QUESTION 63
Examine the parameter setting in your database:
SQL> SHOW PARAMETER TARGET
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target integer 0
db_flashback_retention_target integer 1440
fast_start_io_target integer 0
fast_start_mttr_target integer 0
memory_max_target big integer 808M
memory_target big integer 808M
pga_aggregate_target big integer 0
sga_target big integer 0
SQL> SHOW PARAMETE SGA_MAX_SIZE
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sga_max_size big integer 808M
Which statement is correct about the database?
A. Automatic memory management is disabled because PGA_AGGREGATE_TARGET and SGA_TARGET
are not set
B. The instance is started but the database will not be opened until PGA_AGGREGATE_TARGET and
SGA_TARGET are set
C. The database is opened but users cannot perform transactions until PGA_AGGREGATE_TARGET and
SGA_TARGET are set
D. Automatic memory management is enabled and, as perpolicy, 60% of the memory for System Global Area
(SGA) and 40% of the memory for Program Global Area (PGA)will be distributed at startup
Answer: D
同640题：http://blog.csdn.net/rlhua/article/details/12494633
Explanation/Reference:
Section: Managing Database Performance & Tuning
Not sure about the policy stuff, but it's the default behavior when memory_target and memory_max_target are
set, sga_max_target is always set automatically to the same value as memory_max_target
http://download.oracle.com/docs/cd/B14117_01/server.101/b10752/memory.htm#47750
Configuring Automatic PGA Memory
When configuring a brand new instance, it is hard to know precisely the appropriate setting for
PGA_AGGREGATE_TARGET. You can determine this setting in three stages:
Make a first estimate for PGA_AGGREGATE_TARGET, based on a rule of thumb. By default, Oracle
uses
20% of the SGA size. However, this initial setting may be too low for a large DSS system.
Run a representative workload on the instance and monitor performance, using PGA statistics collected
by Oracle, to see whether the maximum PGA size is under-configured or over-configured.
Tune PGA_AGGREGATE_TARGET, using Oracle PGA advice statistics.