~~~~~~~~~~Per Second Per Transaction
Redo size:
Logical reads:
Block changes:
Physical reads:
Physical writes:
User calls:
Parses:
Hard parses:
Sorts:
Logons:
Executes:
Transactions:
% Blocks changed per Read:
Rollback per transaction %:
Instance Efficiency Percentages (Target
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %:
Buffer Hit %:
Library Hit %:
Execute to Parse %:
Parse CPU to Parse Elapsd %:
如果一個經常訪問的列上的索引被刪除
Shared Pool Statistics
Begin End
Memory Usage %:
% SQL with executions>
% Memory for SQL w/exec>
Top
~~~~~~~~~~~~~~~~~~ % Total
Event Waits Time (s) Ela Time
CPU time
db file sequential read
db file scattered read
buffer busy waits
log file sync
TIMED_STATISTICS = TRUE 那麼等待事件按等待的時間排序
= FALSE那麼事件按等待的數量排序
常見事件
LOG FILE SYNC: 在每次提交時都出現
db file sequential read: 在單個數據塊上大量等待
DB_CACHE_SIZE: 可以決定該事件出現的頻率
db file scattered read : 意味著等待於全表掃描有關系
buffer busy wait: 當緩沖區以一種非共享方式或者如正在被讀入到緩沖時
latch free: 常跟應用沒有很好的應用綁定有關
Enqueue : 最有可能是多個用戶同時修改同一個塊
logfile switch: 通常是因為歸檔速度不夠快
log buffer space: 日志緩沖區寫的速度快於LGWR寫REDOFILE的速度
TOP SQL
調整首要的
Instance Activity Stats for DB: CRMTEMP Instance: crmtemp Snaps:
Statistic Total per Second per Trans
CPU used by this session
CPU used when call started
CR blocks created
Cached Commit SCN referenced
Commit SCN cached
DBWR buffers scanned
DBWR checkpoint buffers written
DBWR checkpoints
dirty buffers inspected
free buffer inspected
sorts (disk)
sorts (memory)
sorts (rows)
summed dirty queue length
From:http://tw.wingwit.com/Article/program/Oracle/201311/18914.html