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性能监控之监控SQL语句
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分析表
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analyze
TABLE tablename compute statistics
FOR
ALL indexes;
-
analyze
TABLE tablename compute statistics
FOR
ALL indexed
COLUMNS;
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analyze
TABLE tablename compute statistics
FOR
TABLE;
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监控事例的等待
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SELECT event
,sum
(decode
(wait_Time
,0
,0
,
1
)
)
"Prev"
,
-
sum
(decode
(wait_Time
,0
,
1
,0
)
)
"Curr"
,count
(
*
)
"Tot"
-
FROM v$session_Wait
-
GROUP
BY event
ORDER
BY
4;
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-
查看碎片程度高的表
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-
SELECT segment_name table_name
, COUNT
(
*
) extents
-
FROM dba_segments
WHERE owner
NOT
IN
(SYS
, SYSTEM
)
GROUP
BY segment_name
-
HAVING COUNT
(
*
)
=
(
SELECT MAX
( COUNT
(
*
)
FROM dba_segments
GROUP
BY segment_name
);
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表、索引的存储情况检查
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SELECT segment_name
,sum
(bytes
)
,count
(
*
) ext_quan
FROM dba_extents
WHERE
-
tablespace_name
=&tablespace_name
AND segment_type
=
TABLE
GROUP
BY tablespace_name
,segment_name;
-
-
SELECT segment_name
,count
(
*
)
FROM dba_extents
WHERE segment_type
=
INDEX
AND owner
=&owner
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GROUP
BY segment_name;
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找使用CPU多的用户session
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-
12是cpu used
BY this session
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SELECT a
.sid
,spid
,
STATUS
,substr
(a
.program
,
1
,
40
) prog
,a
.terminal
,osuser
,value
/
60
/
100 value
-
FROM v$session a
,v$process b
,v$sesstat c
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WHERE c
.statistic
#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;
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监控表空间的 I
/O 比例
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-
SELECT df
.tablespace_name name
,df
.file_name
"file"
,f
.phyrds pyr
,
-
f
.phyblkrd pbr
,f
.phywrts pyw
, f
.phyblkwrt pbw
-
FROM v$filestat f
, dba_data_files df
-
WHERE f
.file
# = df.file_id
-
ORDER
BY df
.tablespace_name;
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回滚段的争用情况
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SELECT name
, waits
, gets
, waits
/gets
"Ratio"
-
FROM v$rollstat a
, v$rollname b
-
WHERE a
.usn
= b
.usn;
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在某个用户下找所有的索引
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SELECT user_indexes
.table_name
, user_indexes
.index_name
,uniqueness
, column_name
-
FROM user_ind_columns
, user_indexes
-
WHERE user_ind_columns
.index_name
= user_indexes
.index_name
-
AND user_ind_columns
.table_name
= user_indexes
.table_name
-
ORDER
BY user_indexes
.table_type
, user_indexes
.table_name
,
-
user_indexes
.index_name
, column_position;
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监控文件系统的 I
/O 比例
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SELECT substr
(a
.file
#,1,2) "#", substr(a.name,1,30) "Name",
-
a
.
STATUS
, a
.bytes
, b
.phyrds
, b
.phywrts
-
FROM v$datafile a
, v$filestat b
-
WHERE a
.file
# = b.file#;
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监控 SGA 中字典缓冲区的命中率
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-
SELECT parameter
, gets
,Getmisses
, getmisses
/
(gets
+getmisses
)
*
100
"miss ratio"
,
-
(
1
-
(sum
(getmisses
)
/
(sum
(gets
)
+sum
(getmisses
)
)
)
)
*
100
"Hit ratio"
-
FROM v$rowcache
-
WHERE gets
+getmisses
<>0
-
GROUP
BY parameter
, gets
, getmisses;
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-
监控 SGA 中共享缓存区的命中率，应该小于
1％
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SELECT sum
(pins
)
"Total Pins"
, sum
(reloads
)
"Total Reloads"
,
-
sum
(reloads
)
/sum
(pins
)
*
100 libcache
-
FROM v$librarycache;
-
-
SELECT sum
(pinhits
-reloads
)
/sum
(pins
)
"hit radio"
,sum
(reloads
)
/sum
(pins
)
"reload percent"
-
FROM v$librarycache;
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监控 SGA 的命中率
-
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SELECT a
.value
+ b
.value
"logical_reads"
, c
.value
"phys_reads"
,
-
round
(
100
*
(
(a
.value
+b
.value
)
-c
.value
)
/
(a
.value
+b
.value
)
)
"BUFFER HIT RATIO"
-
FROM v$sysstat a
, v$sysstat b
, v$sysstat c
-
WHERE a
.statistic
# = 38 and b.statistic# = 39
-
AND c
.statistic
# = 40;
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监控 SGA 中重做日志缓存区的命中率，应该小于
1％
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SELECT name
, gets
, misses
, immediate_gets
, immediate_misses
,
-
Decode
(gets
,0
,0
,misses
/gets
*
100
) ratio1
,
-
Decode
(immediate_gets
+immediate_misses
,0
,0
,
-
immediate_misses
/
(immediate_gets
+immediate_misses
)
*
100
) ratio2
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FROM v$latch
WHERE name
IN
(redo allocation
, redo copy
);
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显示所有数据库对象的类别和大小
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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
-
FROM dba_object_size
-
GROUP
BY type
ORDER
BY
2;
-
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监控内存和硬盘的排序比率，最好使它小于
.10，增加 sort_area_size
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SELECT name
, value
FROM v$sysstat
WHERE name
IN
(sorts
(memory
)
, sorts
(disk
)
);
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监控当前数据库谁在运行什么SQL语句
-
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SELECT osuser
, username
, sql_text
FROM v$session a
, v$sqltext b
-
WHERE a
.sql_address
=b
.address
ORDER
BY address
, piece;
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监控字典缓冲区
-
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SELECT
(SUM
(PINS
- RELOADS
)
)
/ SUM
(PINS
)
"LIB CACHE"
FROM V$LIBRARYCACHE;
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SELECT
(SUM
(GETS
- GETMISSES
- USAGE
- FIXED
)
)
/ SUM
(GETS
)
"ROW CACHE"
FROM V$ROWCACHE;
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SELECT SUM
(PINS
)
"EXECUTIONS"
, SUM
(RELOADS
)
"CACHE MISSES WHILE EXECUTING"
FROM V$LIBRARYCACHE;
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后者除以前者
,此比率小于
1％
,接近0％为好。
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SELECT SUM
(GETS
)
"DICTIONARY GETS"
,SUM
(GETMISSES
)
"DICTIONARY CACHE GET MISSES"
-
FROM V$ROWCACHE
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监控 MTS
-
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SELECT busy
/
(busy
+idle
)
"shared servers busy"
FROM v$dispatcher;
-
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此值大于
0.5时，参数需加大
-
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SELECT sum
(wait
)
/sum
(totalq
)
"dispatcher waits"
FROM v$queue
WHERE type
=dispatcher;
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SELECT count
(
*
)
FROM v$dispatcher;
-
SELECT servers_highwater
FROM v$mts;
-
-
servers_highwater接近mts_max_servers时，参数需加大
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碎片程度
-
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SELECT tablespace_name
,count
(tablespace_name
)
FROM dba_free_space
GROUP
BY tablespace_name
-
HAVING count
(tablespace_name
)
>
10;
-
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ALTER tablespace name coalesce;
-
ALTER
TABLE name deallocate unused;
-
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CREATE
OR
REPLACE
VIEW ts_blocks_v
AS
-
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;
-
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SELECT tablespace_name
,sum
(bytes
)
,max
(bytes
)
,count
(block_id
)
FROM dba_free_space
-
GROUP
BY tablespace_name;
