一份awr分析

http://t.askmaclean.com/thread-1484-1-1.html

10.2.0.5.0+RAC

Elapsed:                  60.32 (mins)                  
DB Time:                  582.45 (mins)                  

AAS非常高，说明负载很高

gc buffer busy         12,815,419         22,761         2         65.1        Cluster
CPU time                  7,283                  20.8         
gc cr multi block request         14,317,933         2,828         0         8.1        Cluster
db file scattered read         1,530,336         1,697         1         4.9        User I/O
db file parallel read         304,600         440         1         1.3        User I/O


gc buffer busy是主要等待事

Avg global enqueue get time (ms):         0.7
Avg global cache cr block receive time (ms):         1.0
Avg global cache current block receive time (ms):         1.2
Avg global cache cr block build time (ms):         0.0
Avg global cache cr block send time (ms):         0.0
Global cache log flushes for cr blocks served %:         3.3
Avg global cache cr block flush time (ms):         2.6
Avg global cache current block pin time (ms):         0.0
Avg global cache current block send time (ms):         0.0
Global cache log flushes for current blocks served %:         0.0
Avg global cache current block flush time (ms):         2.9


pin time +send time + flush time都不高

引起主要cluter wait time的语句是 
24,214.65        81.44        29,732.24        4,617.86        15        5q65r47cqxd2a                 DELETE FROM DA_EXAMRECORD WHER..
DELETE FROM DA_EXAMRECORD WHERE RESULT_ID=:1 AND QUESTION_ID=:2
执行15次 ， 可能涉及大表的大量删除记录

Segments by Current Blocks Received
Total Current Blocks Received: 17,738,220
Captured Segments account for 100.0% of Total
Owner        Tablespace Name        Object Name        Subobject Name        Obj. Type        Current Blocks Received        %Total
ANJIAN        ANJIAN        DA_EXAMRECORD                 TABLE        16,075,103        90.62


DA_EXAMRECORD表占 总Current Blocks Received的90%

Segments by Global Cache Buffer Busy
% of Capture shows % of GC Buffer Busy for each top segment compared
with GC Buffer Busy for all segments captured by the Snapshot
Owner        Tablespace Name        Object Name        Subobject Name        Obj. Type        GC Buffer Busy        % of Capture
ANJIAN        ANJIAN        DA_EXAMRECORD                 TABLE        12,746,041        99.89

引起 Global Cache Buffer Busy 的确实是 表        DA_EXAMRECORD        


建议 调优 语句：
DELETE FROM DA_EXAMRECORD WHERE RESULT_ID=:1 AND QUESTION_ID=:2