经常使用的Oracle监控语句
最近项目需要，性能、数据准确性等问题一个接一个解决，很累，但我是很看好这种机遇。
客户有时会说服务器CPU占用100%，妈啊，小型机啊，为了要证明是程序问题还是SQL语句的问题，或者是程序死锁问题，通过各种方式进行检查，发现有一个明细表的查询出问题了，真是大快人心!于是把一些在监控过程中学到的知识记录下来，做个标记，日后有用啊，现在的DBA身价不菲。
--根据FILE_ID & BLOCK_ID获得对象名称
SELECT /*+ RULE*/ owner, segment_name, segment_type
FROM dba_extents
WHERE file_id = &file_id
AND &block_id BETWEEN block_id AND block_id + blocks - 1;
--根据操作系统PID,查询SESSION信息
SELECT a.sid, a.serial#, b.spid, a.terminal, a.machine, a.program, a.osuser
FROM v$session a, v$process b
WHERE a.paddr = b.addr AND b.spid = '&SPID';
--根据SESSION SID,查询操作系统PID
SELECT a.sid, a.serial#, b.spid, a.terminal, a.machine, a.program, a.osuser
FROM v$session a, v$process b
WHERE a.paddr = b.addr AND a.sid = '&SID';
--查询用户正在执行的SQL
SELECT sql_text
FROM v$sqltext
WHERE hash_value = (SELECT sql_hash_value
FROM v$session
WHERE sid = &sid)
ORDER BY piece;
--查询当前的系统等待事件
SELECT *
FROM v$session_wait
WHERE event NOT LIKE '%SQL*Net%'
AND event NOT LIKE '%rdbms%'
AND event NOT LIKE '%timer%'
AND event NOT LIKE '%jobq%'
ORDER BY event, seconds_in_wait;
--查询详细的当前系统等待事件
SELECT s.sid, s.username, w.seq#, w.event, w.p1text, w.p1, w.p2text, w.p2, w.p3text, w.p3,
w.seconds_in_wait, w.state, s.logon_time, s.osuser, s.program
FROM v$session s, v$session_wait w
WHERE s.sid = w.sid
AND w.event NOT LIKE '%SQL*Net%'
AND w.event NOT LIKE '%rdbms%'
AND w.event NOT LIKE '%timer%'
AND w.event NOT LIKE '%jobq%'
ORDER BY w.event, w.seconds_in_wait;
--查询等待db file sequential/scattered read的Session正在执行的SQL
SELECT s.sid, s.username, t.hash_value, t.piece, t.sql_text
FROM v$session s, v$session_wait w, v$sqltext t
WHERE s.sid = w.sid
AND s.sql_hash_value = t.hash_value
AND w.event IN ('db file sequential read', 'db file scattered read')
ORDER BY s.sid, t.piece;
--查询等待db file sequential/scattered read对应的数据库对象
SELECT /*+ RULE*/ s.sid, s.username, w.seq#, w.event,
d.segment_type, d.owner || '.' || d.segment_name AS segment_name,
w.seconds_in_wait, w.state, s.logon_time
FROM v$session s, v$session_wait w, dba_extents d
WHERE s.sid = w.sid
AND d.file_id = w.p1
AND w.p2 BETWEEN d.block_id AND d.block_id + d.blocks - 1
AND w.event IN ('db file sequential read', 'db file scattered read')
ORDER BY w.event, segment_name;
--查询导致LOCK的SID,SPID,LOCKED_OBJECT,LOCK_TYPE等信息
SELECT /*+ RULE*/
l.sid, p.spid, s.username,s.logon_time, s.osuser, s.program, l.type,
CASE l.TYPE WHEN 'TM' THEN O.object_name WHEN 'TX' THEN '' END as OBJECT_NAME,
DECODE (l.lmode, 0, '0=NONE', 1, '1=NULL', 2, '2=RS', 3, '3=RX', 4, '4=S', 5, '5=SRX', 6, '6=X') lmode,
CASE l.request WHEN 0 THEN '' ELSE 'BLOCKED BY ' || l.id2 END as BLOCKED,
CASE l.block WHEN 0 THEN '' ELSE l.id2 || ' IS BLOCKING' END as BLOCKING,
l.request, l.ctime
FROM v$lock l, v$session s, dba_objects o, v$process p
WHERE l.type in ('TX', 'TM')
AND s.paddr = p.addr
AND l.sid = s.sid
AND l.id1 = o.object_id(+)
ORDER BY s.username, l.sid, l.ctime;
--查询导致DDL LOCK的详细信息
SELECT s.sid, p.spid, s.username, a.owner || '.' || a.NAME AS OBJECT_NAME,
a.TYPE, a.mode_held, a.mode_requested, s.osuser, s.logon_time, s.program
FROM dba_ddl_locks a, v$session s, v$process p
WHERE s.sid = a.session_id
AND s.paddr = p.addr
AND (a.mode_held = 'Exclusive' OR a.mode_requested = 'Exclusive')
ORDER BY s.USERNAME, a.NAME;
--查询事务使用的回滚段
SELECT s.username, s.sid, s.serial#, t.ubafil "UBA filenum",
t.ubablk "UBA Block number", t.used_ublk "Number of undo Blocks Used",
t.start_time, t.status, t.start_scnb, t.xidusn rollid, r.name rollname
FROM v$session s, v$transaction t, v$rollname r
WHERE s.saddr = t.ses_addr AND t.xidusn = r.usn;
####################################################################################################
--查询LIBRARY CACHE PIN等待事件等待的对象
--视图缩写:[K]ernel [G]eneric [L]ibrary Cache Manager [OB]ject
SELECT /*+ RULE*/ addr, kglhdadr, kglhdpar, kglnaobj, kglnahsh, kglhdobj
FROM x$kglob
WHERE kglhdadr IN (SELECT p1raw
FROM v$session_wait
WHERE event LIKE '%library%');
--查询LIBRARY CACHE PIN等待事件中持有被等待对象的SESSION信息
--视图缩写:[K]ernel [G]eneric [L]ibrary Cache Manager Object [P]i[N]s
SELECT /*+ RULE*/ a.SID, a.username, a.program, b.addr, b.kglpnadr, b.kglpnuse,
b.kglpnses, b.kglpnhdl, b.kglpnlck, b.kglpnmod, b.kglpnreq
FROM v$session a, x$kglpn b
WHERE a.saddr = b.kglpnuse
AND b.kglpnmod <> 0
AND b.kglpnhdl IN (SELECT p1raw
FROM v$session_wait
WHERE event LIKE '%library%');
--查询LIBRARY CACHE PIN等待事件中持有被等待对象的SESSION执行的SQL语句
SELECT sql_text
FROM v$sqlarea
WHERE (v$sqlarea.address, v$sqlarea.hash_value) IN (
SELECT sql_address, sql_hash_value
FROM v$session
WHERE SID IN (
SELECT /*+ RULE*/ SID
FROM v$session a, x$kglpn b
WHERE a.saddr = b.kglpnuse
AND b.kglpnmod <> 0
AND b.kglpnhdl IN (SELECT p1raw
FROM v$session_wait
WHERE event LIKE '%library%')));
--查询哪个SESSION正在使用某个对象(LIBRARY CACHE)
SELECT DISTINCT s.sid,
s.username,
s.logon_time,
s.osuser,
s.program,
b.kglnahsh as SQL_HASH_VALUE,
b.kglnaobj as SQL_TEXT
FROM v$session s, x$kglpn n, x$kglob b
WHERE n.kglpnuse = s.saddr
AND upper(b.kglnaobj) LIKE upper('%&OBJECT_NAME%')
AND n.kglpnhdl = b.kglhdadr;
--查询V$SESSION_WAIT用户PIN住了哪些对象(LIBRARY CACHE)
SELECT DISTINCT s.sid,
s.username,
s.logon_time,
s.osuser,
s.program,
n.kglpnmod,
b.kglnahsh AS SQL_HASH_VALUE,
b.kglnaobj AS SQL_TEXT
FROM v$session s, x$kglpn n, x$kglob b
WHERE n.kglpnuse = s.saddr
AND n.kglpnhdl = b.kglhdadr
AND s.sid IN (SELECT sid
FROM v$session_wait
WHERE event NOT LIKE '%SQL*Net%'
AND event NOT LIKE '%rdbms%'
AND event NOT LIKE '%timer%'
AND event NOT LIKE '%jobq%')
ORDER BY s.username;
--查询哪些大对象被载入SHARED POOL时导致其它对象被老化
SELECT s.sid, s.username, s.logon_time, s.osuser, s.program,
k.ksmlrcom, k.ksmlrsiz, k.ksmlrnum, k.ksmlrhon, k.ksmlrses
FROM x$ksmlru k, v$session s
WHERE s.saddr = k.ksmlrses
AND ksmlrsiz > 0;
####################################################################################################
--查询Schema哪些表是全表扫描
SELECT o.name, x.tch
FROM obj$ o, x$bh x, dba_users u
WHERE x.obj = o.dataobj#
AND STANDARD.bitand(x.flag, 524288) > 0
AND u.username = UPPER('&username')
ORDER BY x.tch DESC;
--查询低效率的SQL(BUFFER_GETS排序)
SELECT *
FROM (SELECT s.sid,
b.spid,
s.sql_hash_value,
q.sql_text,
q.executions,
q.buffer_gets,
ROUND(q.buffer_gets / q.executions) AS buffer_per_exec,
ROUND(q.elapsed_time / q.executions) AS cpu_time_per_exec,
q.cpu_time,
q.elapsed_time,
q.disk_reads,
q.rows_processed
FROM v$session s, v$process b, v$sql q
WHERE s.sql_hash_value = q.hash_value
AND s.paddr = b.addr
AND s.status = 'ACTIVE'
AND s.TYPE = 'USER'
AND q.buffer_gets > 0
AND q.executions > 0
ORDER BY buffer_per_exec DESC)
WHERE ROWNUM <= 10;
####################################################################################################
--监控BufferCache命中率
SELECT a.value + b.value logical_reads, c.value phys_reads,
ROUND (100 * (1 - c.value / (a.value + b.value)), 4) hit_ratio
FROM v$sysstat a, v$sysstat b, v$sysstat c
WHERE a.NAME = 'db block gets'
AND b.NAME = 'consistent gets'
AND c.NAME = 'physical reads';
--监控LibraryCache命中率
SELECT SUM (pins) total_pins, SUM (reloads) total_reloads,
SUM (reloads) / SUM (pins) * 100 libcache_reload_ratio
FROM v$librarycache;
--查询产生的跟踪文件名
SELECT p1.VALUE || '/' || p2.VALUE || '_ora_' || p.spid || '.trc' filename
FROM v$process p, v$session s, v$parameter p1, v$parameter p2
WHERE p1.NAME = 'user_dump_dest'
AND p2.NAME = 'db_name'
AND p.addr = s.paddr
AND s.audsid = USERENV ('SESSIONID');
--删除表中的重复记录
DELETE FROM table_name a
WHERE ROWID >
(SELECT MIN (ROWID)
FROM table_name b
WHERE b.pk_column_1 = a.pk_column_1
AND b.pk_column_2 = a.pk_column_2);
