Performance: WorkflowLinkedObject - checks on linked copies really takes a lot of time + cache looks like not working

This is the result of my LinkedWorkflow cache after 32 run of 5'000 pages with 6'000 users LDAP (parsing 25 pages each of them).

WorkflowLinkedObject : Linked workflow object cache
1758 entries
Successful cache hits : 7134 / 335588 total, Efficiency : 2.13 % Number of groups : 9998

Moreover with YourKit it looks like such LinkedObjects checks are taking a lot of time (first cause of performance).

This is quite stupid as I do not have one single linked copy on all my 30'000 pages site! So perhaps we could rapidly develop something in order to:

• launch a query at Jahia startup in order to know if there is some linked copies on the current site. If this is not the case then avoid making such a request (then do not forget to turn off this variable is an author suddently make a linked copy)
• Make a variable in the jahia.properties files in order to restrict the use of linked copies. Most of our customers are not using linked copies so they do not need such a menu in the engine. Such a check couls also perfectly be done in the license key too (but we need to generate custom license key so this is more complex). Here again what about a site with linked copies and if the siteadmin turns this setting to false in the jahia.properties afterwards. What is the result on existing linked copies? But here again we could bypasse such a "default value" on Jahia startup if we discover (through a simple SQL queries) that there was some old existing linked copies in order to reactivate such checks...

Finally of course we need to make such a cache works...