[FELIX-5467] MultiPropertyFilterIndex is unusable when a service reference contains a lot of values for one key

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: org.apache.felix.dependencymanager-r8
• Fix Version/s: org.apache.felix.dependencymanager-r9
• Component/s: Dependency Manager
• Assignee: Pierre De Rop
• Reporter: Jeroen Daanen
• Created: 27/Dec/16 13:39
• Updated: 29/Dec/16 08:26
• Resolved: 27/Dec/16 23:23

Description

Upon addition of a service, the MultiPropertyFilterIndex creates a set of keys using the keys and values of the service reference properties. If the value is an array of values it creates keys for each possible permutation of those values so that the service reference can be retrieved if in the service dependency filter multiple values are specified (e.g. (&(objectClass=SomeClass)(&(a=x)(a=n)(a=y)(b=y)(c=z)))). If there are a lot of values for a key this results in a huge memory consumption, making it impossible to use.
Now, in my application I always specify just one value in the service filter (e.g. there is a service which has multiple values for property "a" but I only specify one: (&(objectClass=SomeClass)(&(a=x)(b=y)(c=z)))) so I don't need those permutations, but because my property has a lot of values (>10) I cannot use the MultiPropertyFilterIndex causing a significant performance loss.

I would like to suggest to add the possibility to leave out creating the permutation of values for a service property if you specify so in your filter properties. For instance by preceding the property configuration with '#', e.g. -Dorg.apache.felix.dependencymanager.filterindex=*aspect*;*adapter*;objectClass;objectClass,#a,b,c