace all instances of memoize_memcached with appropriate calls
into Koha::Cache:
* reports/guided_reports.pl
* C4::Biblio::GetMarcStructure
* C4::Languages::getFrameworkLanguages
* C4::Languages::getAllLanguages
* C4::SQLHelper::GetPrimaryKeys
* C4::SQLHelper::_get_columns
2. Replace all references to memcached with the appropriate calls into
Koha::Cache in C4::Context.
Test plan :
* have DEBUG env set to 1
* reach addbiblio page to test the patch in Biblio.pm, or setup more than 1
language
* you should see in the logs that you're reading and writing from cache
* run the test suite twice both with and without the following environment
variables set:
export MEMCACHED_SERVERS=127.0.0.1:11211
export MEMCACHED_NAMESPACE=KOHA
export CACHING_SYSTEM=memcached
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
I'm unsure about some of the caching times 10000 is a long long time,
but other than that, works fine.
Implements cache handlers for Memcached, mmap shared-file persistent,
and in-process memory caches. If CHI is unavailable, Koha::Cache::Memcached
will fall back to using Cache::Memcached::Fast, or caching will be skipped
without croaking.
To test: run t/Cache.t with the following options, before and after
installing CHI:
2. Tests 3-9 should be skipped with the following:
export CACHING_SYSTEM=
2. You should receive two failures with the following if CHI is not installed:
export CACHING_SYSTEM=memory
3. You should receive two failures with the following if CHI is not installed:
export CACHING_SYSTEM=fastmmap
4. You will need memcached activated for the following to work (but it
will work both with and without CHI):
export CACHING_SYSTEM=memcached
export MEMCACHED_SERVERS=127.0.0.1:11211
export MEMCACHED_NAMESPACE=KOHA
5. You should receive two failures with the following:
export CACHING_SYSTEM=thisdoesntexist
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Works as advertised, now we need a follow up to add the new dependency.
http://bugs.koha-community.org/show_bug.cgi?id=8029
Unit test for Koha/Cache.pm (which includes Koha/Cache/Memcached.pm)
Note that in order to test Koha::Cache you must export the environment variable
MEMCACHED_SERVERS. For example:
$ export MEMCACHED_SERVERS=127.0.0.1:11211
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
