Ora-600 encountered in Oracle environment [qkacon: fjswrwo]

In the near future , An error is reported in the database environment of a user ORA-00600: internal error code, arguments: [qkacon:FJswrwo], [3]. about ORA-00600 Report errors , stay MOS The last query is related to a BUG The description is more consistent with .ORA-600 [qkacon:FJswrwo] Using CONNECT BY (Doc ID 1070636.1).

The document mentions the way of patching or modifying implicit parameters to deal with ; The business needs to be stopped when patching , Greater impact ;

Tried to modify the implicit parameters , No error will be reported in this case , The application system returns to normal . The relevant information is as follows ：

ORA-00600: internal error code, arguments: [qkacon:FJswrwo], [3], [], [], [], [], [], [], [], [], [], []
The partial call stack may contain:
kgeasnmierr qkacon qkaqkn qkadrv qkadrv opitca kksLoadChild kxsGetRuntimeLock kksfbc kkspsc0 kksParseCursor opiosq0 kpooprx kpoal8

CAUSE
Bug 9105678 CONNECT BY QUERY FAILED WITH ORA-600 [QKACON:FJSWRWO]
This occurs when running a query which has a connect-by view and contains() function in the outer query
blocks of the view.

SOLUTION
To implement solution please do the following:
1. Install Patch 9105678 if available for your platform and DB version
2. Use the workaround:
alter session set "_optimizer_connect_by_cost_based" = false;
3. This bug is fixed in 12.1.