Oracle辅导：监控SQL语句

会计考友

监控当前数据库谁在运行什么SQL语句 　　SELECT osuser, username, sql_text from v$session a, v$sqltext b
　　where a.sql_address =b.address order by address, piece;
# X6 q5 r- e, z# k) @  L　　分析表
$ b9 N% F* i8 _: p　　analyze table tablename compute statistics for all indexes;
6 \6 }* d- L& A: u  O+ h% T( F. H  u　　analyze table tablename compute statistics for all indexed columns;
  g8 y3 F- P1 O+ S5 s* ?　　analyze table tablename compute statistics for table;
　　监控事例的等待
' \# d0 \( J+ B　　select event,sum(decode(wait_Time,0,0,1)) "Prev",
" ^5 D- O; z% `- B" V4 B$ j) T　　sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
　　from v$session_Wait
　　group by event order by 4;
　　查看碎片程度高的表
　　SELECT segment_name table_name , COUNT(*) extents
　　FROM dba_segments WHERE owner NOT IN (SYS, SYSTEM) GROUP BY segment_name
　　HAVING COUNT(*) = (SELECT MAX( COUNT(*) FROM dba_segments GROUP BY segment_name);
9 B+ ]/ M3 \* }# o  V　　表、索引的存储情况检查
0 D# ?, s4 e& G: h  ?7 X　　select segment_name,sum(bytes),count(*) ext_quan from dba_extents where
* H$ h/ b# O% {5 T" g/ F* D　　tablespace_name=&tablespace_name and segment_type=TABLE group by tablespace_name,segment_name;
　　select segment_name,count(*) from dba_extents where segment_type=INDEX and owner=&owner
) ~- t" K: S8 j) J# P　　group by segment_name;
: ]3 h% s2 t9 a1 K1 X" k　　找使用CPU多的用户session
' Z$ u2 X: i  q. {! [0 ~8 ]　　12是cpu used by this session
　　select a.sid,spid,status,substr(a.program,1,40) prog,a.terminal,osuser,value/60/100 value
　　from v$session a,v$process b,v$sesstat c
8 b2 x* C. n( a" }* j8 x　　where c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;
　　监控表空间的 I/O 比例
$ q8 S1 V: S) ?# y+ a+ m; A$ ?/ H+ Y　　select df.tablespace_name name,df.file_name "file",f.phyrds pyr,
8 |3 M  d  n( C4 N　　f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw
　　from v$filestat f, dba_data_files df
　　where f.file# = df.file_id
5 q, n6 ]. S# n4 [4 Q　　order by df.tablespace_name;
　　回滚段的争用情况
　　select name, waits, gets, waits/gets "Ratio"
　　from v$rollstat a, v$rollname b
: [* |. b: j# B9 D" Q, R　　where a.usn = b.usn;
　　在某个用户下找所有的索引
　　select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
　　from user_ind_columns, user_indexes
/ b+ Z  P( P0 f9 \; y3 }　　where user_ind_columns.index_name = user_indexes.index_name
　　and user_ind_columns.table_name = user_indexes.table_name
5 c8 l" T2 a# J3 c3 u　　order by user_indexes.table_type, user_indexes.table_name,
! A8 `5 P; u: {2 I% n5 p/ H　　user_indexes.index_name, column_position;
5 k4 }' Q/ V! u6 Q* z　　监控文件系统的 I/O 比例
　　select substr(a.file#,1,2) "#", substr(a.name,1,30) "Name",
　　a.status, a.bytes, b.phyrds, b.phywrts
　　from v$datafile a, v$filestat b
% m. k: T1 `; x' B0 S2 {
% b0 @3 s: I9 g0 [: u% l　　where a.file# = b.file#;

会计考友

</p>　　监控 SGA 中字典缓冲区的命中率
8 X% k, v: R" c7 T3 i　　select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio",
$ D  o& Z! ~2 y& Z　　(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"
　　from v$rowcache
! e/ }! P- H  D　　where gets+getmisses 0
　　group by parameter, gets, getmisses;
　　监控 SGA 中共享缓存区的命中率，应该小于1％
　　select sum(pins) "Total Pins", sum(reloads) "Total Reloads",
　　sum(reloads)/sum(pins) *100 libcache
　　from v$librarycache;
* \( J' F/ n) m7 ?" r+ q　　select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"
" r3 ?5 K5 z% l" V! W3 n) W　　from v$librarycache;
* [0 u4 ?% H/ t　　监控 SGA 的命中率
+ ^9 Z. V! e4 x' h" {$ _* [　　select a.value + b.value "logical_reads", c.value "phys_reads",
- t( f! d* X4 }# g& }( I3 p　　round(100 * ((a.value+b.value)-c.value) / (a.value+b.value)) "BUFFER HIT RATIO"
　　from v$sysstat a, v$sysstat b, v$sysstat c
　　where a.statistic# = 38 and b.statistic# = 39
　　and c.statistic# = 40;
　　监控 SGA 中重做日志缓存区的命中率，应该小于1％
　　SELECT name, gets, misses, immediate_gets, immediate_misses,
　　Decode(gets,0,0,misses/gets*100) ratio1,
　　Decode(immediate_gets+immediate_misses,0,0,
2 s  ~6 `/ K; ]9 z- F　　immediate_misses/(immediate_gets+immediate_misses)*100) ratio2
0 W8 Q4 b3 P8 H5 A5 ]) s1 c　　FROM v$latch WHERE name IN (redo allocation, redo copy);
　　显示所有数据库对象的类别和大小
2 {2 B+ G6 m# p7 P) _　　select count(name) num_instances ,type ,sum(source_size) source_size ,
　　sum(parsed_size) parsed_size ,sum(code_size) code_size ,sum(error_size) error_size,
　　sum(source_size) +sum(parsed_size) +sum(code_size) +sum(error_size) size_required
, N. R5 v1 L" x7 m& O　　from dba_object_size
- M( L) k; y7 @% F8 _8 K2 S3 L　　group by type order by 2;
) y% |9 U0 p( n; [) }: X# d; a　　监控内存和硬盘的排序比率，最好使它小于 .10，增加 sort_area_size
　　SELECT name, value FROM v$sysstat WHERE name IN (sorts (memory), sorts (disk));
* v$ Z5 S; _/ C/ q3 t, q　　监控字典缓冲区
　　SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE;
　　SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE;
* M8 R% r& p: P1 A) N9 w- A1 [& B　　SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM V$LIBRARYCACHE;
　　后者除以前者,此比率小于1％,接近0％为好。
　　SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"
  [5 S% H8 p# d% x% m　　FROM V$ROWCACHE
　　监控 MTS
　　select busy/(busy+idle) "shared servers busy" from v$dispatcher;
　　此值大于0.5时，参数需加大
4 ^3 @3 K1 f# e7 F% e% S　　select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where type=dispatcher;
" G- i; u" [, h/ F　　select count(*) from v$dispatcher;
0 F3 h7 t& I3 l8 G- a, O8 W, A　　select servers_highwater from v$mts;
　　servers_highwater接近mts_max_servers时，参数需加大
　　碎片程度
$ I+ p, e) ^  C1 t　　select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name
　　having count(tablespace_name)>10;
9 W1 `. D/ k8 k: ~2 p　　alter tablespace name coalesce;
$ L/ ^( H9 l/ C　　alter table name deallocate unused;
! t. k+ b6 D8 x  J　　create or replace view ts_blocks_v as
! Q/ X9 l1 Q+ f0 T% m0 t　　select tablespace_name,block_id,bytes,blocks,free space segment_name from dba_free_space
　　union all
　　select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents;
　　select * from ts_blocks_v;
　　select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space
  e# [, e4 i6 `: ]& q( ?　　group by tablespace_name;