Find hidden initialization parameter values

Today, hit "ORA-00600: internal error code, arguments: [20022], [2], [], [], [], [], [], []". Find this blog on the web that described the same situation. Basically it is due to _b_tree_bitmap_plans=TRUE. Metalink has a note 378117.1 about it.


The following query can be used to check the hidden parameter values:

col name format a30
col description format a40
col session_value format a10
col system_value format a10

select
   a.ksppinm  name,
   a.ksppdesc DESCRIPTION,
   b.ksppstvl SESSION_VALUE,
   c.ksppstvl SYSTEM_VALUE
from x$ksppi a, x$ksppcv b, x$ksppsv c
where a.indx = b.indx
 and a.indx = c.indx
 and a.ksppinm like '%tree%';

For examples:

In 9i:

NAME                           DESCRIPTION                              SESSION_VA SYSTEM_VAL
------------------------------ ---------------------------------------- ---------- ----------
_dump_qbc_tree                 dump top level query parse tree to trace 0          0
_b_tree_bitmap_plans           enable the use of bitmap plans for table TRUE       TRUE
                               s w. only B-tree indexes


In 10g:
NAME                           DESCRIPTION                              SESSION_VA SYSTEM_VAL
------------------------------ ---------------------------------------- ---------- ----------
_dump_qbc_tree                 dump top level query parse tree to trace 0          0
_b_tree_bitmap_plans           enable the use of bitmap plans for table TRUE       TRUE
                               s w. only B-tree indexes

_dtree_area_size               size of Decision Tree Classification wor 131072     131072
                               k area

_dtree_pruning_enabled         Decision Tree Pruning Enabled            TRUE       TRUE
_dtree_compressbmp_enabled     Decision Tree Using Compressed Bitmaps E TRUE       TRUE
                               nabled

_dtree_binning_enabled         Decision Tree Binning Enabled            TRUE       TRUE
_dtree_max_surrogates          maximum number of surrogates             1          1
_dtree_bintest_id              Decision Tree Binning Test ID            0          0
_outline_bitmap_tree           BITMAP_TREE hint enabled in outline      TRUE       TRUE

To change the value of hidden parameter at session level, I found I have to use double quotation mark, i.e.
alter session set "_b_tree_bitmap_plans"=false;