Using the Client Result Cache

Question

Hello everyone,
I have a question regarding the use of the client result cache but first of all here are the informations about my database:
SQL> SELECT * FROM v$version;
BANNER
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
CORE    11.2.0.1.0    Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
I have installed the Oracle Client Tools on my clientmachine. It has a tnsnames.ora like this:
ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = FEA11-119SRV)(PORT = 1521))
    (CONNECT_DATA =
      (SERVICE_NAME = orcl.local)
The Client Result Cache is configured in the sqlnet.ora.
ADR_BASE = /u01/app/oracle
OCI_RESULT_CACHE_MAX_SIZE= 2048000
OCI_RESULT_CACHE_MAX_RSET_SIZE = 1024000
NAMES.DIRECTORY_PATH = (EZCONNECT, TNSNAMES, HOSTNAME)
The Databaseserver is configured like that:
SQL> col name format a30
SQL> col value format a30
SQL> SELECT name, value
  2  FROM   v$system_parameter
  3  WHERE  name LIKE '%result_cache%';
NAME                   VALUE
result_cache_mode           MANUAL
result_cache_max_size           0
result_cache_max_result        5
result_cache_remote_expiration 0
client_result_cache_size       1073741824
client_result_cache_lag        3000
After configuring client an server I try the followign SQL-Statement on the clientmachine:
sqlplus oracle/password@orcl
set autotrace traceonly explain
SELECT /*+ result_cache */ *
FROM testtable;
SQL
The execution plan show two operations: "SELECT STATEMENT" and "TABLE ACCESS FULL" but no the "RESULT CACHE" operation.
Did I miss something?
Any help would be appreciated
Florian W.

Answer 1

result_cache_max_size           0
That means the result cache is disabled. You need to set it to a non-zero value. That is the maximum ammount of memory, in bytes, the database will allocate on the shared pool to dedicate it to the result cache for all requests.
By the way, OCI_RESULT_CACHE_MAX_SIZE is optional. By default the sessions will have the maximum size they can occupy on the cache determined by CLIENT_RESULT_CACHE parameter, the client (OCI) side parameters override that.
result_cache_mode           MANUAL
Another thing to consider is RESULT_CACHE_MODE in MANUAL, that will cause only the statements with the RESULT_CACHE hint on it to be cached on the result cache. You can also set result cache to mode FORCE on specific tables with alter table command.
Regards