Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
Home -> Community -> Usenet -> c.d.o.server -> Instance Recovery Question
Hi,
I was training a new DBA on how Oracle handles recovery from instance failure (i.e., roll forward, roll back), and I came across this unusual little scenario that I am unclear on:
A change is made to a data block
That change is recorded in a rollback block
Change also recorded in log buffer
DBWR writes data block to disk
Instance crashes
- Change in log buffer not written to disk yet
Two Solutions:
1) Oracle always writes out the rollback block before the changed data
block.
2) Oracle always waits to flush a change in log buffer to disk before
writting the changed block (data or rollback)
2 sounds unlikely to me, so I'm going with 1.
I'm I correct?
Thanks!
Alan.
--
Alan Gano
http://home.att.net/~alangano/index.html
Received on Wed Dec 02 1998 - 23:12:08 CST