Easy way to crash a Oracle 10.2 session
This query crashes the session when it’s run or parsed.
I haven’t checked if this appears in other versions or not.
SQL> conn scott/tiger@orcl
Connected.
SQL> select * from v$version;
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 – 64bi
PL/SQL Release 10.2.0.3.0 – Production
CORE 10.2.0.3.0 Production
TNS for Solaris: Version 10.2.0.3.0 – Production
NLSRTL Version 10.2.0.3.0 – Production
SQL> explain plan for with q as
2 (select ‘x’ d from dual
3 union all
4 select ‘y’ from dual)
5 select d from q
6 union all
7 select d from q
8 order by dbms_random.value;
explain plan for with q as (select ‘x’ d from dual
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
The crashes happened when I added the “order by dbms_random.value”. The problem seems to be in the optimiser since I get the same results whether I run the query or just explain it. Possibly something to do with the optimiser wrongly assuming the random function is deterministic?
There’s a simple workaround, so I’m not too worried. I just change it to this and it works fine:
with q as
(select ‘x’ d from dual
union all
select ‘y’ from dual)
select d, dbms_random.value o from q
union all
select d, dbms_random.value o from q
order by o;
About Jeffrey Kemp
Application Designer & Developer at Oracle specialising in Oracle APEX (Application Express), Oracle SQL and PL/SQL. Oracle ACE Alumni ♠️. Piano player, father, husband, Christian. The views expressed on this blog are my own and do not necessarily reflect the views of Oracle.