More than 5 million entries in KMC_RIDID_SETS

Hi,

i have a problem in our production database of our Netweaver 7.30 Portal.
We have many automated processes, which use KMC. The time of the processes increased because the KMC operations do a full table scan on the table KMC_RIDID_SETS.

In our test system in this table are no entries, in our production environment, there are over 5 million entries. Whats really strange is, that the "SET_IDs" have no corresponding "NODE_ID". The value of the node id is always "-1", so in my opinion this is not a valid reference.

Could anyone tell me if it is secure to delete the entries with SQL, which point to the node_ide "-1"?

Many thanks

Regards

Alex