Solved

rollforward

Posted on 2004-04-29
4
273 Views
Last Modified: 2008-03-10
  what is rollforwrd data in oracle after instance crash and what happens during rollforward?
0
Comment
Question by:laksirib76
4 Comments
 
LVL 12

Accepted Solution

by:
catchmeifuwant earned 30 total points
ID: 10946946
0
 

Expert Comment

by:sachinkaggrawal
ID: 10947043
when we starts any transaction in the oracle, normally we make some changes in the database tables.
Now when we commit  these changes, all the changes from dbcache are written to disk datafiles. And some SCN is generated which is stamped in the redolog files. now suppose that after commit the data from redo buffer is written to redo file. after this the commited statement will be shown to the user.

but if now before this data being written to datafiles, the instance crashed. now this commited data which is not written to datafiles is rollforward data.

when the oracle instance starts again then this data is written to datafiles during instance recovery. this process of writing data to disk, in which the oracle comes to an consistent state, which was before crash, is known as rollforwarding state.
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

APEX (Application Express) is used to develop a web application from Oracle. SQL Workshop is one of the tools that comes with Oracle APEX to query or modify the database objects or to make any changes to the structure.
SQL Command Tool comes with APEX under SQL Workshop. It helps us to make changes on the database directly using a graphical user interface. This helps us writing any SQL/ PLSQL queries and execute it on the database and we can create any database ob…
Video by: Steve
Using examples as well as descriptions, step through each of the common simple join types, explaining differences in syntax, differences in expected outputs and showing how the queries run along with the actual outputs based upon a simple set of dem…
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question