The shadow instance was introduced in the new upgrade procedure for upgrades to Basis Release 610 or higher.
It will be installed in the same database (parallel to the productive instance).
It runs on the target release with the target release kernel or as a copy of the original system in EHP installation scenario.
The shadow instance is active during upgrade phases MAIN_SHDPREPUT/* MAIN_SHDRUN/*
The functions of the shadow instance are limited:
- Lock prevents to logon to the shadow instance with a user other then DDIC .
If you are trying to logon as a user other then user DDIC you may get error " Upgrade still running: Logon not possible".
Please follow the SAP KBA 2048823
f you are trying to unlock the shadow instance with the command " SAPup unlockshd" and you get the message:
At this time of the procedure, the shadow instance does not yet exist since you are before phase START_SHDI_*!
At this time of the procedure, the shadow instance does not exist anymore since you are passed phase STOP_SHDI_*!"
- The system only allows accesses to the table contents of SAP standard Basis tables.
Application transactions, customer programs cannot be executed, you can get DBSQL_SQL_ERROR or SYNTAX_ERROR short dumps, which is normal.
See also SAP KBAs 2148302, 2220206 and 1940870.
- Note that you must not carry out activation using transaction SE11 in the shadow system. The activation is carried out in the background by the ACT_UPG phase .
To do this, execute the phase and repeat if an error occurs. See also SAP note 2050604 .
- It is not possible to execute "tp import" in the shadow instance.
Related SAP notes/KBAs
398100 - Shadow instance during upgrade
2220206 - ACT_UPG: ORA-00942: table or view does not exist calling SPDD in shadow instance
2148302 - Missing tables in the Shadow Instance
1940870 - DBIF_RSQL_TABLE_UNKNOWN error occurs when running transaction SPAU on the shadow system
2050604 - Problem analysis in upgrade: Phase ACT_UPG
2048823 - Upgrade still running: Logon not possible / User DDIC may not make changes in customer systems
2244827 - SUM or SAPup in an execution phase (e.g. PARCONV_UPG, XPRAS_AIMMRG) error: Upgrade still running: Logon not possible
SCN Blog SUM: introduction to shadow system