[Koha-devel] RFC: Koha::Persistent - for plack and general performance

[Paul Poulain]

Le 06/04/2012 12:40, Chris Cormack a écrit :
>> Am I right if I say that the 1st technique is the best and is what is
>> achieved by ->flush_cache() method of (memoize::)memcached ?
> 
> The third option, and best option imho is when a value is change, it
> is injected into the cache at that point.
Agreed, I have missed this option !

> The second best option is to
> remove the object from the cache (option 1) Frederic is right, the big
> when is in caching serialised objects, not sql results, things like
> the rdbms and DBD::Gofer cache sql results well.
I think I don't understand what you mean here.

> Could be, but like I was saying we shouldn't be using memcached (or
> application level caching) for simple sql queries, we should be
> caching the things that either are slow queries or are the result of a
> lot of queries. We should be caching processed results, things that
> are computational expensive to generate. Also redis seems to be the
> clear leader in key-value stores now, we should definitely investigate
> that more.
So how should we do to reduce the load caused by the repeated SQL
queries for systempreferences, languages, itemtypes, patron categories,... ?

You think we should use something that is not caching ?
You suggest memcache caching for complex things and another method for
"simple" queries ? which method ?

Could it be an option to build dynamically a perl file that contains,
for example, a hash with all sysprefs, that is loaded through a
use Koha::Cache::Sysprefs;
Koha::Cache::Sysprefs.pm being
my $syspref = { 'IndependantBranche' => 0, 'LibraryName'=> "my library",
...}
that is just build automatically, and only once ?

Aren't the sysprefs and some other parameters stable enough to accept
flushing Plack threads when something is changed ?

(I'm not sure at all this idea is good, just want to avoid missing
something interesting )

-- 
Paul POULAIN
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