Failed to upgrade PE from 520 to 521

RPCHandler PEServer.init DB=OSDS [Error] FNRPE1210001000E Database upgrade failed; Exception: Database error.  See chained exception
; Cannot execute statement, msecs=, SQL: "CREATE UNIQUE INDEX DB2INST1.VW_IND6 ON DB2INST1.VWLog1_113 (F_WorkFlowNumber, F_EventType, F_TimeStamp, F_SeqNumber)"
at filenet.jpe.database.DbDesc.MapDB2Error(DbDesc.java:1288)
at filenet.jpe.database.DbDesc.ConvertError(DbDesc.java:1132)
at filenet.jpe.database.DbStatement.convertError(DbStatement.java:221)
at filenet.jpe.database.DbStatement.execute(DbStatement.java:142)
at filenet.jpe.rpc.appserver.PEEngineServlet$ServerStartupThread.run(PEEngineServlet.java:120)
Caused by: com.ibm.db2.jcc.am.SqlException: DB2 SQL Error: SQLCODE=-954, SQLSTATE=57011, SQLERRMC=null, DRIVER=3.65.77
at com.ibm.db2.jcc.am.cd.a(cd.java:701)
at com.ibm.db2.jcc.am.cd.a(cd.java:60)

Manually run the sql , then found the application heap size was not enough, so just increase application heap size as:
db2 update db cfg for OSDB using APPLHEAPSZ 256000