Re: logfile questions

Rollback segments capture the "before image" of data as it existed prior to the start of a transaction. Queries by other users against the data that is being
changed will return the data as it existed "before" the change began.

The number and size of rollback segments available are specified by the DBA during creation.The database assigns transactions to rollback segments in a round-robin
fashion.

Rollback segments are designated as "public" or "private" depending on whether
it is available to a single instance ot multiple instances that access the database.

The online redo log files store the records of each transaction in the database.Each
database must have at least two redo log files availbale to it. The database will write
to one log file in a sequential fashion until it is filled, and then it will start writing to the second redo log file. When the last redo log file is filled, the database will begin
overwriting the contents of the first redo log file with new transactions.

Let me know if this helped.

Chinna
L. Tseng <lesliet_at_u.washington.edu> wrote in article <609812$p62$1_at_nntp6.u.washington.edu>...
> Hi, Oracle experts,
>
> Help with the following questions will be very appreciated.
>
> 1. What's the criteria when decieding how big/many logfile should be?
> 2. Having one big logfile (for example, 100MB) or having 4 logfiles
> with 25MB each; which one is recommended?
> 3. What's the difference between logfile and rollback segment?
>
> Thank you in advance.
>
> Leslie
> ~
>
Received on Wed Sep 24 1997 - 00:00:00 CEST