Solution : https://service.sap.com/sap/support/notes/505608 (SAP Service marketplace login required)
Summary : 
      SAP Note details reorganization solutions for the ballooning size of IDOCREL and SRRELROLES database tables within the IDoc and ALE environments. As applications store links between business objects in these tables for monitoring and audit purposes, their exponential growth can occur. The report RSRLDREL is recommended for reorganizing or deleting these links, especially types IDC8 and IDCA after successful IDoc processing in target systems. Care must be taken with types IDC0, IDC1, IDC4, and IDCB to avoid losing information critical for document tracing. Options for selective deletion based on object types and roles are available, enhancing flexibility and system performance. Related SAP Notes provide further modifications and improvements.
Key words : 
usage idc0              outbeleg    outidoc    document trace idc1              inidoc      inbeleg    document trace idcb              inidoc      outbeleg    document trace idc4              inidoc      outidoc    ale audit idc9              outidoc    inbeleg     ale audit idc8              inidoc      intid      monitoring idca              outidoc    outid       monitoring, ale audit idc4, document trace idc0 links, monitoring idc8 links, subsequent document trace, roles inidoc, document trace, idoc monitoring, idc1 links, role inbeleg
Related Notes : 
       
| 1385766 | RSRLDREL2: Improved performance | 
| 707820 | Performance: Object links and RSRLDREL | 
| 706478 | Preventing Basis tables from increasing considerably | 
| 574349 | IDoc: Avoiding IDC4 links | 
| 441873 | Delete links: Reduce database accesses | 
| 384660 | Preventing the update of links | 
| 360536 | Problems with Report RSRLDREL when deleting links | 
| 313853 | Poor performance during link display | 
| 149367 | IDoc: Link and archiving |