What is online redo log files in Oracle?
Every Oracle database has a set of two or more online redo log files. The set of online redo log files is collectively known as the redo log for the database. A redo log is made up of redo entries, which are also called redo records. The online redo log stores a copy of the changes made to data.
Where is Oracle redo log file?
The V$LOGFILE view can be used to find the datafiles for the redo logs. SVRMGR> select * from V$LOGFILE; GROUP# STATUS MEMBER —— —— —————————— 1 /t01/oradata/MYDB/redo.
How add redo log in Oracle?
To create new redo log members for an existing group, use the SQL statement ALTER DATABASE with the ADD LOGFILE MEMBER clause. The following statement adds a new redo log member to redo log group number 2: ALTER DATABASE ADD LOGFILE MEMBER ‘/oracle/dbs/log2b.
How do I redo multiplex log files?
When redo log files are multiplexed, LGWR concurrently writes the same redo log information to multiple identical redo log files, thereby eliminating a single point of redo log failure. Multiplexing is implemented by creating groups of redo log files. A group consists of a redo log file and its multiplexed copies.
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.
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.
What is the use of redo log files?
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.