| Variable file size for archive log files [message #486499] |
Thu, 16 December 2010 01:30  |
jimit_shaili
Messages: 237
Registered: June 2006
Location: India, Ahmedabad
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Senior Member |
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Dear Friends
I'm facing problem with archive log file size, Archive logs are generated with only of 90m or 92m or 94m(Variable sizes of less than 100m), Although i had set 100m for each of my redo log file. Here i'm providing my create db script for your reference. I want to know why the log switches before it reaches 100m.Is there any connection of intial 10m for my .dbf files.
create database mydev
maxlogmembers 3
maxloghistory 100
maxdatafiles 50
maxinstances 1
logfile
group 1
('/ora11gdb/odb/oh1/oradata/mydev/redo01a.log','/multiplex/mydev/redolog/redo01b.log') size 100m,
group 2
('/ora11gdb/odb/oh1/oradata/mydev/redo02a.log','/multiplex/mydev/redolog/redo02b.log') size 100m,
group 3
('/ora11gdb/odb/oh1/oradata/mydev/redo03a.log','/multiplex/mydev/redolog/redo03b.log') size 100m
datafile '/ora11gdb/odb/oh1/oradata/mydev/system01.dbf' size 10m autoextend on next 1m maxsize 2g
sysaux datafile
'/ora11gdb/odb/oh1/oradata/mydev/sysaux01.dbf' size 10m autoextend on next 1m maxsize 2g
default temporary tablespace wbtemp tempfile
'/ora11gdb/odb/oh1/oradata/mydev/temp01.dbf' size 10m autoextend on next 1m maxsize 1g
undo tablespace undotbs1 datafile
'/ora11gdb/odb/oh1/oradata/mydev/undotbs01.dbf' size 10m autoextend on next 1m maxsize 2g;
Regards
Jimit
[Updated on: Thu, 16 December 2010 02:41] by Moderator Report message to a moderator |
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| Re: Variable file size for archive log files [message #486510 is a reply to message #486503] |
Thu, 16 December 2010 02:23  |
jimit_shaili
Messages: 237
Registered: June 2006
Location: India, Ahmedabad
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Senior Member |
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Dear Michel
Here i'm showing my archive log files information from server and also output of parameter which you suggest.
[oracle1@WBH-DB1 archivedata]$ ll -h
total 12G
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:31 ARCH_1_737117634_100.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:32 ARCH_1_737117634_101.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:32 ARCH_1_737117634_102.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:33 ARCH_1_737117634_103.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:34 ARCH_1_737117634_104.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:35 ARCH_1_737117634_105.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:35 ARCH_1_737117634_106.ARC
-rw-r----- 1 oracle1 oinstall 86M Dec 15 16:36 ARCH_1_737117634_107.ARC
-rw-r----- 1 oracle1 oinstall 95M Dec 15 16:37 ARCH_1_737117634_108.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:37 ARCH_1_737117634_109.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:38 ARCH_1_737117634_110.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:38 ARCH_1_737117634_111.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:39 ARCH_1_737117634_112.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:40 ARCH_1_737117634_113.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:40 ARCH_1_737117634_114.ARC
-rw-r----- 1 oracle1 oinstall 91M Dec 15 16:41 ARCH_1_737117634_115.ARC
-rw-r----- 1 oracle1 oinstall 94M Dec 15 16:41 ARCH_1_737117634_116.ARC
Output of parameter archive_lag_target
SQL> show parameter archive_lag_target
NAME TYPE VALUE
------------------------------------ ----------- -----------------------------
archive_lag_target integer 0
Regards
Jimit
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| Re: Variable file size for archive log files [message #486513 is a reply to message #486510] |
Thu, 16 December 2010 02:38 |
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Michel Cadot
Messages: 68718
Registered: March 2007
Location: Saint-Maur, France, https...
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Senior Member
Account Moderator |
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No one is processing "switch log" or "archivelog current"? Maybe implicitly with backup script.
What is the size of your log buffer? If Oracle can't write the content of the log buffer inside the current log file then it switches.
Anyway, what is the problem to have different sizes?
Regards
Michel
[Updated on: Thu, 16 December 2010 02:41] Report message to a moderator |
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| Re: Variable file size for archive log files [message #486518 is a reply to message #486514] |
Thu, 16 December 2010 03:50 |
jimit_shaili
Messages: 237
Registered: June 2006
Location: India, Ahmedabad
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Senior Member |
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Dear Michel
Here i'm posting results of log_buffer parameter and answer to your dought why this much faster and frequent generation of archive files,it is because of i'm importing the data from previously taken export file. I don't have any problem with archive files less than 100m, but i prefer it should be at exact size which i set.
SQL> show parameter log_buffer
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
log_buffer integer 10584064
Regards
Jimit
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| Re: Variable file size for archive log files [message #486536 is a reply to message #486523] |
Thu, 16 December 2010 05:16 |
jimit_shaili
Messages: 237
Registered: June 2006
Location: India, Ahmedabad
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Senior Member |
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Dear Micheal
Not arguing with you, but if oracle switches if it needed then why it is parameter based and why we should have to specify size of redo log files? let oracle itself to handle it. Personally i'm not satisfied with oracle technique of handling redo files this way in 11gR2. (Assume you are right as always). I have been using Oracle 9i for last 5 years and never face such a silly problem.No regrets to you.Revert if i can provide you more information, to solve/understand above problem.
Regards
Jimit
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| Re: Variable file size for archive log files [message #486809 is a reply to message #486499] |
Mon, 20 December 2010 06:27 |
ashokanjj
Messages: 6
Registered: December 2007
Location: India
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Junior Member |
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Hai,
I have raised similar questions after migration of my db from 9i to 10g during 2008 and then I raised a SR with oracle corpn. They have replied that the archive log files will be compressed automatically.This feature is available from 10g onwards.
By
AShokan
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| Re: Variable file size for archive log files [message #486814 is a reply to message #486809] |
Mon, 20 December 2010 06:56 |
John Watson
Messages: 8960
Registered: January 2010
Location: Global Village
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Senior Member |
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Hi there - why not do the test, instead of relying on something from support? Those guys are just ordinary people like you and me (heck, they were me) and can easily misunderstand your question. See this:
C:\Users\john\home>rman target /
Recovery Manager: Release 11.2.0.1.0 - Production on Mon Dec 20 12:39:12 2010
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
connected to target database: ORCL (DBID=1264746920)
RMAN> backup archivelog all tag compresstest;
Starting backup at 20-DEC-10
current log archived
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=147 device type=DISK
channel ORA_DISK_1: starting archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=27 RECID=1 STAMP=738246768
input archived log thread=1 sequence=28 RECID=2 STAMP=738246786
input archived log thread=1 sequence=29 RECID=3 STAMP=738246827
input archived log thread=1 sequence=30 RECID=4 STAMP=738247029
input archived log thread=1 sequence=31 RECID=5 STAMP=738247174
channel ORA_DISK_1: starting piece 1 at 20-DEC-10
channel ORA_DISK_1: finished piece 1 at 20-DEC-10
piece handle=C:\ORACLE\FLASH_RECOVERY_AREA\ORCL\BACKUPSET\2010_12_20\O1_MF_ANNNN_COMPRESSTEST_6JYMN8QP_.BKP tag=COMPRESS
TEST comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:15
Finished backup at 20-DEC-10
RMAN> list backupset tag compresstest;
List of Backup Sets
===================
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
5 141.29M DISK 00:00:09 20-DEC-10
BP Key: 5 Status: AVAILABLE Compressed: NO Tag: COMPRESSTEST
Piece Name: C:\ORACLE\FLASH_RECOVERY_AREA\ORCL\BACKUPSET\2010_12_20\O1_MF_ANNNN_COMPRESSTEST_6JYMN8QP_.BKP
List of Archived Logs in backup set 5
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- --------- ---------- ---------
1 27 1576159 20-DEC-10 1600573 20-DEC-10
1 28 1600573 20-DEC-10 1601463 20-DEC-10
1 29 1601463 20-DEC-10 1602063 20-DEC-10
1 30 1602063 20-DEC-10 1602329 20-DEC-10
1 31 1602329 20-DEC-10 1602451 20-DEC-10
RMAN>
This says that RMAN did NOT compress.
Then check again, with a different tool:
SQL> select sum(blocks * block_size) from v$archived_log
2 where sequence# between 27 and 31;
SUM(BLOCKS*BLOCK_SIZE)
----------------------
148153856
SQL> select BYTES from v$backup_piece where tag='COMPRESSTEST';
BYTES
----------
148155392
SQL>
The backupset is slightly bigger than the original archives! And, of course, the final check is to look at the files with operating system utilities. It looks as though when you raised the SR, they didn't understand what you were asking.
This is why I love Oracle: whenever you aren't sure of something, it is so easy to construct a test.
[update: all of this is, of course, if you are talking about backup comprtession. I can't think of any other.]
[Updated on: Mon, 20 December 2010 07:00] Report message to a moderator |
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