https://userapps.support.sap.com/sap/support/knowledge/en/1875249
1875249 - Upgrade errors in DBCLONE phase - table D345T | SAP Knowledge Base Article
While performing a SAP system upgrade, an error takes place in DBCLONE phase, related to the copying of table D345T data:...
https://userapps.support.sap.com/sap/support/knowledge/en/2779530
2779530 - SUM DBCLONE error "cannot use duplicate index name" | SAP Knowledge Base Article
During a database copy with SUM using DBCLONE, the process ends with errors similar to: 3 error(s) during parallel execution of processes, check...
https://userapps.support.sap.com/sap/support/knowledge/en/3345953
3345953 - SPS upgrade failed with error in SUM phase MAIN_SHDCRE/SUBMOD_SHDDBCLONE/DBCLONE - SAP...
https://userapps.support.sap.com/sap/support/knowledge/en/3047936
3047936 - Upgrade phase "DBCLONE" aborted with severe errors. Database table is inconsistent due to...
In SAPup.log you can see the following: CURRENTPHASE MAIN_SHDCRE/SUBMOD_SHDDBCLONE/DBCLONE # Error message set: '8 errors during parallel execution of...