Oracle 9i,10g,11g 隐藏参数：

SELECT a.ksppinm Param,

b.ksppstvl SessionVal,

c.ksppstvl InstanceVal,

a.ksppdesc Descr

FROM x$ksppi a, x$ksppcv b, x$ksppsv c

WHERE a.indx = b.indx

AND a.indx = c.indx

AND a.ksppinm LIKE '/_%' ESCAPE '/'

ORDER BY 1

/

12c 隐藏参数查看：

SELECT ksppinm, ksppdesc

FROM x$ksppi

WHERE subsur (ksppinm, 1, 1) = '_'

ORDER BY 1, 2

/

_4030_dump_bitvec bitvec to specify dumps prior to 4030 error

_4031_dump_bitvec bitvec to specify dumps prior to 4031 error

_4031_dump_interval Dump 4031 error once for each n-second interval

_4031_max_dumps Maximum number of 4031 dumps for this process

_4031_sga_dump_interval Dump 4031 SGA heapdump error once for each n-second interval

_4031_sga_max_dumps Maximum number of SGA heapdumps

_ILM_FILTER_TIME Upper filter time for ILM block compression

_ILM_FILTER_TIME_LOWER Lower filter time for ILM block compression

_ILM_POLICY_NAME User specified ILM policy name

_NUMA_instance_mapping Set of nodes that this instance should run on

_NUMA_pool_size aggregate size in bytes of NUMA pool

_PX_use_large_pool Use Large Pool as source of PX buffers

__data_transfer_cache_size Actual size of data transfer cache

...........