오라클 히든 파라미터
DB CAFE
- DBA { Oracle DBA 명령어 > DBA 초급 과정 > DBA 고급 과정 }
- 튜닝 { 오라클 튜닝 목록 }
- 모델링 { 데이터 모델링 가이드 }
목차
- 1 _optim_peek_user_binds
- 2 _optimizer_use_feedback
- 3 _add_col_optim_enabled
- 4 _optimizer_aggr_groupby_elim
- 5 _optimizer_reduce_groupby_key
- 6 _add_col_optim_enabled
- 7 _b_tree_bitmap_plans
- 8 _cleanup_rollback_entries
- 9 _clusterwide_global_transactions
- 10 _complex_view_merging
- 11 _datafile_write_errors_crash_inst
- 12 _db_mttr_advice
- 13 _diag_daemon
- 14 _dump_rcvr_ipc
- 15 _enable_minscn_cr
- 16 _gc_maximum_bids
- 17 _gc_policy_time
- 18 _gc_undo_affinity
- 19 _in_memory_undo
- 20 _kgl_large_heap_warning_thresh
- 21 _library_cache_advice
- 22 _memory_imm_mode_without_a
- 23 _nlj_batching_enabled
- 24 _nlj_batching_misses_enabled
- 25 _optimizer_adaptive_cursor_sharing
- 26 _optimizer_extended_cursor_sharing
- 27 _PX_use_large_pool
- 28 _row_cache_cursors
- 29 _smm_advice_enabled
- 30 _trace_files_public
- 31 _undo_autotune
- 32 오라클 히든 파라메터 조회
1 _optim_peek_user_binds[편집]
alter system set "_optim_peek_user_binds" = false scope=both;
. Bind variable peeking(바인드변수 엿보기) 기능 활서 여부 . Bind Peeking : Bind 변수를 포함하는 SQL문이 최초로 실행될 때 Bind 변수값을 이용해서 실행계획을 수립하는 기능 => Bind Peeking에 따른 잘못된 실행계획이 수립되는 것을 방지하기 위해 false 로 설정 권고
2 _optimizer_use_feedback[편집]
. 쿼리의 최초 실행 시 예측 건수와 실제 건수의 차이가 크면 opt_estimate 힌트의 형태로 쿼리가 변경되도록 함 => 의도되지 않은 SQL 실행계획 유발의 우려가 있으므로 false로 설정 권고
3 _add_col_optim_enabled[편집]
. column add 시 dictionary만 update 하고 이후 insert 시 해당 컬럼이 생성 => 권고: wrong result scale로 인해 false(참고 : 19183343.8)
4 _optimizer_aggr_groupby_elim[편집]
. group-by and aggregation elimination 기능의 활성화 여부 => 권고 : wrong result 발생으로 false(참고 : 19567916.8, 1924440.1)
5 _optimizer_reduce_groupby_key[편집]
. Group by key reduction => 권고 : wrong result 발생으로 false(참고 : 19567916.8, 1924440.1)
6 _add_col_optim_enabled[편집]
Allows new add column optimization FALSE 설정 Def. = TRUE
7 _b_tree_bitmap_plans[편집]
enable the use of bitmap plans for tables w. only B-tree indexes FALSE 설정 Def. = TRUE
8 _cleanup_rollback_entries[편집]
no. of undo entries to apply per transaction cleanup 2000 설정
Def. = 100
9 _clusterwide_global_transactions[편집]
enable/disable clusterwide global transactions FALSE 설정 Def. = TRUE
10 _complex_view_merging[편집]
enable complex view merging FALSE 설정 Def. = TRUE
11 _datafile_write_errors_crash_inst[편집]
ance datafile write errors always crash instance FALSE 설정 Def. = TRUE
12 _db_mttr_advice[편집]
MTTR advisory OFF 설정 Def. = ON
13 _diag_daemon[편집]
start DIAG daemon FALSE 설정 Def. = TRUE
14 _dump_rcvr_ipc[편집]
if TRUE enables IPC dump at instance eviction time FALSE 설정 Def. = TRUE
16 _gc_maximum_bids[편집]
maximum number of bids which can be prepared 4 설정 Def. = 0
17 _gc_policy_time[편집]
how often to make object policy decisions in minutes 0 설정 Def. = 10
18 _gc_undo_affinity[편집]
if TRUE, enable dynamic undo affinity FALSE 설정 Def. = TRUE
19 _in_memory_undo[편집]
Make in memory undo for top level transactions FALSE 설정 Def. = TRUE
20 _kgl_large_heap_warning_thresh[편집]
old maximum heap size before KGL writes warnings to the alert log 33554432 설정
21 _library_cache_advice[편집]
whether KGL advice should be turned on FALSE 설정 Def. = TRUE
22 _memory_imm_mode_without_a[편집]
utosga Allow immediate mode without sga/memory target FALSE 설정 Def. = TRUE
23 _nlj_batching_enabled[편집]
enable batching of the RHS IO in NLJ 0 설정 Def. = 1
24 _nlj_batching_misses_enabled[편집]
enable exceptions for buffer cache misses 0 설정 Def. = 1
25 _optimizer_adaptive_cursor_sharing[편집]
optimizer adaptive cursor sharing FALSE 설정 Def. = TRUE
26 _optimizer_extended_cursor_sharing[편집]
optimizer extended cursor sharing NONE 설정 Def. = UDO
27 _PX_use_large_pool[편집]
Use Large Pool as source of PX buffers TRUE 설정 Def. = FALSE
29 _smm_advice_enabled[편집]
if TRUE, enable v$pga_advice FALSE 설정 Def. = TRUE
30 _trace_files_public[편집]
Create publicly accessible trace files TRUE 설정 Def. = FALSE
32 오라클 히든 파라메터 조회[편집]
--
-- List all hidden database parameters.
--
SET PAUSE ON
SET PAUSE 'Press Return to Continue'
SET PAGESIZE 60
SET LINESIZE 300
COLUMN ksppinm FORMAT A50
COLUMN ksppstvl FORMAT A50
SELECT
ksppinm,
ksppstvl
FROM
x$ksppi a,
x$ksppsv b
WHERE
a.indx=b.indx
AND
substr(ksppinm,1,1) = '_'
ORDER BY ksppinm
/
-- SYS 로 Login:
select a.ksppinm name, b.ksppstvl value
from
x$ksppi a,
x$ksppsv b
WHERE
a.indx=b.indx
and a.ksppinm like '%bloom%';