Re: Daylight Savings and Redo Logs

In article <4it19i$fce_at_inet-nntp-gw-1.us.oracle.com>, tkyte_at_us.oracle.com (Thomas J Kyte) writes:
> don't worry about it. Oracle doesn't use the system clock to figure out how
> to
> recover. It uses the scn (system commit number) to do that. The scn is sort
> of
> like an internal clock.
>

Thomas

It is a problem when you are carrying out a point-in-time recovery. Say day light
savings STARTS at 2:00 am and we put our clock back 1 hour to 1:00 AM.

So

UTC time	12:00	1:00	1:30	2:00	2:01	2:30	3:00	4:00
Local time	12:00 	1:00	1:30	2:00 	1:01	1:30	2:00	3:00
Label		A	B	C	D	E	F	G	H

This is assuming we are around UK.

Now if we loose our database at time F (1:30am). and carry out a point-in-time recovery, which time does the database use? Time F or time C. I bet you it is C, right?

Paul,

I use to worry about this but when I worked out the probability of failing in the 1 hour in question and needing a point in-time recovery, it was very small. Dont worry about it. You could also use the SCN number for recovery.

ta
tony

-- 
 _____       ________ / ___|Tony Jambu, Database and Oracle WebSys Consultant
  /_  _        /_ __ /     |Wizard Consulting,Aust (ACN 065934778)
 /(_)/ )(_/ \_/(///(/_)/_( |CIS: 100250.2003_at_compuserve.com FAX:+61-3-94163559
 \_______/                 |EMAIL:TJambu_at_wizard.com.au PHONE:+61-3-94122905