Solution : https://service.sap.com/sap/support/notes/161298 (SAP Service marketplace login required)
Key words : 
0co_om_wbs_4 additional key words bw, symptom loading transaction data, sap bw takes, bw-bct-coom, overhead cost projects, extraction job remains, performing database accesses, source system implement, solution implement, source system
Related Notes : 
       
| 194994 | BW extractors:Performance informtn sources projects | 
| 175605 | Transaction KB6*: Missing line items | 
| 156319 | Collective note performance BW 1.2B | 
| 155197 | BW Extractors CO OM: long/endless runtimes | 
| 97413 | Cost element report: DUMP or long runtime Version 2 |