How do I reduce the redo log in Oracle?
Now drop redo log groups 1, 2, and 3: SQL> alter database drop logfile group 1; SQL> alter database drop logfile group 2; SQL> alter database drop logfile group 3; Verify the groups were dropped, and the new groups’ sizes are correct.
What is redo log file in Oracle database?
Redo log files are operating system files used by Oracle to maintain logs of all transactions performed against the database. The primary purpose of these log files is to allow Oracle to recover changes made to the database in the case of a failure.
How many redo log groups should I have?
two redo log groups
Every database must have at least two redo log groups. Redo log files contain all the information necessary to recover lost data in your database. Every SQL statement that you issue changing data can be reconstructed by the information saved in these files.
How do I make redo log active?
If ACTIVE, switch the log (ALTER SYSTEM SWITCH LOGFILE) and wait until the status is INACTIVE. Next, drop the online redo log (with the ALTER DATABASE DROP LOGFILE GROUP x) command. With the group removed, add the group anew in the new location (ALTER DATABASE ADD LOGFILE command.
Can we resize redo log file?
We cannot resize the redo log files. We must drop the redolog file and recreate them . When a redo log member is dropped from the database, the operating system file is not deleted from disk. Rather, the control files of the associated database are updated to drop the member from the database structure.
How do I change the size of my redo log?
select group#, status from v$log; You may have to run the alter command up to three times to get group 1 to be CURRENT. Repeat steps 1 to 7 for group 2, group 3, and group 4. Confirm the size change to each group is now 165 Mb.
How do I find the current redo log file?
The V$LOGFILE view can be used to find the datafiles for the redo logs.
How do you calculate redo log?
I discovered that I have 15 groups of 2 GB, so the redo log group size is 30 GB. Oracle says that “In general we recommend adding an additional 30% on top of the peak rate”, so that would mean I am expected to have 245mb/s*1.3 = 318.5 MB/S.
Can I have redo log groups with different size?
All members of the same multiplexed redo log group must be the same size. Members of different groups can have different sizes. However, there is no advantage in varying file size between groups.
When should I increase redo log size?
As a general rule of thumb, Oracle recommends that you size your online redo logs not to switch more then 5 times per hour during peak DML times.
How do I restore a redo log file?
To recover from loss of an active online redo log group in ARCHIVELOG mode:
- Begin incomplete media recovery.
- Ensure that the current name of the lost redo log can be used for a newly created file.
- Open the database using the RESETLOGS option:
How do I change the redo log size in Oracle?
Beginning with Oracle Database 11g Release 2, you can specify the block size of online redo log files with the BLOCKSIZE keyword in the CREATE DATABASE , ALTER DATABASE , and CREATE CONTROLFILE statements. The permissible block sizes are 512, 1024, and 4096.
How to increase size of redo log files?
Oracle redo log size increase in Oracle 12C Run the below query as “SYS AS SYSDBA” and get the Logfile name with location, redo log size and group number. Run the below query and check status of the log file group. Status should be “INACTIVE” to update the log file size. Run the below query to switch the status between ACTIVE and CURRENT. Run the below query to drop the logfile group.
What is the purpose of redo log files?
Main purpose of redo log file in database is to keep a record about all activities that are happening during a transaction. It helps to retrieve the changes that are not stored properly.
How to resize redolog file in Oracle?
we cannot drop the current and active redo log file .
How often to redo log file should switch?
There should not be frequent log switches per hour.