请教归档日志大小的问题

lujiaguai

唐老师，今天看到某野生数据库，如下的归档日志，大小不一，平均30多M出头的样子
但实际上，在线日志是维持在默认的50M大小，按说如此的话，归档日志也应该是50M一个才对
为什么会出现下面这样大小不规则的情况。
是因为日志切换太繁忙，来不及写导致的吗？

如下：
-rw-r----- 1 oracle oinstall 28168704 Mar 30 06:28 o1_mf_1_69684_dfrf7yfp_.arc
-rw-r----- 1 oracle oinstall 28211712 Mar 30 06:48 o1_mf_1_69685_dfrggcnb_.arc
-rw-r----- 1 oracle oinstall 28191744 Mar 30 07:06 o1_mf_1_69686_dfrhhv2h_.arc
-rw-r----- 1 oracle oinstall 28479488 Mar 30 07:12 o1_mf_1_69687_dfrhvl8d_.arc
-rw-r----- 1 oracle oinstall 28605440 Mar 30 07:18 o1_mf_1_69688_dfrj6kg1_.arc
-rw-r----- 1 oracle oinstall 28260864 Mar 30 07:23 o1_mf_1_69689_dfrjjdlm_.arc
-rw-r----- 1 oracle oinstall 28539904 Mar 30 07:28 o1_mf_1_69690_dfrjs0q2_.arc
-rw-r----- 1 oracle oinstall 28645376 Mar 30 07:32 o1_mf_1_69691_dfrk07tq_.arc
-rw-r----- 1 oracle oinstall 40193536 Mar 30 07:36 o1_mf_1_69692_dfrk8p0y_.arc
-rw-r----- 1 oracle oinstall 41025024 Mar 30 07:37 o1_mf_1_69693_dfrk9frq_.arc
-rw-r----- 1 oracle oinstall 50490368 Mar 30 07:37 o1_mf_1_69694_dfrk9s4m_.arc
-rw-r----- 1 oracle oinstall 42354176 Mar 30 07:37 o1_mf_1_69695_dfrk9tsw_.arc
-rw-r----- 1 oracle oinstall 36489728 Mar 30 07:37 o1_mf_1_69696_dfrkb023_.arc
-rw-r----- 1 oracle oinstall 28477440 Mar 30 07:40 o1_mf_1_69697_dfrkj35s_.arc
-rw-r----- 1 oracle oinstall 28630016 Mar 30 07:44 o1_mf_1_69698_dfrkq49n_.arc
-rw-r----- 1 oracle oinstall 28761088 Mar 30 07:48 o1_mf_1_69699_dfrkxmfw_.arc
-rw-r----- 1 oracle oinstall 28732928 Mar 30 07:52 o1_mf_1_69700_dfrl6jkv_.arc
-rw-r----- 1 oracle oinstall 28718080 Mar 30 07:57 o1_mf_1_69701_dfrlgyr9_.arc
-rw-r----- 1 oracle oinstall 28791808 Mar 30 08:01 o1_mf_1_69702_dfrlowty_.arc
-rw-r----- 1 oracle oinstall 28662784 Mar 30 08:05 o1_mf_1_69703_dfrlyt1p_.arc
-rw-r----- 1 oracle oinstall 28491264 Mar 30 08:11 o1_mf_1_69704_dfrm9452_.arc
-rw-r----- 1 oracle oinstall 30586368 Mar 30 08:30 o1_mf_1_69705_dfrnfpqc_.arc
-rw-r----- 1 oracle oinstall 28175872 Mar 30 08:57 o1_mf_1_69706_dfrozsl4_.arc
-rw-r----- 1 oracle oinstall 29877248 Mar 30 09:05 o1_mf_1_69707_dfrpgzrb_.arc

botang

怀疑频繁手工切换（应用中写了）。

lujiaguai

有必要再听一节课
我感觉不是应用当中切换了，是写的太频繁导致
之前问过Checkpoint not complete的相关疑问，得到的答案是当前没有问题，但如果继续下去越来越严重的话，今后可能某天会出问题
Checkpoint not complete跟归档日志大小不一致有关吗？

Fri Mar 31 09:29:26 2017
Archived Log entry 118718 added for thread 1 sequence 119007 ID 0x7bc442a1 dest 1:
Fri Mar 31 09:30:14 2017
Thread 1 cannot allocate new log, sequence 119009
Checkpoint not complete
  Current log# 1 seq# 119008 mem# 0: /u2/oradb/oradata/topprod/redo01.log
Thread 1 advanced to log sequence 119009 (LGWR switch)
  Current log# 2 seq# 119009 mem# 0: /u2/oradb/oradata/topprod/redo02.log
Fri Mar 31 09:30:17 2017
Archived Log entry 118719 added for thread 1 sequence 119008 ID 0x7bc442a1 dest 1:
Fri Mar 31 09:30:59 2017
Thread 1 cannot allocate new log, sequence 119010
Checkpoint not complete
  Current log# 2 seq# 119009 mem# 0: /u2/oradb/oradata/topprod/redo02.log
Thread 1 advanced to log sequence 119010 (LGWR switch)
  Current log# 3 seq# 119010 mem# 0: /u2/oradb/oradata/topprod/redo03.log
Fri Mar 31 09:31:02 2017
Archived Log entry 118720 added for thread 1 sequence 119009 ID 0x7bc442a1 dest 1:
Fri Mar 31 09:31:41 2017
Thread 1 cannot allocate new log, sequence 119011
Checkpoint not complete
  Current log# 3 seq# 119010 mem# 0: /u2/oradb/oradata/topprod/redo03.log
Thread 1 cannot allocate new log, sequence 119011
Private strand flush not complete
  Current log# 3 seq# 119010 mem# 0: /u2/oradb/oradata/topprod/redo03.log
Thread 1 advanced to log sequence 119011 (LGWR switch)
  Current log# 1 seq# 119011 mem# 0: /u2/oradb/oradata/topprod/redo01.log
Fri Mar 31 09:31:47 2017
Archived Log entry 118721 added for thread 1 sequence 119010 ID 0x7bc442a1 dest 1:
Fri Mar 31 09:32:35 2017
Thread 1 cannot allocate new log, sequence 119012
Checkpoint not complete
  Current log# 1 seq# 119011 mem# 0: /u2/oradb/oradata/topprod/redo01.log
Thread 1 cannot allocate new log, sequence 119012
Private strand flush not complete
  Current log# 1 seq# 119011 mem# 0: /u2/oradb/oradata/topprod/redo01.log
Thread 1 advanced to log sequence 119012 (LGWR switch)
  Current log# 2 seq# 119012 mem# 0: /u2/oradb/oradata/topprod/redo02.log
Fri Mar 31 09:32:41 2017
Archived Log entry 118722 added for thread 1 sequence 119011 ID 0x7bc442a1 dest 1:

文件系统归档日志上看
-rw-r-----  1 oracle oinstall 32370176 Mar 31 09:29 1_119007_848870689.dbf
-rw-r-----  1 oracle oinstall 33354240 Mar 31 09:30 1_119008_848870689.dbf
-rw-r-----  1 oracle oinstall 33704960 Mar 31 09:31 1_119009_848870689.dbf
-rw-r-----  1 oracle oinstall 33893888 Mar 31 09:31 1_119010_848870689.dbf
-rw-r-----  1 oracle oinstall 36207616 Mar 31 09:32 1_119011_848870689.dbf
-rw-r-----  1 oracle oinstall 31925760 Mar 31 09:34 1_119012_848870689.dbf
-rw-r-----  1 oracle oinstall 43444224 Mar 31 09:35 1_119013_848870689.dbf
-rw-r-----  1 oracle oinstall 31865856 Mar 31 09:36 1_119014_848870689.dbf
-rw-r-----  1 oracle oinstall 40258560 Mar 31 09:37 1_119015_848870689.dbf
-rw-r-----  1 oracle oinstall 31588864 Mar 31 09:39 1_119016_848870689.dbf

还有这样的，一分钟内切换10次的
-rw-r-----  1 oracle oinstall 41540096 Mar 31 02:12 1_118968_848870689.dbf
-rw-r-----  1 oracle oinstall 39672320 Mar 31 02:12 1_118969_848870689.dbf
-rw-r-----  1 oracle oinstall 46902784 Mar 31 02:12 1_118970_848870689.dbf
-rw-r-----  1 oracle oinstall 41540096 Mar 31 02:12 1_118971_848870689.dbf
-rw-r-----  1 oracle oinstall 41540096 Mar 31 02:12 1_118972_848870689.dbf
-rw-r-----  1 oracle oinstall 41540096 Mar 31 02:12 1_118973_848870689.dbf
-rw-r-----  1 oracle oinstall 41733120 Mar 31 02:12 1_118974_848870689.dbf
-rw-r-----  1 oracle oinstall 41540096 Mar 31 02:12 1_118975_848870689.dbf
-rw-r-----  1 oracle oinstall 41538048 Mar 31 02:12 1_118976_848870689.dbf
-rw-r-----  1 oracle oinstall 41540608 Mar 31 02:12 1_118977_848870689.dbf
-rw-r-----  1 oracle oinstall 38744064 Mar 31 02:13 1_118978_848870689.dbf
-rw-r-----  1 oracle oinstall 41540096 Mar 31 02:13 1_118979_848870689.dbf
-rw-r-----  1 oracle oinstall 41534976 Mar 31 02:13 1_118980_848870689.dbf
-rw-r-----  1 oracle oinstall 41539072 Mar 31 02:13 1_118981_848870689.dbf
-rw-r-----  1 oracle oinstall 48730624 Mar 31 02:13 1_118982_848870689.dbf
-rw-r-----  1 oracle oinstall 41537536 Mar 31 02:13 1_118983_848870689.dbf
-rw-r-----  1 oracle oinstall 43642880 Mar 31 02:13 1_118984_848870689.dbf
-rw-r-----  1 oracle oinstall 41540096 Mar 31 02:13 1_118985_848870689.dbf
-rw-r-----  1 oracle oinstall 42697216 Mar 31 02:13 1_118986_848870689.dbf

botang

lujiaguai 发表于 2017-3-31 09:50
有必要再听一节课
我感觉不是应用当中切换了，是写的太频繁导致
之前问过Checkpoint not complete的相关 ...

日志文件太小，或不对称造成。