Note: Oracle hidden parameters are undocumented and unsupported by Oracle.
Make sure that you thoroughly test all hidden parameters before placing them in your production environment.
查询语句：
SELECT
ksppinm "Parameter Name",
ksppstvl "Value",
ksppdesc "Description"
FROM
x$ksppi x,
x$ksppcv y
WHERE
x.indx = y.indx
AND x.inst_id = userenv('Instance')
AND y.inst_id = userenv('Instance')
AND ksppinm LIKE '要查的参数名称%';
Parameter Name Value Description
----------------------------------- ---------- --------------------------------------------------------------------------------
_allow_error_simulation FALSE Allow error simulation for testing
_allow_resetlogs_corruption FALSE allow resetlogs even if it will cause corruption
_allow_terminal_recovery_corruption FALSE Finish terminal recovery even if it may cause corruption
_allow_read_only_corruption FALSE allow read-only open even if database is corrupt
_allow_drop_snapshot_standby_grsp FALSE Allow dropping snapshot standby guaranteed restore point
_allow_drop_ts_with_grp FALSE Allow drop Tablespace with guaranteed restore points
_allow_compatibility_adv_w_grp FALSE allow advancing DB compatibility with guaranteed restore points
_allow_commutativity TRUE allow for commutativity of +, * when comparing expressions
_allow_level_without_connect_by FALSE allow level without connect by
_allow_cell_smart_scan_attr TRUE Allow checking smart_scan_capable Attr
_corrupted_rollback_segments NULL corrupted undo segment list
_minimum_giga_scn NULL Minimum SCN to start with in 2^30 units 11 #在11.2.0.2打上相关的scn补丁以及后续版本已经废除
