普通用户获取详细执行计划需要哪些权限

普通用户获取详细执行计划需要哪些权限

 

       近日换了工作，上来第一天就要求优化sql，众所周知，sql优化最重要的就是执行计划，然后开发人员因为权限限制，时常无法获取最为详细的执行计划，那么获取这些详细信息需要哪些权限呢？

       1.实验环境

       SQL>show user

USER is "SYS"

 

SQL> set linesize 1000;

SQL> select version from v$instance;

 

VERSION

-----------------

11.2.0.1.0

--创建用户

SQL> create user tempuser identified by tempuser;

 

User created.

--授予必要的权限

SQL> grant resource to tempuser;

 

Grant succeeded.

 

SQL> grant connect to tempuser;

 

Grant succeeded.

 

2.tempuser用户调试执行计划

SQL> show user

USER is "TEMPUSER"

SQL> create table test(id int);

 

Table created.

 

SQL> select count(1) from test;

 

  COUNT(1)

----------

         0

 

SQL> select * from table(dbms_xplan.display_cursor);

 

PLAN_TABLE_OUTPUT

-----------------------------------------------------------

User has no SELECT privilege on V$SESSION

 

--这里我们看到提示需要对V$SESSION的select
权限

--赋权

SQL> grant select on v_$session to tempuser;

 

Grant succeeded.

--这里注意对象是 v_$session
而不是我们经常使用的 v$session
因为v$session是v_$session的同义词

 

--再调试

SQL> select count(1) from test;

 

  COUNT(1)

----------

         0

 

SQL> select * from table(dbms_xplan.display_cursor);

 

PLAN_TABLE_OUTPUT

--------------------------------------------------------------------------------

User has no SELECT privilege on V$SQL_PLAN

 

--这里看到提示变了,继续赋权

SQL> grant select on v_$sql_plan to tempuser;

 

Grant succeeded.

 

SQL> select count(1) from test;

 

  COUNT(1)

----------

         0

 

SQL> select * from table(dbms_xplan.display_cursor);

 

PLAN_TABLE_OUTPUT

--------------------------------------------------------------------------------

User has no SELECT privilege on V$SQL_PLAN

 

--然而这里我们看到的提示没变，我们明明已经赋予权限了呀？

SQL> show user;

USER is "TEMPUSER"

SQL> select count(1) from v$sql_plan;

 

  COUNT(1)

----------

      4060

 

--我们看到权限已经赋予，但提示却还是一样，我百度了一些资料，得到答案，这里还需要v$sql的权限，至于为什么，我没有找到相关文档，也许可以这样理解，如果我们平常需要查询一句sql的执行计划，首先需要该sql的sql
id，而这个sqlid
一般我们都是需要去v$sql
里去查询的，而oracle内部的算法，不外乎也是这种思路吧。

--继续赋权

SQL> grant select on v_$sql to tempuser;

 

Grant succeeded.

 

SQL> select count(1) from test;

 

  COUNT(1)

----------

         0

 

SQL> select * from table(dbms_xplan.display_cursor);

 

PLAN_TABLE_OUTPUT

--------------------------------------------------------------------------------

SQL_ID  7zrgxh35ctntg, childnumber 1

-------------------------------------

select count(1) from test

 

Plan hash value: 1950795681

 

-------------------------------------------------------------------

| Id  | Operation          | Name | Rows  | Cost (%CPU)| Time     |

-------------------------------------------------------------------

|   0 | SELECT STATEMENT   |     |       |     2 (100)|          |

|   1 |  SORT AGGREGATE    |     |     1 |            |          |

|   2 |   TABLE ACCESS FULL| TEST |     1 |    2   (0)| 00:00:01 |

-------------------------------------------------------------------

 

Note

-----

   - dynamic sampling used forthis statement (level=2)

 

18 rows selected.

 

--ok,这边已经有执行计划了，继续详细信息

SQL> select * fromtable(dbms_xplan.display_cursor(null,null,'ADVANCED  ALLSTATS LAST PEEKED_BINDS'));

 

PLAN_TABLE_OUTPUT

--------------------------------------------------------------------------------

User has no SELECT privilege on V$SQL_PLAN_STATISTICS_ALL

 

--继续吧

SQL> grant select on v_$sql_plan_statistics_all to tempuser;

 

Grant succeeded.

 

--这里statistics_level =all让统计信息最为详尽

SQL> alter session set statistics_level =all;

 

Session altered.

SQL> select count(1) from test;

 

  COUNT(1)

----------

         0

 

SQL> select * fromtable(dbms_xplan.display_cursor(null,null,'ADVANCED  ALLSTATS LAST PEEKED_BINDS'));

 

PLAN_TABLE_OUTPUT

--------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------

SQL_ID  7zrgxh35ctntg, childnumber 2

-------------------------------------

select count(1) from test

 

Plan hash value: 1950795681

 

---------------------------------------------------------------------------------------------------

| Id  | Operation          | Name | Starts | E-Rows | Cost(%CPU)| E-Time   | A-Rows |   A-Time  |

---------------------------------------------------------------------------------------------------

|   0 | SELECT STATEMENT   |     |      1 |        |    2 (100)|          |      1 |00:00:00.01 |

|   1 |  SORT AGGREGATE    |     |      1 |      1 |            |          |     1 |00:00:00.01 |

|   2 |   TABLE ACCESS FULL| TEST |      1 |     1 |     2   (0)| 00:00:01 |      0 |00:00:00.01 |

---------------------------------------------------------------------------------------------------

 

Query Block Name / Object Alias (identified by operation id):

-------------------------------------------------------------

 

   1 - SEL$1

   2 - SEL$1 / TEST@SEL$1

 

Outline Data

-------------

 

  /*+

      BEGIN_OUTLINE_DATA

     IGNORE_OPTIM_EMBEDDED_HINTS

     OPTIMIZER_FEATURES_ENABLE('11.2.0.1')

      DB_VERSION('11.2.0.1')

      ALL_ROWS

     OUTLINE_LEAF(@"SEL$1")

      FULL(@"SEL$1""TEST"@"SEL$1")

      END_OUTLINE_DATA

  */

 

Column Projection Information (identified by operation id):

-----------------------------------------------------------

 

   1 - (#keys=0) COUNT(*)[22]

 

Note

-----

   - dynamic sampling used forthis statement (level=2)

 

 

43 rows selected.

b803
 

--ok，已经非常详细了，但好像缺了点什么，数据块的读取，没有显示，换个工具autotrace

SQL> set autotrace on;

SP2-0618: Cannot find the Session Identifier.  Check PLUSTRACE role is enabled

SP2-0611: Error enabling STATISTICS report

--显示需要一个角色名叫做 PLUSTRACE

--查询官方文档 PLUSTRACE是需要自己创建的一个角色，代码在@$ORACLE_HOME/sqlplus/admin/plustrce.sql

--代码如下

[oracle@panyc admin]$ cat $ORACLE_HOME/sqlplus/admin/plustrce.sql

--

-- Copyright (c) Oracle Corporation 1995, 2002.  All Rights Reserved.

--

-- NAME

--   plustrce.sql

--

-- DESCRIPTION

--   Creates a role with accessto Dynamic Performance Tables

--   for the SQL*Plus SETAUTOTRACE ... STATISTICS command.

--   After this script hasbeen run, each user requiring access to

--   the AUTOTRACE featureshould be granted the PLUSTRACE role by

--   the DBA.

--

-- USAGE

--   sqlplus"sys/knl_test7 as sysdba" @plustrce

--

--   Catalog.sql must havebeen run before this file is run.

--   This file must be runwhile connected to a DBA schema.

 

set echo on

 

drop role plustrace;

create role plustrace;

 

grant select on v_$sesstat to plustrace;

grant select on v_$statname to plustrace;

grant select on v_$mystat to plustrace;

grant plustrace to dba with admin option;

 

set echo off

 

--从代码上看出，还需要三张表的权限

SQL> grant select on v_$sesstat to tempuser;

 

Grant succeeded.

 

SQL> grant select on v_$statname to tempuser;

 

Grant succeeded.

 

SQL> grant select on v_$mystat to tempuser;

 

Grant succeeded.

 

--这个时候就不报错了。

       SQL>set autotrace on;

SQL>

SQL> select count(1) from test;

 

  COUNT(1)

----------

         0

 

 

Execution Plan

----------------------------------------------------------

Plan hash value: 1950795681

 

-------------------------------------------------------------------

| Id  | Operation          | Name | Rows  | Cost (%CPU)| Time     |

-------------------------------------------------------------------

|   0 | SELECT STATEMENT   |     |     1 |     2  (0)| 00:00:01 |

|   1 |  SORT AGGREGATE    |     |     1 |            |          |

|   2 |   TABLE ACCESS FULL| TEST |     1 |    2   (0)| 00:00:01 |

-------------------------------------------------------------------

 

Note

-----

   - dynamic sampling used forthis statement (level=2)

 

 

Statistics

----------------------------------------------------------

         0  recursive calls

         0  db block gets

         0  consistent gets

         0  physical reads

         0  redo size

       345  bytes sent via SQL*Net toclient

       364  bytes received via SQL*Netfrom client

         2  SQL*Net roundtrips to/fromclient

         0  sorts (memory)

         0  sorts (disk)

          1 rows processed

 

--注意：红色部分是只有autotrace显示的。

 

3.结论

       使用dbms_xplan.display_cursor(基于内部视图)

       必要的表：V_$SESSION，V_$SQL_PLAN，V_$SQL

高级统计：V_$SQL_PLAN_STATISTICS_ALL

其他环境变量：statistics_level =all 或者 hints

 

使用autotrace(基于plan_table)

必要的表:plan_table

高级统计: v_$sesstat,v_$statname,v_$mystat