20.8.18

ORA-02051 Another Session Or Branch In Same Transaction Failed

ORA-02051 Another Session Or Branch In Same Transaction Failed (Doc ID 2253226.1)         

SYMPTOMS for ORA-02051 Another Session Or Branch In Same Transaction Failed.
Database performance is slow and caused   the transactions ORA-02051 another session or branch in same transaction failed or finalized

CAUSE for ORA-02051 Another Session Or Branch In Same Transaction Failed.
Session transactions branches caused the issue Excessive Waits On The Event "Global transaction acquire instance locks"

SOLUTION
Please use below sql and identified underscore parameter values for ORA-02051 Another Session Or Branch In Same Transaction Failed :
SQL>
select a.ksppinm "Parameter", b.ksppstvl "Session Value",c.ksppstvl "Instance Value"  FROM x$ksppi a,x$ksppcv b, x$ksppsv c  WHERE a.indx = b.indx AND a.indx = c.indx AND a.ksppinm LIKE '/_%' escape '/'  AND (a.ksppinm like '%clusterwide_global%' or a.ksppinm like '%disable_autotune_gtx%') ;

output:-

Parameter                                                          Session Value         Instance Value
----------------------------------------             -------------------- --------------------
_clusterwide_global_transactions             TRUE                              TRUE
_disable_autotune_gtx                                  FALSE                             FALSE


Set following to solver ORA-02051 Another Session Or Branch In Same Transaction Failed :-
alter system set "_clusterwide_global_transactions"=false scope=spfile;
alter system set "_disable_autotune_gtx"=TRUE scope = spfile;  

Note:-  bounce the instances for the changes to take effect

Oracle Mean company, not database :)