隱藏參數 (hidden parameters) ，由oracle內部使用，以 ‘_‘ 開頭。

可以通過以下兩種方式查看所有隱藏參數：

1. SELECT i.ksppinm name,
2. i.ksppdesc description,
3. CV.ksppstvl VALUE,
4. CV.ksppstdf isdefault,
5. DECODE (BITAND (CV.ksppstvf, 7),
6. 1, ‘MODIFIED‘,
7. 4, ‘SYSTEM_MOD‘,
8. ‘FALSE‘)
9. ismodified,
10. DECODE (BITAND (CV.ksppstvf, 2), 2, ‘TRUE‘, ‘FALSE‘) isadjusted
11. FROM sys.x$ksppi i, sys.x$ksppcv CV
12. WHERE i.inst_id = USERENV (‘Instance‘)
13. AND CV.inst_id = USERENV (‘Instance‘)
14. AND i.indx = CV.indx
15. AND i.ksppinm LIKE ‘/_%‘ ESCAPE ‘/‘
16. ORDER BY REPLACE (i.ksppinm, ‘_‘, ‘‘);

1. SELECT ksppinm, ksppstvl, ksppdesc
2. FROM x$ksppi x, x$ksppcv y
3. WHERE x.indx = y.indx AND TRANSLATE (ksppinm, ‘_‘, ‘#‘) LIKE ‘#%‘;

示例：如果想查看_db_block_hash_buckets的參數值

1. SELECT ksppinm, ksppstvl, ksppdesc
2. FROM x$ksppi x, x$ksppcv y
3. WHERE x.indx = y.indx AND ksppinm = ‘_db_block_hash_buckets‘;

oracle 查看隱藏參數