redo generation. As I found the below statement in another forum."Undo segment generates the redo data also, because undo segment is database changes, so it generates the redo data also."
How a Undo segment can generate Redo and Undo datas.
I have oracle 9i running on HP-UX, I would like to find how much redo we are generating in a given period of time, is there any script that I can use to get this information?
View 3 Replies View RelatedRedo is getting generated very high. how to find out the reason ? database kept under 2 node cluster. chcked alert log trace and log writer trace files. pasted the content as below:
--alert log trace from node1 ( node2 also has same type of message ). Archive destination disk group - TXCOM_BACKUP_01 having enough space ( 80gb )
Mon Jan 7 00:49:10 2013
Thread 1 advanced to log sequence 448546 (LGWR switch)
Current log# 1 seq# 448546 mem# 0: +TXCOM_DATA_01/txcom/onlinelog/group_1.274.785770579
Current log# 1 seq# 448546 mem# 1: +TXCOM_DATA_01/txcom/onlinelog/group_1.302.802265189
Mon Jan 7 00:49:10 2013
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In the alert log, I am able to see the archive destination disk group ( TXCOM_BACKUP_01 ) is getting DISMOUNTED and again getting MOUNTED during every archive file generation. .
Mon Jan 7 00:49:20 2013
SUCCESS: diskgroup TXCOM_BACKUP_01 was mounted
SUCCESS: diskgroup TXCOM_BACKUP_01 was dismounted
SUCCESS: diskgroup TXCOM_BACKUP_01 was mounted
SUCCESS: diskgroup TXCOM_BACKUP_01 was dismounted
archive destination parameter in both nodes are not configured. it should read diskgroup name. ( +TXCOM_BACKUP_01 ) and corresponding size limit. Should i configure this ?
SQL> show parameter db_recovery
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest string
db_recovery_file_dest_size big integer 0
[code]...
should i bring the database to mount stage and set log_archive_max_proesses to high count ? now value is 2 ( default )
We had our production database hosted on Oracle 9.2.0. Few months back we have migrated it to Oracle 10.2.0.4.0. After Migration I have noticed that redo generation has become very very high. In earlier case no. of log files generating in production hours were around 30 where as after migration it become around 200 files per day. I have run statspack report on this database. Report is saying that db block change & disk write is become very high. Parameter timed_statistics has also been set to FALSE. Even then there is not any reduction on no. of log file generation. I had used import export for upgrading the databases.
View 13 Replies View RelatedWe are facing one issue on one of the database. The database is generating large trace files(14000) from last two days. That consumes around 15G space on the disk. And the content of the trace files is not having any meaningful message to debug:
cat /apps/oracle/admin/fs90uat/bdump/fs90uat_p050_23966.trc
*** TRACE DUMP CONTINUES IN FILE /apps/oracle/admin/fs90uat/bdump/fs90uat_p050_23966.trc ***
Dump file /apps/oracle/admin/fs90uat/bdump/fs90uat_p050_23966.trc
*** TRACE DUMP CONTINUED FROM FILE /apps/oracle/admin/fs90uat/bdump/fs90uat_p050_23966.trc ***
... (Many lines with above message)
The alert log is having one repeated error yesterday:
Thu May 6 22:00:03 2010
Errors in file /apps/oracle/admin/fs90uat/bdump/fs90uat_j000_11811.trc:
ORA-12012: error on auto execute of job 2647927
ORA-04063: ORA-04063: package body "ORACLE_OCM.MGMT_DB_LL_METRICS" has errors
ORA-06508: PL/SQL: could not find program unit being called: "ORACLE_OCM.MGMT_DB_LL_METRICS"
ORA-06512: at line 1
The corresponding trace file is having error:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORACLE_HOME = /apps/oracle/product/10.2.0/db_1
System name: SunOS
Node name: corpqadb30
[Code] .......
How to Find Out Which SQL Statements Causing excessive Redo generation?
View 3 Replies View RelatedI have created 5 materialize view with REFRESH FORCE option.
REFRESH is done with every 10 min.
My destination database is MySQL.
DBlink is created in ORACLE 10g
Materialize view is created using DBLINK.
Since refresh materialize view done with every 15 min, my Redo generate gone on toss.System is generating 1 redo file for 1 min. The size for redo log is 500MB.Since materialize views are created base on mysql table, system is doing complete refresh every time which causing to generate more and more redo.
Is there any setting/option/or solution to reduce high redo generation.
I have a question on export dump file generation.
select sum(bytes)/(1024*1024*1024) "GB" from dba_segments where owner='JACK';
The above select query give the output of Schema size with 15 GB. When i perform the same schema export, the dump file size generating is 2 GB. What is the difference between the two scenarios as how come there could be a variation in file size?
on weekends we have too many archive logs generated .i have taken the data of a week and found that average archive log generated from monday to friday is 7 files per day but on satuarday and sunday the average is 60 files and FG1 gets full. on weekends we have all type of backups running like incremental,archival and logical backups and on sunday we have full physical backup
what is the reason of too many archive log files generations at weekends. is it due to hot and logical backups , if yes then how ?
I am trying to generate dynamic control file, as the files I want to upload are coming from different source and their name is constantly changing but following a fix pattern and naming convention.
I am able to generate dynamic control file through SQL. But while calling from BATCH file, i am unable to sent the file name as parameter.
All the examples i have searched are for UNIX, how to do it with BATCH File in WINDOWS.
i am using oracle 10g on solaris 10 os.currently archived log is generated by size wise 52 mb.i want to know whar is the best practice for archive log generation . it should be time interval or size wise.
View 1 Replies View RelatedI learnt that logWriter writes in the redo log files when redo log buffer is 1/3 full, it means that 66 % of redo log buffer are always empty and never used,
if no, isn't a waste of memory (66 % always empty !)
I've a situation where I've very less redo logs generated. Let us say 10MB. Which solution will be better ?
1. Create one redo log group about 12 MB in size.
2. Create two redo log groups about 5 MB each in size as recommended by Oracle.
Even though solution 1 is also appropriate for me because I've less redo generated than the redo log group size. My whole redo will fit in this and I can raise checkpoint forcefully after certain period of time let us say every 3 seconds.
In one of our DB I found scenario one is implemented. So I want to know pros and cons of both of these practices.
I have some doubts about redo log files,
1) Can we fetch 'select statements' from redo log files through the use of log miner utility or any other?
(I think redo log file contains only insert,update,delete and DDL/DCL commands only)
2) If "No" to the above answer then how can i fetch all select statements fired on the system for a day or particular time.
(setting of sql_trace may be the one of them, but can it be possible for system level)
Today i noticed one problem with my database,my redologs switches in every 3mins,i also noticed there is no more transaction changes happening in database but still redo switches.
Fri Oct 05 06:10:05 2012
Thread 1 advanced to log sequence 79244
Current log# 2 seq# 79244 mem# 0: D:ORADATAORACIREDO02.LOG
Fri Oct 05 06:12:16 2012
Thread 1 advanced to log sequence 79245
Current log# 1 seq# 79245 mem# 0: D:ORADATAORACIREDO01.LOG
Fri Oct 05 06:14:28 2012
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why redo switch happening,any internal problem causes redo to switch .
SQL> update t set a = 1 where b = 2; -- must have redo record
2 rows updated.
SQL> rollback;
the above redo record that uncommit changed must be written from redo buffer to the online redo logfile. why Oracle write the redo record that uncommit changed to the online redo logfile ? when it will be used?
Whenever any transaction happen in database redo has generated for this transaction. Do select statement treat as a transaction as it doesn't modify any thing in database. And If select statement should not be a transaction, there should not be any redo generation for select statement.
So is select statement generate redo? If yes then Why ?
understanding a redo/undo concept . Refer following data
create table t(n number);
insert into t values(10);
commit;
now I update as following
update t set n=20;
As per my understanding the before image i.e. n=10 is stored in undo (to be used for rollback, transaction recovery and even in instance recover but not in media recovery) and after image n=20 is stored in redo (to be used for various recovery purposes including media recovery in case of consistent backup).
So it is redo logs for rolling forward and undo for rolling back making transaction, db consistent . If my above understanding is true then what is meant by the term 'redo required for undo'?
Also, if there are 2 database db1 and db2 connected using database link where we are populating t1 table in db1 using t2 table in db2 using db link where redo and undo will be updated db1 or db2?
When i was starting my database .there was an error
ora-00333:redo log read error block 203 count 8192.
We have one primary oracle database 10.2 and standby by database with no data guard. Initially we have 2 redo log group in primary and standby database.
We have recently add 2 more redo log and increase the size of log member from 50m to 200m in primary database. We don't have any problem in primary database.but in standby database we face a problem because we cannot open it. It always in mount stage in which . How we change the size of current redo log because we can't run. Alter system switch logfile command in mount stage.
Here is my situation.
1. I generate file_name through a function.
2. File name like File_DD_MM_YY_FLXXX.
3. Now this FLXXX is the filenumber. It will be 1 for the 1st run of the day and for each of the new run it will be +1. Again next day it will start from 1.
So right now I am using a sequence and resetting it at 12 AM to 0. Is it a good approach to solve the scenario?
Im generating a csv file using TEXT_IO Utility.The file generated contains one blank line at the last record.Say there is 10 records. Open the generated csv file in notepad and move the cursor down. After 10 records, the cursor will move down one more time.
How to avoid that blank line as im using cursor in my script. The script is attached below.
Version:
Oracle 9i Database
Oracle Forms 6i
I have written a Java class which generate and place the XML file in a particular location. This the java class is loaded into Oracle using the loadjava command. When I call the sql java procedure java classn will be called and the XML file is generating.
But my problem is with xml header i.e in the header it is getting as
<?xml version = '1.0' encoding = 'UTF-8'?>
Where as I am generating the xml file from by just java call instead from Oracle the header is as follows
<?xml version="1.0" encoding="UTF-8" ?>
I am thinking that this could be reason with different jar using Oracle side.
Give me the pls / sql trigger code to generate an xml file for a table.Say for example employees table.
View 13 Replies View Relatedi have two tablespaces dictionary managed (SYSTEM,APPLSYSX) i tried to change to locally cause it will cause problem in future when trying to run OATM migration.i did it successfully on APPLSYSX,when i did it on system upon oracle procedure.i have to change all tablespaces to read only when i did that with tablespace APPLSYSD(alter tablespace APPLSYSD read only) i received errors
SQL> alter tablespace APPLSYSD READ ONLY;
alter tablespace APPLSYSD READ ONLY
*
ERROR at line 1:
ORA-01230: cannot make read only - file 636 is offline
ORA-01111: name for data file 636 is unknown - rename to correct file
ORA-01110: data file 636: '/vol5u/oracle/prddb/9.2.0/dbs/MISSING00636'
i have not this file on the OS
what exactly redo log file contains.? whether they contained the ddl or dml statements or more than that.........?
View 1 Replies View RelatedThe REDO log file size is important DB performance issues when DB is run archivelog mode.If DB run noarchivelog mode, REDO log file size not impact to DB performance.
View 3 Replies View RelatedI have a standalone DB of version 10.2.04.I am facing log file parallel write as one of the top events.I have increased the REDO log file size to 500m.But even then REDO switching is happening frequently.
select group#, bytes, archived, status, first_change#, first_time from v$log order BY first_change#;
GROUP# BYTES ARC STATUS FIRST_CHANGE# FIRST_TIME
---------- ---------- --- ---------------- ------------- ----------
10 262144000 NO INACTIVE 8509999 30-08-2012
12 524288000 NO INACTIVE 8612142 30-08-2012
11 262144000 NO INACTIVE 8676390 30-08-2012
9 262144000 NO CURRENT 8706330 30-08-2012
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I would like to make a change on the live system!I have read a book and found a information about REDO log file size is impact on DB performance.My DB current log file size is 100 MB. But, Oracle 10g's Redo Logfile Sizing Advisor offer the optimal log file size is 1845 MB.What REDO log file size is best for my Oracle database?
#Optimal log file size:
select optimal_logfile_size
from v$instance_recovery
----------------------------
OPTIMAL_LOGFILE_SIZE
1842
[code]....
I try to current redo log file location to multiplex redo log configuration. I did do this on the DB.I import a backup file to DB when I made this change, but its too slow running import process from old configuration. Approximately it is 4 times slow.
when I recovery old configuration for redo log file, import process is normal running...Why this changes hit to DB import process performance? The old redo log file location is below:
GROUP#MEMBERBYTES
4"/crtest1/oradata/redo04a.log"524288000
4"/crtest1/oradata/redo04b.log"524288000
3"/crtest1/oradata/redo03a.log"524288000
3"/crtest1/oradata/redo03b.log"524288000
2"/crtest1/oradata/redo02a.log"524288000
2"/crtest1/oradata/redo02b.log"524288000
1"/crtest1/oradata/redo01a.log"524288000
1"/crtest1/oradata/redo01b.log"524288000
The new multiplex redo log file location is below:
GROUP#MEMBERBYTES
4"/crtest1/oradata/redo04a.log"524288000
4"/opt/redolog/redo04b.log"524288000
3"/opt/redolog/redo03a.log"524288000
3"/usr/redolog/redo03b.log"524288000
2"/usr/redolog/redo02a.log"524288000
2"/disk1/redolog/redo02b.log"524288000
1"/disk1/redolog/redo01a.log"524288000
1"/crtest1/oradata/redo01b.log"524288000
I think that new configuration is better for old configuration at security issue.Here is the disk partitions on the server:
-bash-3.00$ df -lh
Filesystem size used avail capacity Mounted on
/dev/dsk/c0t0d0s0 9.6G 2.2G 7.3G 23% /
/devices 0K 0K 0K 0% /devices
ctfs 0K 0K 0K 0% /system/contract
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