3. 使用V$SHARED_POOL_ADVICE来设置shared pool的大小
V$SHARED_POOL_ADVICE displays information about estimated parse time in the shared pool for different pool sizes. The sizes range from 10% of the current shared pool size or the amount of pinned library cache memory (whichever is higher) to 200% of the current shared pool size, in equal intervals. The value of the interval depends on the current size of the shared pool.
Column Datatype Description
SHARED_POOL_SIZE_FOR_ESTIMATE NUMBER Shared pool size for the estimate (in megabytes)
SHARED_POOL_SIZE_FACTOR NUMBER Size factor with respect to the current shared pool size
ESTD_LC_SIZE NUMBER Estimated memory in use by the library cache (in megabytes)
ESTD_LC_MEMORY_OBJECTS NUMBER Estimated number of library cache memory objects in the shared pool of the specified size
ESTD_LC_TIME_SAVED NUMBER Estimated elapsed parse time saved (in seconds), owing to library cache memory objects being found in a shared pool of the specified size. This is the time that would have been spent in reloading the required objects in the shared pool had they been aged out due to insufficient amount of available free memory.
ESTD_LC_TIME_SAVED_FACTOR NUMBER Estimated parse time saved factor with respect to the current shared pool size
ESTD_LC_LOAD_TIME NUMBER Estimated elapsed time (in seconds) for parsing in a shared pool of the specified size
ESTD_LC_LOAD_TIME_FACTOR NUMBER Estimated load time factor with respect to the current shared pool size
ESTD_LC_MEMORY_OBJECT_HITS NUMBER Estimated number of times a library cache memory object was found in a shared pool of the specified size
可以使用下面的SQL语句来预估shared pool的大小：
select 'Shared Pool' component,shared_pool_size_for_estimate estd_sp_size,estd_lc_time_saved_factor parse_time_factor,case when current_parse_time_elapsed_s + adjustment_s<0then 0 else current_parse_time_elapsed_s + adjustment_s end response_timefrom (select shared_pool_size_for_estimate,shared_pool_size_factor,estd_lc_time_saved_factor,a.estd_lc_time_saved,e.value/100current_parse_time_elapsed_s,c.estd_lc_time_saved - a.estd_lc_time_saved adjustment_s from v$shared_pool_advice a,(select * from v$sysstat where) e,(select estd_lc_time_saved from v$shared_pool_advice where shared_pool_size_factor=1) c);COMPONENT ESTD_SP_SIZE PARSE_TIME_FACTOR RESPONSE_TIME-------------- ----------------- ------------------------- -------------Shared Pool 64 .9989 294.37Shared Pool 72 1 257.37Shared Pool 80 1.0009 226.37Shared Pool 88 1.0016 201.37Shared Pool 96 1.0022 181.37Shared Pool 104 1.0027 166.37Shared Pool 112 1.0029 156.37Shared Pool 120 1.0032 149.37Shared Pool 128 1.0033 144.37Shared Pool 136 1.0034 141.37Shared Pool 144 1.0034 139.37
11 rows selected.