oracle性能诊断排查

https://blog.csdn.net/qq_30553235/article/details/78809872

查看oracle用户权限：

1.查看不同用户的连接数
select username,count(username) from v$session where username is not null group by username;
2.查看所有用户
select * from all_users;
3.查看用户或角色系统权限(直接赋值给用户或角色的系统权限)：
select * from dba_sys_privs;
select * from user_sys_privs;
4.查看角色(只能查看登陆用户拥有的角色)所包含的权限
select * from role_sys_privs;
5.查看用户对象权限：
select * from dba_tab_privs;
select * from all_tab_privs;
select * from user_tab_privs;

6.查看所有角色：
select * from dba_roles;
7.查看用户或角色所拥有的角色：
select * from dba_role_privs;
select * from user_role_privs;
8.查看哪些用户有sysdba或sysoper系统权限(查询时需要相应权限)
select * from V$PWFILE_USERS;

　　

查看oracle链接池开放及使用

1.查询数据库允许的最大连接数
select value from v$parameter where name = 'processes'
alter system set processes = 300 scope = spfile; //修改链接数<重启数据库>
2.查看当前有哪些用户正在使用数据
select osuser, a.username,cpu_time/executions/1000000||'s', sql_fulltext,machine
from v$session a, v$sqlarea b
where a.sql_address =b.address order by cpu_time/executions desc;

3.查看数据库当前链接数
select count(*) from v$session;
4.查询oracle的并发连接数
select count(*) from v$session where status='ACTIVE';
//show parameter processes #最大连接
//alter system set processes = value scope = spfile;重启数据库 #修改连接

5.查看不同用户的连接数
select username,count(username) from v$session where username is not null group by username;

　　

oracle查看表空间使用率，包含临时表空间

select * from ( 
Select a.tablespace_name, 
to_char(a.bytes/1024/1024,'99,999.999') total_bytes, 
to_char(b.bytes/1024/1024,'99,999.999') free_bytes, 
to_char(a.bytes/1024/1024 - b.bytes/1024/1024,'99,999.999') use_bytes, 
to_char((1 - b.bytes/a.bytes)*100,'99.99') || '%' use 
from (select tablespace_name, 
sum(bytes) bytes 
from dba_data_files 
group by tablespace_name) a, 
(select tablespace_name, 
sum(bytes) bytes 
from dba_free_space 
group by tablespace_name) b 
where a.tablespace_name = b.tablespace_name 
union all 
select c.tablespace_name, 
to_char(c.bytes/1024/1024,'99,999.999') total_bytes, 
to_char( (c.bytes-d.bytes_used)/1024/1024,'99,999.999') free_bytes, 
to_char(d.bytes_used/1024/1024,'99,999.999') use_bytes, 
to_char(d.bytes_used*100/c.bytes,'99.99') || '%' use 
from 
(select tablespace_name,sum(bytes) bytes 
from dba_temp_files group by tablespace_name) c, 
(select tablespace_name,sum(bytes_cached) bytes_used 
from v$temp_extent_pool group by tablespace_name) d 
where c.tablespace_name = d.tablespace_name 
) 

　　

oracle查看内存使用情况

SGA、PGA使用情况

--pctused: 使用率
select name,total,round(total-free,2) used, round(free,2) free,round((total-free)/total*100,2) pctused from 
(select 'SGA' name,(select sum(value/1024/1024) from v$sga) total,
(select sum(bytes/1024/1024) from v$sgastat where name='free memory')free from dual)
union
select name,total,round(used,2)used,round(total-used,2)free,round(used/total*100,2)pctused from (
select 'PGA' name,(select value/1024/1024 total from v$pgastat where name='aggregate PGA target parameter')total,
(select value/1024/1024 used from v$pgastat where name='total PGA allocated')used from dual);

内存使用率

-- pctused: 使用率
select * from (
select name,total,round(total-free,2) used, round(free,2) free,round((total-free)/total*100,2) pctused from 
(select 'SGA' name,(select sum(value/1024/1024) from v$sga) total,
(select sum(bytes/1024/1024) from v$sgastat where name='free memory')free from dual)
union
select name,total,round(used,2)used,round(total-used,2)free,round(used/total*100,2)pctused from (
select 'PGA' name,(select value/1024/1024 total from v$pgastat where name='aggregate PGA target parameter')total,
(select value/1024/1024 used from v$pgastat where name='total PGA allocated')used from dual)
  union
select name,round(total,2) total,round((total-free),2) used,round(free,2) free,round((total-free)/total*100,2) pctused from (
select 'Shared pool' name,(select sum(bytes/1024/1024) from v$sgastat where pool='shared pool')total,
(select bytes/1024/1024 from v$sgastat where name='free memory' and pool='shared pool') free from dual)
union
select name,round(total,2)total,round(total-free,2) used,round(free,2) free,round((total-free)/total,2) pctused from (
select 'Default pool' name,( select a.cnum_repl*(select value from v$parameter where name='db_block_size')/1024/1024 total from x$kcbwds a, v$buffer_pool p
  where a.set_id=p.LO_SETID and p.name='DEFAULT' and p.block_size=(select value from v$parameter where name='db_block_size')) total,
(select a.anum_repl*(select value from v$parameter where name='db_block_size')/1024/1024 free from x$kcbwds a, v$buffer_pool p 
where a.set_id=p.LO_SETID and p.name='DEFAULT' and p.block_size=(select value from v$parameter where name='db_block_size')) free from dual)
union
  select name,nvl(round(total,2),0)total,nvl(round(total-free,2),0) used,nvl(round(free,2),0) free,nvl(round((total-free)/total,2),0) pctused from (
select 'KEEP pool' name,(select a.cnum_repl*(select value from v$parameter where name='db_block_size')/1024/1024 total from x$kcbwds a, v$buffer_pool p
  where a.set_id=p.LO_SETID and p.name='KEEP' and p.block_size=(select value from v$parameter where name='db_block_size')) total,
(select a.anum_repl*(select value from v$parameter where name='db_block_size')/1024/1024 free from x$kcbwds a, v$buffer_pool p 
where a.set_id=p.LO_SETID and p.name='KEEP' and p.block_size=(select value from v$parameter where name='db_block_size')) free from dual)
union
select name,nvl(round(total,2),0)total,nvl(round(total-free,2),0) used,nvl(round(free,2),0) free,nvl(round((total-free)/total,2),0) pctused from (
select 'RECYCLE pool' name,( select a.cnum_repl*(select value from v$parameter where name='db_block_size')/1024/1024 total from x$kcbwds a, v$buffer_pool p
  where a.set_id=p.LO_SETID and p.name='RECYCLE' and p.block_size=(select value from v$parameter where name='db_block_size')) total,
(select a.anum_repl*(select value from v$parameter where name='db_block_size')/1024/1024 free from x$kcbwds a, v$buffer_pool p 
where a.set_id=p.LO_SETID and p.name='RECYCLE' and p.block_size=(select value from v$parameter where name='db_block_size')) free from dual)
union
select name,nvl(round(total,2),0)total,nvl(round(total-free,2),0) used,nvl(round(free,2),0) free,nvl(round((total-free)/total,2),0) pctused from(
select 'DEFAULT 16K buffer cache' name,(select a.cnum_repl*16/1024 total from x$kcbwds a, v$buffer_pool p
  where a.set_id=p.LO_SETID and p.name='DEFAULT' and p.block_size=16384) total,
  (select a.anum_repl*16/1024 free from x$kcbwds a, v$buffer_pool p 
where a.set_id=p.LO_SETID and p.name='DEFAULT' and p.block_size=16384) free from dual)
union
select name,nvl(round(total,2),0)total,nvl(round(total-free,2),0) used,nvl(round(free,2),0) free,nvl(round((total-free)/total,2),0) pctused from(
select 'DEFAULT 32K buffer cache' name,(select a.cnum_repl*32/1024 total from x$kcbwds a, v$buffer_pool p
  where a.set_id=p.LO_SETID and p.name='DEFAULT' and p.block_size=32768) total,
  (select a.anum_repl*32/1024 free from x$kcbwds a, v$buffer_pool p 
where a.set_id=p.LO_SETID and p.name='DEFAULT' and p.block_size=32768) free from dual)
union
select name,total,total-free used,free, (total-free)/total*100 pctused from (
select 'Java Pool' name,(select sum(bytes/1024/1024) total from v$sgastat where pool='java pool' group by pool)total,
( select bytes/1024/1024 free from v$sgastat where pool='java pool' and name='free memory')free from dual)
union
select name,Round(total,2),round(total-free,2) used,round(free,2) free, round((total-free)/total*100,2) pctused from (
select 'Large Pool' name,(select sum(bytes/1024/1024) total from v$sgastat where pool='large pool' group by pool)total,
( select bytes/1024/1024 free from v$sgastat where pool='large pool' and name='free memory')free from dual)
order by pctused desc);

　　

诊断

select * from v$sga_dynamic_components;
select * from v$pgastat;
 
-- 查询share pool的空闲内存
select a.*,round(a.bytes/1024/1024,2) M from v$sgastat a where a.NAME = 'free memory';
 
-- 通过下面的sql查询占用share pool内存大于10M的sql
SELECT substr(sql_text,1,100) "Stmt", count(*),
                sum(sharable_mem)    "Mem",
                sum(users_opening)   "Open",
                sum(executions)      "Exec"
          FROM v$sql
         GROUP BY substr(sql_text,1,100)
        HAVING sum(sharable_mem) > 10000000;
        
        
-- 查询一下version count过高的语句
SELECT address,
       sql_id,
       hash_value,
       version_count,
       users_opening,
       users_executing,
       sql_text
  FROM v$sqlarea WHERE version_count > 10;