Solution : https://service.sap.com/sap/support/notes/1279352 (SAP Service marketplace login required)
Key words :
import sleep time improves mdm performance, import manager user guides, import sleep time ends, import sleep time, time mds devotes, mds continues alternating, safeand timely import, large import job, entire import job, import slices divide
Related Notes :
| 1376342 | Repository access during mass import |