为什么oracle10.2.0.5只会获取child#=1的sharedpoollatch
这篇文章主要介绍了为什么oracle 10.2.0.5只会获取child#=1的shared pool latch,具有一定借鉴价值,感兴趣的朋友可以参考下,希望大家阅读完这篇文章之后大有收获,下面让小编带着大家一起了解一下。
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1,可以用oradebug dump heapdump 3转储共享池的结构信息
这个级别一般3即可,6的代价有些大了
2,语法如下:
SQL> oradebug setmypid
Statement processed.
SQL> oradebug dump heapdump 3
Statement processed.
SQL> oradebug tracefile_name
/home/ora10g/admin/ora10g/udump/ora10g_ora_6533.trc
3,转储共享池的TRC文件结构如下:
第一部分:LATCH信息
KGH Latch Directory Information
ldir state: 2 Last allocated slot: 77
Slot [ 1] Latch: 0xa4222c98 Index: 2 Flags: 3 State: 2 next: (nil)
第二部分:HEAP信息,可见共计5个堆,对应子池的个数,由参数_kghdsidx_count控制
HEAP DUMP heap name="sga heap" desc=0x60000058
extent sz=0x47c0 alt=216 het=32767 rec=9 flg=-126 opc=0
parent=(nil) owner=(nil) nex=(nil) xsz=0x160
ds for latch 1: 0x60034fe0 0x60036838 0x60038090 --可见保护其子堆需要3个latch
ds for latch 2: 0x6003e808 0x60040060 0x600418b8
ds for latch 3: 0x60048030 0x60049888 0x6004b0e0
ds for latch 4: 0x60051858 0x600530b0 0x60054908
ds for latch 5: 0x6005b080 0x6005c8d8 0x6005e130 0x6005f988 --保护其子堆需要4个latch
reserved granule count 0 (granule size 16777216)
第三部分:上述每个堆的具体信息,而且TRC下述信息是以每个堆的子堆为基础展开的,其它子堆结构同理
HEAP DUMP heap name="sga heap(1,0)" desc=0x60034fe0
extent sz=0xfe0 alt=216 het=32767 rec=9 flg=-126 opc=0
parent=(nil) owner=(nil) nex=(nil) xsz=0x1000000
latch set 1 of 5
durations enabled for this heap
reserved granules for root 0 (granule size 16777216)
可见子堆由区构成,而区又包括多个CHUNK
第四部分是一个空闲列表的BUCKET列表
FREE LISTS:
Bucket 0 size=32
Bucket 1 size=40
Bucket 2 size=48
Bucket 3 size=56
Bucket 4 size=64
Bucket 5 size=72
Bucket 6 size=80
Bucket 7 size=88
Bucket 8 size=96
Bucket 9 size=104
中间略
Bucket 250 size=12352
Bucket 251 size=12360
Bucket 252 size=16408
Bucket 253 size=32792
Bucket 254 size=65560
也就是说管理空闲空间是由BUCKET进行管理,把可以分配或回收的CHUNK地址信息存储在对应的BUCKET中,具体要存储在哪个BUCKET中,要看CHUNK的大小,和对应的BUCKET进行匹配
第五部分:是一个预备的空间列表BUCKET列表(同第四部分理)
RESERVED FREE LISTS:
Reserved bucket 0 size=32
Reserved bucket 1 size=4400
Reserved bucket 2 size=8216
Reserved bucket 3 size=8696
Reserved bucket 4 size=8704
Reserved bucket 5 size=8712
Reserved bucket 6 size=8720
Reserved bucket 7 size=9368
Reserved bucket 8 size=9376
Reserved bucket 9 size=12352
Reserved bucket 10 size=12360
Reserved bucket 11 size=16408
Reserved bucket 12 size=32792
Reserved bucket 13 size=65560
第六部分:未PIN住的可以重建或重用的chunk列表(lru优先,关于LRU还要研究),如下包括很多CHUNK
UNPINNED RECREATABLE CHUNKS (lru first):
Chunk 0a3bd5420 sz= 56 recreate "fixed allocatio" latch=0x9e5c8db0 --CHUNK地址,大小,状态及类型,CHUNK对应的LATCH地址,经在TRC文件查找,可以和TRC文件第一部分的LATCH关联起来
Chunk 0a3bc7fb8 sz= 56 recreate "fixed allocatio" latch=0x9e5c7d10 --fixed allocatio对应x$ksmsp的ksmchcom,可以理解为CHUNK的名称
中间略
Chunk 0a3ba1a78 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3ba1848 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
SEPARATOR
Chunk 0a3bb2340 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3bb2110 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
中间略
Chunk 0a3b631e0 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3b62fb0 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3b62d80 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3b62b50 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
第七部分:永久或持久的CHUNK列表,同上理,包括很多个CHUNK,不过这里仅一个CHUNK,且其类型为PERM,而且没有LATCH保护
PERMANENT CHUNKS:
Chunk 09e0cd000 sz= 15937536 perm "perm " alo=8424224
Permanent space = 15937536
4,共享池CHUNK的信息可以查询X$KSMSP
SQL> select addr,ksmchidx,ksmchcom,ksmchptr,KSMCHCLS,ksmchsiz,ksmchtyp,ksmchdur from x$ksmsp where ksmchcom='fixed allocatio' and ksmchsiz=56 and KSMCHCLS='recr' and ksmchptr='00000000A3BD5420';
ADDR KSMCHIDX KSMCHCOM KSMCHPTR KSMCHCLS KSMCHSIZ KSMCHTYP KSMCHDUR
---------------- ---------- ---------------- ---------------- -------- ---------- ---------- ----------
00002B0CBA8B5548 1 fixed allocatio 00000000A3BD5420 recr 56 72 2
5,如果HANG SHARED POOL LATCH,oradebug dump heapdump会HANG住
6,暂未在TRC文件找到SHARED POOL LATCH
7,上述TRC文件每个部分后面会列出对应部分可用空间总大小
测试
SQL> select * from v$version where rownum=1;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bi
--转储共享池shared pool
SQL> oradebug setmypid
Statement processed.
SQL> oradebug dump heapdump 3
Statement processed.
SQL> oradebug tracefile_name
/home/ora10g/admin/ora10g/udump/ora10g_ora_6533.trc
--TRC文件
---第一部分是一些latch的信息
KGH Latch Directory Information
ldir state: 2 Last allocated slot: 77
Slot [ 1] Latch: 0xa4222c98 Index: 2 Flags: 3 State: 2 next: (nil)
Slot [ 2] Latch: 0xa4222d78 Index: 3 Flags: 3 State: 2 next: (nil)
Slot [ 3] Latch: 0x6000a6c0 Index: 4 Flags: 3 State: 2 next: (nil)
中间略
Slot [ 75] Latch: 0x600270b0 Index: 1 Flags: 3 State: 2 next: 0x600e85c0
Slot [ 76] Latch: 0x6002abf0 Index: 2 Flags: 3 State: 2 next: (nil)
Slot [ 77] Latch: 0x60031378 Index: 3 Flags: 3 State: 2 next: 0x600e81b8
---第二部是heap的信息,可见共计5个heap堆(注: _kghdsidx_count=5,堆即分配内存的一种内存结构)
HEAP DUMP heap name="sga heap" desc=0x60000058
extent sz=0x47c0 alt=216 het=32767 rec=9 flg=-126 opc=0
parent=(nil) owner=(nil) nex=(nil) xsz=0x160
ds for latch 1: 0x60034fe0 0x60036838 0x60038090 --可见保护其子堆需要3个latch
ds for latch 2: 0x6003e808 0x60040060 0x600418b8
ds for latch 3: 0x60048030 0x60049888 0x6004b0e0
ds for latch 4: 0x60051858 0x600530b0 0x60054908
ds for latch 5: 0x6005b080 0x6005c8d8 0x6005e130 0x6005f988 --保护其子堆需要4个latch
reserved granule count 0 (granule size 16777216)
第三部分是上述每个子堆的具体信息,仅讲述一个子堆即可,其它同理
可知:
1,前4个堆,每个堆有3个子堆
最后一个堆,有4个子堆
2,TRC文件的下面内容是以每个堆的子堆为基础进行,我分析也以此为准
下面详解第三部分,即第一个堆的第一个子堆,即sga heap(1,0),其中1表示第一个堆,0表示第一个子堆
HEAP DUMP heap name="sga heap(1,0)" desc=0x60034fe0
extent sz=0xfe0 alt=216 het=32767 rec=9 flg=-126 opc=0
parent=(nil) owner=(nil) nex=(nil) xsz=0x1000000
latch set 1 of 5
durations enabled for this heap
reserved granules for root 0 (granule size 16777216)
可见子堆下面是一个区extent
EXTENT 0 addr=0x9e000000
可见区extent下面是很多个chunk
Chunk 09e000058 sz= 48 R-freeable "reserved stoppe" --每个chunk包括地址,大小,状态及类型
Chunk 09e000088 sz= 839496 R-free " "
Chunk 09e0ccfd0 sz= 48 R-freeable "reserved stoppe"
Chunk 09e0cd000 sz= 15937536 perm "perm " alo=8424224
Total heap size = 16777128 --这个推大小,就是上面所有chunk的大小之和
可见有一个空闲可用的列表,记录很多个bucket,每个bucket的编号及大小,共计254个bucket
FREE LISTS:
Bucket 0 size=32
Bucket 1 size=40
Bucket 2 size=48
Bucket 3 size=56
Bucket 4 size=64
Bucket 5 size=72
Bucket 6 size=80
Bucket 7 size=88
Bucket 8 size=96
Bucket 9 size=104
中间略
Bucket 250 size=12352
Bucket 251 size=12360
Bucket 252 size=16408
Bucket 253 size=32792
Bucket 254 size=65560
Total free space = 0
接着是一个预备的空闲可用的列表,格式同上,也是记录很多个bucket
RESERVED FREE LISTS:
Reserved bucket 0 size=32
Reserved bucket 1 size=4400
Reserved bucket 2 size=8216
Reserved bucket 3 size=8696
Reserved bucket 4 size=8704
Reserved bucket 5 size=8712
Reserved bucket 6 size=8720
Reserved bucket 7 size=9368
Reserved bucket 8 size=9376
Reserved bucket 9 size=12352
Reserved bucket 10 size=12360
Reserved bucket 11 size=16408
Reserved bucket 12 size=32792
Reserved bucket 13 size=65560
上述区extent中的chunk中的未使用过的chunk,注意后面的 " "
Chunk 09e000088 sz= 839496 R-free " "
而且可见chunk的信息是记录在每个bucket中
标明上述预备的空闲可用空间的大小为839496,刚好就是上述哪个chunk
Total reserved free space = 839496
未PIN住的可以重建或重用的chunk列表(lru优先,关于LRU还要研究),如下包括很多CHUNK
UNPINNED RECREATABLE CHUNKS (lru first):
Chunk 0a3bd5420 sz= 56 recreate "fixed allocatio" latch=0x9e5c8db0 --CHUNK地址,大小,状态及类型,CHUNK对应的LATCH地址,经在TRC文件查找,可以和TRC文件第一部分的LATCH关联起来
Chunk 0a3bc7fb8 sz= 56 recreate "fixed allocatio" latch=0x9e5c7d10 --fixed allocatio对应x$ksmsp的ksmchcom,可以理解为CHUNK的名称
中间略
Chunk 0a3ba1a78 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3ba1848 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
SEPARATOR
Chunk 0a3bb2340 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3bb2110 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
中间略
Chunk 0a3b631e0 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3b62fb0 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3b62d80 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
Chunk 0a3b62b50 sz= 560 recreate "KQR PO " latch=0x9e5c7d10
标明上述未PIN住的空间大小
Unpinned space = 221984 rcr=78 trn=322
永久或持久的CHUNK列表,同上理,包括很多个CHUNK,不过这里仅一个CHUNK,且其类型为PERM,而且没有LATCH保护
PERMANENT CHUNKS:
Chunk 09e0cd000 sz= 15937536 perm "perm " alo=8424224
Permanent space = 15937536
标明上述永久的CHUNK空间的大小
我们继续分析
--x$ksmsp记录共享池中chunk的相关信息,可见共计20917个CHUNK
SQL> select count(*) from x$ksmsp;
COUNT(*)
----------
20917
查询上述 未PIN住的可以重建或重用的chunk列表 第一个CHUNK
SQL> select addr,ksmchidx,ksmchcom,ksmchptr,KSMCHCLS,ksmchsiz,ksmchtyp,ksmchdur from x$ksmsp where ksmchcom='fixed allocatio' and ksmchsiz=56 and KSMCHCLS='recr' and ksmchptr='00000000A3BD5420';
ADDR KSMCHIDX KSMCHCOM KSMCHPTR KSMCHCLS KSMCHSIZ KSMCHTYP KSMCHDUR
---------------- ---------- ---------------- ---------------- -------- ---------- ---------- ----------
00002B0CBA8B5548 1 fixed allocatio 00000000A3BD5420 recr 56 72 2
由下可见TRC文件第一部分LATCH对应V$LATCH_chidlren,且注意:ADDR为小写,不要用大写,否则查询不到信息
SQL> select addr,latch#,level#,name from v$latch_children where lower(addr) like '%a4222c98%';
ADDR LATCH# LEVEL# NAME
---------------- ---------- ---------- --------------------------------------------------
00000000A4222C98 29 0 ksfv messages
但是仍然找不到shared pool latch
加大DUMP级别看看,可否找到shared pool latch
SQL> oradebug setmypid
Statement processed.
SQL> oradebug dump heapdump 10
ORA-00085: current call does not exist
SQL> oradebug dump heapdump 6
Statement processed.
SQL> oradebug tracefile_name
/home/ora10g/admin/ora10g/udump/ora10g_ora_8143.trc
还是找不到shared pool latch,转换思路,先HANG shared pool latch,再查看DUMP文件,看可否有,如还没有,就是我分析思路不对
SQL> oradebug setmypid
Statement processed.
SQL> oradebug poke 0x00000000600E7AF0 4 1
BEFORE: [0600E7AF0, 0600E7AF4) = 00000000
AFTER: [0600E7AF0, 0600E7AF4) = 00000001
SQL> oradebug setmypid
Statement processed.
不过好现如果HANG SHARED POOL LATCH,发现oradebug dump heapdump 6 也hang住了
SQL> oradebug dump heapdump 6
只能以PRELIM方式先恢复SHARED POOL LATCH
[ora10g@seconary ~]$ sqlplus -prelim '/as sysdba'
SQL*Plus: Release 10.2.0.5.0 - Production on Thu Nov 19 07:37:53 2015
Copyright (c) 1982, 2010, Oracle. All Rights Reserved.
SQL> oradebug poke 0x00000000600E7AF0 4 0
ORA-00074: no process has been specified
SQL> oradebug setmypid
Statement processed.
SQL> oradebug poke 0x00000000600E7AF0 4 0
BEFORE: [0600E7AF0, 0600E7AF4) = 000000FF
AFTER: [0600E7AF0, 0600E7AF4) = 00000000
发现heapdump 3也不行会HANG
SQL> oradebug setmypid
Statement processed.
SQL> oradebug dump heapdump 3
Statement processed.
这样,HANG住CHILD#=2的shared pool latch,看什么情况,最后发现也会HANG住,可能因为不是一个子池的原因,深入原因还要研究
SQL> oradebug setmypid
Statement processed.
SQL> oradebug poke 0x00000000600E7B90 4 1
BEFORE: [0600E7B90, 0600E7B94) = 00000000
AFTER: [0600E7B90, 0600E7B94) = 00000001
感谢你能够认真阅读完这篇文章,希望小编分享的“为什么oracle 10.2.0.5只会获取child#=1的shared pool latch”这篇文章对大家有帮助,同时也希望大家多多支持创新互联,关注创新互联行业资讯频道,更多相关知识等着你来学习!
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