SAP Message VK459 - Validity period &1-&2 for planning could be too long

Diagnosis
You want to carry out planning for a condition record that is validfrom &v1& to &v2&.
Planning is probably impractical for such a long validity period.

System Response
Since a long validity period can mean that too many item lines arecreated in CO-PA, this can lead to problems with performance or memoryspace.

Procedure
Check whether planning is really necessary for this validity period.