Result Cache Oracle 11gR2

Question

Hi all,
Currently I have some problems with result cache, or maybe I don't understand this feature properly.
I'm trying to switch off the bypass mode, and I'm not able to do this:
SQL> select dbms_result_cache.status from dual;
STATUS
BYPASS
SQL> exec dbms_result_cache.bypass(FALSE);
PL/SQL procedure successfully completed.
SQL> select dbms_result_cache.status from dual;
STATUS
BYPASS
SQL> show parameter result
NAME TYPE VALUE
client_result_cache_lag big integer 3000
client_result_cache_size big integer 0
result_cache_max_result integer 5
result_cache_max_size big integer 0
result_cache_mode string MANUAL
result_cache_remote_expiration integer 0
SQL> alter system set result_cache_max_size=2M scope=both;
System altered.
SQL> show parameter result
NAME TYPE VALUE
client_result_cache_lag big integer 3000
client_result_cache_size big integer 0
result_cache_max_result integer 5
result_cache_max_size big integer 0
result_cache_mode string MANUAL
result_cache_remote_expiration integer 0
SQL> alter system set result_cache_max_size=2M scope=spfile;
System altered.
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 523108352 bytes
Fixed Size 1337632 bytes
Variable Size 465569504 bytes
Database Buffers 50331648 bytes
Redo Buffers 5869568 bytes
Database mounted.
Database opened.
SQL> show parameter result
NAME TYPE VALUE
client_result_cache_lag big integer 3000
client_result_cache_size big integer 1G
result_cache_max_result integer 5
result_cache_max_size big integer 0
result_cache_mode string MANUAL
result_cache_remote_expiration integer 0
SQL> select dbms_result_cache.status from dual;
STATUS
BYPASS
SQL> set serveroutput on;
SQL> exec dbms_result_cache.memory_report
R e s u l t C a c h e M e m o r y R e p o r t
[Parameters]
Block Size = 1K bytes
Maximum Cache Size = 0 bytes (0 blocks)
Maximum Result Size = 0 bytes (0 blocks)
[Memory]
Total Memory = 9440 bytes [0.004% of the Shared Pool]
... Fixed Memory = 9440 bytes [0.004% of the Shared Pool]
... Dynamic Memory = 0 bytes [0.000% of the Shared Pool]
PL/SQL procedure successfully completed.
SQL>
Is there something what I missed?
Thanks for any advices.
Regards,
Piotr

Answer 1

A little bit more theory:
The result cache resides in the Shared pool. Because the database was managing its memory automatically (parameter memory_target was set) and no one was working with this environment, the database didn't allocate yet enough space for shared pool to give some space for result cache. I had to set min value for shared pool to force the database to automatically allocate some space to shared pool during start up and never make shared pool smaller than specified value.
Hope that this explanation help other people :)
Regards,
Petrus