Solution : https://service.sap.com/sap/support/notes/553476 (SAP Service marketplace login required)
Key words : 
running report /sapapo/sdorder_del efficiently, terms report /sapapo/sdorder_del, /sapapo/atp_all_sd_orders_del /sapapo/sdfield, scm advanced planning, sd request tables, apo/scm release, ms sql server, additional info/recommendation, /sapapo/cval_i reason, /sapapo/sdorder_inc_del
Related Notes : 
       
| 1425943 | /sapapo/sdorder_del: long runtime related to /sapapo/tbqtvb | 
| 1425698 | SDORDER_DEL 2nd tab: incorrct select. of sch. lines by date | 
| 1424032 | /sapapo/sdorder_del: No block size for deletion from LC | 
| 1419083 | SCM 4.1: Performance improvement sales order inbound | 
| 1378601 | /sapapo/sdorder_del: Sel. for deletion from liveCache and DB | 
| 1374938 | /SAPAPO/SDORDER_DEL del's too many /SAPAPO/CIFLOOKU entries | 
| 1370408 | not able to delete ATP CVC's | 
| 1367425 | /SAPAPO/SDORDER_DEL: Performance of deletion from liveCache | 
| 1325331 | Deletion of superfluous entries from table /sapapo/ordpart | 
| 1308958 | /SAPAPO/SDORDER_DEL: log error for table /SAPAPO/RIICHAIN | 
| 1286981 | /SAPAPO/SDORDER_DEL: shortdump DBIF_RSQL_INVALID_RSQL | 
| 1286029 | Product cannot be deleted | 
| 1286026 | Performance during SELECT from table /sapapo/ord_link (II) | 
| 1263954 | /SAPAPO/SDORDER_DEL: selective deletion & WUF | 
| 1261739 | /SAPAPO/ZRD_SDORDER_DEL: Deletion performance in ciflooku | 
| 1260980 | /SAPAPO/SDORDER_DEL: selective deletion & WUF | 
| 1248096 | /sapapo/sdorder_del: Long runtime when deleting orders | 
| 1247395 | /sapapo/sdorder_del: Long runtime when deleting orders | 
| 1157669 | /SAPAPO/SDRQCR21: missing obref inconsistency | 
| 1156965 | /SAPAPO/SDRQCR21: missing obref inconsistency | 
| 1152103 | /SAPAPO/SDORDER_DEL: Deleting with order number (OLTP) | 
| 1150281 | /SAPAPO/SDRQCR21: missing obref inconsistency | 
| 1097921 | Entries in /SAPAPO/POSMAPN with initial values | 
| 1086364 | /sapapo/sdorder_del: Performance /sapapo/ciflooku | 
| 1070697 | Error /SAPAPO/ATP 113 during /SAPAPO/SDORDER_DEL | 
| 1061860 | /sapapo/sdorder_del: performance deletion /sapapo/ciflooku | 
| 1050822 | /sapapo/ordadm_i and /sapapo/schedlin records are missing | 
| 1037363 | /SAPAPO/SDORDER_DEL del's too many /SAPAPO/CIFLOOKU entries | 
| 1036808 | /sapapo/sdorder_del: MM tables are ignored | 
| 1032188 | /sapapo/sdorder_del: tbhead, tbparam and tbqtvb enhancement | 
| 1010993 | /sapapo/sdorder_del: /sapapo/ciflooku table not checked | 
| 1008133 | Runtime for report /SAPAPO/SDORDER_DEL is too long | 
| 1006928 | Error DBIF_RSQL_SQL_ERROR with /SAPAPO/SDORDER_DEL | 
| 991354 | Untitled frame in report /SAPAPO/SDORDER_DEL | 
| 977743 | Report /SAPAPO/SDORDER_MIGRATE fails with dump | 
| 966989 | /sapapo/sdorder_del: Test flag and log for deleted items | 
| 965204 | /SAPAPO/SDORDER_DEL does not delete /SAPAPO/MM_SCHED entries | 
| 958652 | /SAPAPO/SDORDER_DEL terminates with GETWA_NOT_ASSIGNED | 
| 954555 | Report /sapapo/sdorder_del selects incorrect orders | 
| 951517 | Spurious information message in report /sapapo/sdorder_del | 
| 944758 | /SAPAPO/SDORDER_DEL: ATPPARAM not deleted | 
| 931502 | Performance of /SAPAPO/DELETE_PRODUCTS | 
| 922003 | /sapapo/sdorder_del: memory consumption | 
| 920417 | SDORDER_DEL in background job: the period is not considered | 
| 904462 | Error SYSTEM_NO_ROLL in /SAPAPO/SDORDER_DEL | 
| 900730 | /SAPAPO/ATP_ALL_SD_ORDERS_DEL deletes across clients | 
| 894294 | /sapapo/sdorder_del: Performance and advice (as of SCM 4.0) | 
| 878645 | Allocation pb with report /SAPAPO/SDORDER_DEL in background | 
| 866031 | /sapapo/sdorder_del: improve memory consumption | 
| 848274 | Allocation pb with report /SAPAPO/SDORDER_DEL in background | 
| 846891 | Problem with the allocation check in /SAPAPO/SDORDER_DEL | 
| 825298 | /sapapo/sdorder_del: Deletion by Order Number (OLTP) | 
| 803012 | Error TSV_TNEW_BLOCKS_NO_ROLL_MEMORY in /sapapo/sdorder_del | 
| 802310 | Unable to delete orders from an inactive planning version | 
| 797129 | /sapapo/sdorder_del: no deletion of inconsistent orders | 
| 788458 | SDORDER_DEL: Logging of the deletion process | 
| 784539 | RLCDELETE/SDORDER_DEL: missing functions | 
| 781017 | /sapapo/sdorder_del: obsolete entries in /sapapo/obref | 
| 761238 | /sapapo/sdorder_del: test flag for data deletion on the DB | 
| 748976 | Problem with the allocation check in /SAPAPO/SDORDER_DEL | 
| 736275 | Program SDORDER_DEL does not delete allocation assignments | 
| 719809 | Unable to delete sales order from inactive planning version | 
| 705901 | /SAPAPO/SDORDER_DEL: New selection screen as of SCM 4.0 | 
| 703280 | Customer requirements cannot be deleted in the liveCache | 
| 674204 | /SAPAPO/SDORDER_DEL terminates: DBIF_RSQL_SQL_ERROR | 
| 657214 | /sapapo/sdorder_del: Documentation and usability | 
| 624539 | /sapapo/sdorder_del: Extended check for allocation | 
| 619414 | Deletion report /SAPAPO/SDORDER_DEL terminates | 
| 619228 | /sapapo/sdorder_del: accesibility and performance issues | 
| 617922 | /sapapo/sdorder_del: Field catalog is deleted completely | 
| 609843 | Obsolete /SAPAPO/POSMAPN entries remain in the APO | 
| 596019 | /SAPAPO/SDORDER_DEL deletes field catalog for sched. agrmnts | 
| 594835 | Performance of the deletion report /SAPAPO/SDORDER_DEL | 
| 590463 | Error in the /SAPAPO/SDORDER_DEL: Eliminate inconsistencies | 
| 584795 | /sapapo/sdorder_del: /sapapo/posmapn for deliveries | 
| 575908 | /SAPAPO/SDORDER_DEL: Text symbols and selection texts | 
| 558636 | Deletion of deliveries from the mapping table not possible | 
| 558513 | Inconsistent data in ATP tables | 
| 555091 | Performance of SD data reorganization | 
| 552922 | /SAPAPO/SDFIELD Table is too big | 
| 549812 | Performance: Selection in /SAPAPO/SDORDER_DEL | 
| 546459 | /sapapo/sdorder_del: Performance and recommendations | 
| 543796 | Deleting all orders in SDORDER_DEL is not possible | 
| 542184 | Inconsistent SD data in APO cannot be deleted | 
| 541045 | Report /SAPAPO/SDORDER_DEL terminates | 
| 535278 | No translation of program document./sapapo/sdorder_del | 
| 534002 | Performance: Deletion of the SD database tables in APO | 
| 528070 | It takes too long to delete SD database tables in APO | 
| 522317 | Where-used list: Location | 
| 520703 | Product cannot be deleted | 
| 513869 | Performance improvement: TP/VS and BOP | 
| 510912 | BOP: Tips & Tricks | 
| 508364 | Documentation and interface change for /SAPAPO/SDORDER_DEL | 
| 504620 | Deletion of R/3 data that are no longer required in APO | 
| 501446 | List of all composite and FAQ notes about APO ATP | 
| 491449 | Deleting large datasets in APO database tables | 
| 490685 | Backorder processing: performance update | 
| 488077 | Not possible to delete the R/3 data in the APO database | 
| 444641 | Correction of incorrect sales order requirements with APO | 
| 420606 | Collective SAP Note for GATP performance in APO 3.0A | 
| 420598 | Composite SAP Note for GATP performance in APO 3.1 | 
| 329302 | Delete function for supplied orders is missing |