[Oracle] - 性能优化工具（5） - AWRSQL

在AWR中定位到问题SQL语句后想要了解该SQL statement的具体执行计划，于是就用AWR报告中得到的SQL ID去V$SQL等几个动态性能视图中查询，但发现V$SQL或V$SQL_PLAN视图都已经找不到对应SQL ID的记录，一般来说这些语句已经从shared pool共享池中被替换出去了。
这个时候我们可以尝试使用DBMS_XPLAN.DISPLAY_AWR存储过程来将Oracle Automatic Workload Repository自动负载仓库中记录的SQL语句相关信息抽取出来，如:

@?/rdbms/admin/awrsqrpt.sql

下面是上诉语句生成的AWRSQL：

WORKLOAD REPOSITORY SQL Report

Snapshot Period Summary

DB Name	DB Id	Instance	Inst num	Startup Time	Release	RAC
TEST11G	977587123	test11g	1	23-2月 -14 07:02	11.2.0.1.0	NO

	Snap Id	Snap Time	Sessions	Cursors/Session
Begin Snap:	2039	23-2月 -14 15:56:23	28	2.0
End Snap:	2040	23-2月 -14 15:56:38	30	1.9
Elapsed:		0.24 (mins)
DB Time:		0.25 (mins)

SQL Summary

SQL Id	Elapsed Time (ms)	Module	Action	SQL Text
1rrtf60fmhxkj	13,564	SQL*Plus		SELECT COUNT(*) FROM T1, T2 WHERE T1.OBJECT_ID=T2.OBJECT_ID...

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SQL ID: 1rrtf60fmhxkj

• 1st Capture and Last Capture Snap IDs refer to Snapshot IDs witin the snapshot range
• SELECT COUNT(*) FROM T1,T2 WHERE T1.OBJECT_ID=T2.OBJECT_ID

#	Plan Hash Value	Total Elapsed Time(ms)	Executions	1st Capture Snap ID	Last Capture Snap ID
1	4274056747	13,564	1,000	2040	2040

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Plan 1(PHV: 4274056747)

• Plan Statistics
• Execution Plan

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Plan Statistics

• % Total DB Time is the Elapsed Time of the SQL statement divided into the Total Database Time multiplied by 100

Stat Name	Statement Total	Per Execution	% Snap Total
Elapsed Time (ms)	13,564	13.56	92.27
CPU Time (ms)	13,385	13.38	91.76
Executions	1,000
Buffer Gets	1,051,075	1,051.08	99.48
Disk Reads	1,044	1.04	99.90
Parse Calls	1	0.00	0.36
Rows	1,000	1.00
User I/O Wait Time (ms)	55
Cluster Wait Time (ms)	0
Application Wait Time (ms)	0
Concurrency Wait Time (ms)	0
Invalidations	0
Version Count	1
Sharable Mem(KB)	14

Back to Plan 1(PHV: 4274056747) 
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Execution Plan

Id	Operation	Name	Rows	Bytes	Cost (%CPU)	Time
0	SELECT STATEMENT				296 (100)
1	SORT AGGREGATE		1	26
2	HASH JOIN		100	2600	296 (1)	00:00:04
3	TABLE ACCESS FULL	T2	100	1300	3 (0)	00:00:01
4	TABLE ACCESS FULL	T1	69217	878K	292 (1)	00:00:04

• dynamic sampling used for this statement (level=2)

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Full SQL Text

SQL Id	SQL Text
1rrtf60fmhxkj	SELECT COUNT(*) FROM T1, T2 WHERE T1.OBJECT_ID=T2.OBJECT_ID