Oracle-绑定执行计划

一、绑定执行计划

Oracle存在某个SQL多个执行计划的情况，那么如何快速将Oracle 好的执行计划，绑定到不好的SQL上呢？

由于版本的演进，绑定执行计划在10g 一般使用sql profile; >=11g之后，大部分使用spm就可以了。

本篇文档针对这两种绑定执行计划的方式进行了梳理。 有需要的小伙伴们可以直接使用。

二、实验测试

2.1 SPM绑定

--好的执行计划，查询SQL ID
SQL> select sql_text ,sql_id from v$sql where sql_text like '%2021_10_19_test_sql_text%';
5yv7w368z62bz
--查询好的执行计划SQL 对应的hash value
select * from table(dbms_xplan.display_awr('&sql',format=>'PEEKED_BINDS'));

select * from table(dbms_xplan.display_cursor('&sql'));

--绑定执行计划
declare
m_clob clob;
begin
select sql_fullteXt
into m_clob
from v$sql
where sql_id = 'bcq5f5sd2k5wu' --需要绑定的SQL ID
and child_number = 0; --需要绑定的SQL ID对应的子游标编号
dbms_output.put_line(m_clob);
dbms_output.put_line(dbms_spm.load_plans_from_cursor_cache(sql_id => '5yv7w368z62bz', --参考需要的执行计划SQL ID  及好的执行计划对应的SQL ID
plan_hash_value => 3270942279, --参考需要的执行计划 Hash value
sql_text => m_clob,
fixed => 'YES',
enabled => 'YES'));

end;
/

--如下实际执行
declare
m_clob clob;
begin
select sql_fullteXt
into m_clob
from v$sql
where sql_id = 'bcq5f5sd2k5wu'
and child_number = 0;
dbms_output.put_line(m_clob);
dbms_output.put_line(dbms_spm.load_plans_from_cursor_cache(sql_id => '5yv7w368z62bz',
plan_hash_value => 3270942279,
sql_text => m_clob,
fixed => 'YES',
enabled => 'YES'));

end;
/

查询是否绑定

select sql_handle, plan_name, accepted, fixed,optimizer_cost from dba_sql_plan_baselines ;

SQL_HANDLE PLAN_NAME ACC FIX OPTIMIZER_COST
------------------------------ ------------------------------ --- --- --------------
SQL_916244ba197a1647 SQL_PLAN_92sk4r8crn5k7f0218608 YES YES 1

删除SPM绑定的执行计划

declare
xx PLS_INTEGER;
BEGIN
xx :=dbms_spm.drop_sql_plan_baseline(sql_handle=>'SQL_916244ba197a1647',plan_name=>null);
END;
/

检查执行计划是否生效，手工可以执行的情况可以看到如下！

exec sql

select * from table(dbms_xplan.display_cursor(null,null,'advanced -PROJECTION -bytes iostats,last'));

- SQL plan baseline SQL_PLAN_92sk4r8crn5k7f0218608 used for this statement

2.2 SQL Profile绑定

使用sql profile绑定执行计划--参考
declare
 ar_profile_hints sys.sqlprof_attr;
 clsql_text CLOB;
begin
select extractvalue(value(d), '/hint') as outline_hints bulk collect
 into ar_profile_hints
 from xmltable('/*/outline_data/hint' passing
 (select xmltype(other_xml) as xmlval
 from dba_hist_sql_plan
 where sql_id = 'SQLID 值'   --好的执行计划对应的SQL ID
 and plan_hash_value = value 值  --好的执行计划对应SQL ID 的hash value值
 and other_xml is not null)) d;
 SELECT sql_text INTO clsql_text
 FROM dba_hist_sqltext
 where sql_id = ' SQLID 值';   --需要绑定的SQL ID的值,通过视图查询该SQL 对应的文本
 DBMS_SQLTUNE.IMPORT_SQL_PROFILE(sql_text => clsql_text,
 profile => ar_profile_hints,
 name => 'PROFILE_ SQLID 值',  --SQL Profile绑定的标记
 force_match => TRUE,——true 表示对于谓词部分 具体值变化后的 SQL_ID 也能使用该 SQL profile
 REPLACE => TRUE);
end;
/

declare
 ar_profile_hints sys.sqlprof_attr;
 clsql_text CLOB;
begin
select extractvalue(value(d), '/hint') as outline_hints bulk collect
 into ar_profile_hints
 from xmltable('/*/outline_data/hint' passing
 (select xmltype(other_xml) as xmlval
 from dba_hist_sql_plan
 where sql_id = '5yv7w368z62bz'
 and plan_hash_value = '3270942279'
 and other_xml is not null)) d;
 SELECT sql_text INTO clsql_text
 FROM dba_hist_sqltext
 where sql_id = 'bcq5f5sd2k5wu';
 DBMS_SQLTUNE.IMPORT_SQL_PROFILE(sql_text => clsql_text,
 profile => ar_profile_hints,
 name => 'PROFILE_ SQLID bcq5f5sd2k5wu',
 force_match => TRUE,
 REPLACE => TRUE);
end;
/
-----------------------------------------好的SQL执行计划，可能并不在历史的视图中记录，可以换成如下在memory cache的视图
select xmltype(other_xml) as xmlval
 from v$sql_plan                       --dba_hist_sql_plan视图找不到记录！
 where sql_id = '5yv7w368z62bz'
 and plan_hash_value = '3270942279'
 and other_xml is not null
--
declare
 ar_profile_hints sys.sqlprof_attr;
 clsql_text CLOB;
begin
select extractvalue(value(d), '/hint') as outline_hints bulk collect
 into ar_profile_hints
 from xmltable('/*/outline_data/hint' passing
 (select xmltype(other_xml) as xmlval
 from v$sql_plan
 where sql_id = '5yv7w368z62bz'
 and plan_hash_value = '3270942279'
 and other_xml is not null)) d;
 SELECT sql_text INTO clsql_text
 FROM dba_hist_sqltext
 where sql_id = 'bcq5f5sd2k5wu';
 DBMS_SQLTUNE.IMPORT_SQL_PROFILE(sql_text => clsql_text,
 profile => ar_profile_hints,
 name => 'PROFILE_ SQLID bcq5f5sd2k5wu',
 force_match => TRUE,
 REPLACE => TRUE);
end;
/

--检查是否绑定成功
SQL> select * from dba_sql_profiles WHERE name ='PROFILE_ SQLID bcq5f5sd2k5wu';
--SQL 能执行的情况下

- SQL profile PROFILE_ SQLID bcq5f5sd2k5wu used for this statement

--删除SQL Profile

BEGIN
DBMS_SQLTUNE.DROP_SQL_PROFILE(name => 'PROFILE_ SQLID bcq5f5sd2k5wu');
END;
/

--验证SQL执行效率对比，可以检查SQL的执行效率

select sql_id,sql_profile，
executions,plan_hash_value,
elapsed_time / DECODE(executions, 0, 1, EXECUTIONS) / 1000 elasp_time_ms,
buffer_gets / DECODE(executions, 0, 1, EXECUTIONS),
disk_reads / DECODE(executions, 0, 1, EXECUTIONS),
cpu_time / DECODE(executions, 0, 1, EXECUTIONS)/1000 cpu_time_ms,
last_load_time,last_active_time,
sql_text,child_number
from v$sql
where SQL_ID IN ('&sql_id');
select *
from (select to_char(begin_interval_time,'yyyy-mm-dd hh24:mi:ss') begin_time,
a.instance_number,
module,
plan_hash_value,
EXECUTIONS_DELTA exec,
decode(EXECUTIONS_DELTA,
0,
buffer_gets_deltA,
round(BUFFER_GETS_DELTA / EXECUTIONS_DELTA)) per_get,
decode(EXECUTIONS_DELTA,
0,
ROWS_PROCESSED_DELTA,
round(ROWS_PROCESSED_DELTA / EXECUTIONS_DELTA, 3))
per_rows,
decode(EXECUTIONS_DELTA,
0,
ELAPSED_TIME_DELTA,
round(ELAPSED_TIME_DELTA / EXECUTIONS_DELTA / 1000,
2)) time_ms,
decode(EXECUTIONS_DELTA,
0,
DISK_READS_DELTA,
round(DISK_READS_DELTA / EXECUTIONS_DELTA, 2)) per_read
from dba_hist_sqlstat a, DBA_HIST_SNAPSHOT b
where a.snap_id = b.snap_id
and a.instance_number = b.instance_number
and a.sql_id = '&sql_id'
order by 1 desc)
where rownum < 100;

SPM非参考，SQL PROFILE ,SQL查询效率部分参考文档https://www.modb.pro/doc/287