prscpu:cpu time parsing
prsela:elapsed time parsing
prsdsk:number of disk reads during parse
prsqry:number of buffers for consistent read during parse
prscu:number of buffers for current read during parse
prsmis:number of misses in library cache during parse
execnt:number of execute was called
execpu:cpu time spent executing
exeela:elapsed time executing
exedsk:number of disk reads during execute
exeqry:number of buffers for consistent read during execute
execu:number of buffers for current read during execute
exerow:number of rows processed during execute
exemis:number of library cache misses during execute
fchcnt:number of times fetch was called
fchcpu:cpu time spent fetching
fchela:elapsed time fetching
fchdsk:number of disk reads during fetch
fchqry:number of buffers for consistent read during fetch
fchcu:number of buffers for current read during fetch
fchrow:number of rows fetched
userid:userid of user that parsed the cursor
REM statement as your needs dictate.
CREATE TABLE tkprof_table
(
date_of_insert DATE
,cursor_num NUMBER
,depth NUMBER
,user_id NUMBER
,parse_cnt NUMBER
,parse_cpu NUMBER
,parse_elap NUMBER
,parse_disk NUMBER
,parse_query NUMBER
,parse_current NUMBER
,parse_miss NUMBER
,exe_count NUMBER
,exe_cpu NUMBER
,exe_elap NUMBER
,exe_disk NUMBER
,exe_query NUMBER
,exe_current NUMBER
,exe_miss NUMBER
,exe_rows NUMBER
,fetch_count NUMBER
,fetch_cpu NUMBER
,fetch_elap NUMBER
,fetch_disk NUMBER
,fetch_query NUMBER
,fetch_current NUMBER
,fetch_rows NUMBER
,ticks NUMBER
,sql_statement LONG
);
INSERT INTO tkprof_table VALUES
(
SYSDATE, 1, 0, 61, 1, 0, 418, 0, 0, 0, 1
, 1, 15625, 1435, 0, 0, 0, 0, 0
, 4, 0, 4417, 0, 24, 0, 36, 13450151
, ’select * from tblinventoryhistory
‘);
alter session set events '10046 trace name context forever,level 12';
select * from tblinventoryhistory ;
select * from tblorder ;
select * from tblproduct ;
select * from tbluser ;
select * from tblroute ;
——- —————————————————
0 SELECT STATEMENT GOAL: CHOOSE
0 TABLE ACCESS (FULL) OF 'TBLROUTE'
2 p.spid || '.trc' trace_file_name
3 from (select p.spid
4 from sys.v$mystat m, sys.v$session s, sys.v$process p
5 where m.statistic# = 1
6 and s.sid = m.sid
7 and p.addr = s.paddr) p,
8 (select t.instance
9 from sys.v$thread t, sys.v$parameter v
10 where v.name = 'thread'
11 and (v.value = 0 or t.thread# = to_number(v.value))) i,
12 (select value from sys.v$parameter where name = 'user_dump_dest') d;
——————————————————————————–
/opt/oracle/admin/hsjf/udump/hsjf_ora_1026.trc
注意:最後排序是按照各個選項的數字之和進行排序,類似於order by (sort1+sort2+sort3),而不是order by sort1,sort2,sort3
oracle性能優化:如何讀懂tkprof
CALL :每次SQL語句的處理都分成以下三個部分
Parse:這步將SQL語句轉換成執行計劃,包括檢查是否有正確的授權和所需要用到的表、列以及其他引用到的對象是否存在。
Execute:這步是真正的由Oracle來執行語句。對於insert、update、delete操作,這步會修改數據,對於select操作,這步就只是確定選擇的記錄。
Fetch:返回查詢語句中所獲得的記錄,這步只有select語句會被執行。
COUNT:這個語句被parse、execute、fetch的次數。
CPU:這個語句對於所有的parse、execute、fetch所消耗的cpu的時間,以秒爲單位。
ELAPSED:這個語句所有消耗在parse、execute、fetch的總的時間。
DISK:從磁盤上的數據文件中物理讀取的塊的數量。一般來說更想知道的是正在從緩存中讀取的數據而不是從磁盤上讀取的數據。
QUERY:在一致性讀模式下,所有parse、execute、fetch所獲得的buffer的數量。一致性模式的buffer是用於給一個長時間運行的事務提供一個一致性讀的快照,緩存實際上在頭部存儲了狀態。
CURRENT:在current模式下所獲得的buffer的數量。一般在current模式下執行insert、update、delete操作都會獲取buffer。在current模式下如果在高速緩存區發現有新的緩存足夠給當前的事務使用,則這些buffer都會被讀入了緩存區中。
ROWS: 所有SQL語句返回的記錄數目,但是不包括子查詢中返回的記錄數目。對於select語句,返回記錄是在fetch這步,對於insert、update、delete操作,返回記錄則是在execute這步。
B、Parse count/Execute count parse count應儘量接近1,如果太高的話,SQL會進行不必要的reparse
C、rows Fetch/Fetch Fetch Array的大小,太小的話就沒有充分利用批量Fetch的功能,增加了數據在客戶端和服務器之間的往返次數。
D、disk/query+current 磁盤IO所佔邏輯IO的比例,太大的話有可能是db_buffer_size過小(也跟SQL的具體特性有關)
E、elapsed/cpu 太大表示執行過程中花費了大量的時間等待某種資源
F、cpu Or elapsed 太大表示執行時間過長,或消耗了了大量的CPU時間,應該考慮優化
G、執行計劃中的Rows 表示在該處理階段所訪問的行數,要儘量減少
alter session set timed_statistics=true;
alter session set events '10046 trace name context forever, level 12';
select 'Hello, world; today is '||sysdate from dual; exit;