監控資料庫效能的sql
檢視tablespace的空間使用情況
select
tablespace_name,
sum(bytes)
/1024
/1024
from
dba_free_space
group
bytablespace_name
1. 監控事例的等待
select
event,
sum(decode(wait_time,0,
0,1)) "prev",
sum(decode(wait_time,0,
1,0)) "curr",
count(*
) "tot"
from
v$session_wait
group
byevent
orderby4
; 2. 回滾段的爭用情況
select
name, waits, gets, waits
/gets "ratio"
from
v$rollstat a, v$rollname b
where
a.usn
=b.usn;
3. 監控表空間的 i
/o 比例
select
df.tablespace_name name,df.
file_name
"file
",f.phyrds pyr,
f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw
from
v$filestat f, dba_data_files df
where
f.file# =
df.file_id
order
bydf.tablespace_name;
4. 監控檔案系統的 i
/o 比例
select
substr(a.
file#,1
,2) "#", substr(a.name,1,
30) "name",
a.status, a.bytes, b.phyrds, b.phywrts
from
v$datafile a, v$filestat b
where
a.file# =
b.file
#; 5
.在某個使用者下找所有的索引
select
user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
from
user_ind_columns, user_indexes
where
user_ind_columns.index_name
=user_indexes.index_name
anduser_ind_columns.table_name
=user_indexes.table_name
order
byuser_indexes.table_type, user_indexes.table_name,
user_indexes.index_name, column_position;
6. 監控 sga 的命中率
select
a.value
+b.value "logical_reads", c.value "phys_reads",
round
(100
*((a.value
+b.value)
-c.value)
/(a.value
+b.value)) "buffer hit ratio"
from
v$sysstat a, v$sysstat b, v$sysstat c
where
a.statistic# =38
andb.statistic# =39
andc.statistic# =40
; 7. 監控 sga 中字典緩衝區的命中率
select
parameter, gets,getmisses , getmisses
/(gets
+getmisses)
*100
"miss ratio", (1
-(sum(getmisses)/(
sum(gets)
+sum
(getmisses))))
*100
"hit ratio"
from
v$rowcache
where
gets
+getmisses
<>
0group
byparameter, gets, getmisses;
8. 監控 sga 中共享快取區的命中率，應該小於1
%select
sum(pins) "total pins",
sum(reloads) "total reloads",
sum(reloads)
/sum
(pins)
*100
libcache
from
v$librarycache;
select
sum(pinhits
-reloads)
/sum
(pins) "hit radio",
sum(reloads)
/sum
(pins) "reload
percent
" from
v$librarycache;
9. 顯示所有資料庫物件的類別和大小
select
count
(name) num_instances ,type ,
sum(source_size) source_size ,
sum(parsed_size) parsed_size ,
sum(code_size) code_size ,
sum(error_size) error_size,
sum(source_size)
+sum
(parsed_size)
+sum
(code_size)
+sum
(error_size) size_required
from
dba_object_size
group
bytype
orderby2
; 10
. 監控 sga 中重做日誌快取區的命中率，應該小於1
%select
name, gets, misses, immediate_gets, immediate_misses,
decode(gets,0,
0,misses
/gets
*100
) ratio1,
decode(immediate_gets
+immediate_misses,0,
0, immediate_misses
/(immediate_gets
+immediate_misses)
*100
) ratio2
from
v$latch
where
name in(
'redo allocation',
'redo copy
');
11. 監控記憶體和硬碟的排序比率，最好使它小於 .
10，增加 sort_area_size
select
name, value
from
v$sysstat
where
name in(
'sorts (memory)',
'sorts (disk)
');
12. 監控當前資料庫誰在執行什麼sql語句
select
osuser, username, sql_text
from
v$session a, v$sqltext b
where
a.sql_address
=b.address
order
byaddress, piece;
MySQL 資料庫 效能監控
show status flush status 檢視當前連線數 show status like thread thread cached 被快取的執行緒的個數 thread running 處於啟用狀態的執行緒的個數 thread connected 當前連線的執行緒的個數 thread cre...
MySQL 資料庫 效能監控
show status flush status 檢視當前連線數 show status like thread thread cached 被快取的執行緒的個數 thread running 處於啟用狀態的執行緒的個數 thread connected 當前連線的執行緒的個數 thread cre...
資料庫SQL效能查詢
作為乙個開發 測試人員，或多或少都得和資料庫打交道，而對資料庫的操作歸根到底都是sql語句，所有操作到最後都是運算元據，那麼對sql效能的掌控又成了我們工作中一件非常重要的工作。下面簡單介紹下一些檢視oracle效能的一些實用方法 1 查詢每台機器的連線數 select t.machine,coun...