Redo Log Groups Wizard (Oracle)

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A redo log makes it possible to replay SQL statements because a redo log stores all changes made to a database as they occur. If something unanticipated happens to a datafile, you can restore a backed-up datafile and use the redo log to bring the datafile back to the state it was in before the unanticipated activity. The redo log can consist of two parts: the online redo log and the archived redo log. In archive log mode, redo log files will not be overwritten unless they have been archived somewhere. Each log is a member of the group.

Note: Redo should not be confused with Undo, which is a transaction based process.

If you find that you have problems with redo log group availability and Oracle consistently has to wait for redo log groups to become free, you can create additional redo log groups. DBArtisan lets you create additional redo log groups to ensure that there is always a recycled redo log group available.

The Redo Log Group Wizard lets you:

  • Assign a number to the new redo log group and determine the file size for the group members.
  • Choose a thread for the redo log group for Oracle Parallel Server.
  • Add redo log members with the Add Redo Log Member dialog.

To Open the Redo Log Wizard

  1. On the Navigator/Explorer, find the datasource where you want to create a redo log and expand the Storage node.
  2. Right-click the Redo Log Groups node, and select New.

The table that follows describes the fields you may encounter as you complete the wizard.

Required Information Description

Do you want to use Oracle Managed Files (OMF) for the redo log group? You must be set up to use OMF to use this option

Lets you specify to use Oracle Managed Files to automatically create the redo log group. Oracle automatically creates and removes operating system files as you create and drop storage objects.

Note: If you select OMF, you do not have to enter a redo log group number or file size.

What is the group number for the redo log group?

When numbering your redo log groups, it is better not to skip numbers (e.g., 5, 10, 15). Skipping numbers causes Oracle to consume extra space in the control files of the database.

What file size should the group’s redo log members be? Note: All members of the group must be the same. With OMF, you can let Oracle assign a size or enter it manually.

size in KB or MB

To which thread should the redo log group be added?

For this option to be available, you need to be using Oracle with the parallel server option in parallel mode.

OPTIONAL: If you are using Oracle Parallel Server, type the thread. A thread is an operating system component that allows the logic of multiuser applications to be performed as several separate, asynchronous execution paths. Threads help ensure that work is being performed for some user connections even when other connections are blocked (for example, when waiting for a disk read or write operation to complete).

Add redo log group members

The name of each group member should be a file name. For example, D:\ORACLE\ORADATA\FINANCEDB\REDO02.LOG is a valid group member name. If you do not specify a full path, DBArtisan creates files in either the default or current directory of the database server.