when do the logfiles get updated ??

[yanban]

Hi all,

I can read everywhere and I have now assumed that when you issue a commit, LGWR writes the entries from the redo log buffer to the current online redolog file.

So, I made this test ( on W2000/8.1.7) :

-In Windows explorer, the latests modifications done on my database's files is today at 19.20 ( on the logfiles).
( I refreshed the screen and ordered by the 'last modification' column)

- Now ( current time is 19.29) I go to sql+ and do an updated ( followed by a commit) on one of my DB's tables.

- I query this table and of course, the change is effective.

- Now I go back to Explorer.
I was expected to see that one of my logfile got updated at 19.29 (after the commit). But no, it still shows 19.20.

- Just done an alter system switch logfile and then it got updated ( that was just to be sure I was looking at the right files! ).

SO why is that ? is it because of a kind of HD controler? Am I missing something ?

THanks?

[hrishy]

Hi Yanbaan

Cool..i would want ot test your thingy..but before that does windows 2000 use asynchronous writes ?if yes then it si easy to explain..i dont have win2000 i will test on winnT and get back to ya..

hey you could have posted this to database administration forums rather than certification forum where this kind of a question is more likely to get noticed..

regards
Hrishy

[hrishy]

Hi Yanbaan


Dude i like your handle its kinda of cool ;-D..well for the problem i discovered its a windoze thingy as i cannot reproduce your result on a unix box..and i can do this on windows NT..well here is the explanation..windoze just cant update a open file :-D

when you say

a)alter system switch logfile

or

b)alter system checkpoint

the logfile is closed by oracle and windows can update it..here the files are opened by the oracle process ..

one of the subtle differences on how oracle behaves on windows and how it behaves on unixes..

regards
Hrishy

[yanban]

Hi Hrishy,

Thanks for your good answer because that was kind of worring me!

I lately installed linux on the same machine,I really need to learn a bit more about it and install Oracle on it! ( will do that when I will have finished the OCP....)

Cheers.

[hrishy]

Hi Yanban

well..well..thats the way to go for OCP even i did my ocp that way first i installed Linux then i installed oracle8i on and started experimenting..its really a great way to learn..you will not only clear OCP but you can be confident of oracle as well as unix..

regards
Hrishy

[yanban]

You're right hrishy and as far as I have looked, so far Linux seems really interesting to me... but that was already quite challenging to setup a multiboot ( I wanted both OS on the same unique HD)and working for the OCP ( I passed P&T last monday) as well as going to work everyday.... Getting to know a new OS will be a bit too much at the moment (or my girlfriend will leave me!)
I will clear OCP (2 to go) and then install a new HD to have room to put Oracle on linux afterwards.

(... and When I think that I have just received Thom Kite's books few weeks ago, I really need more than 24H in a day...

[adrianomp]

(... and When I think that I have just received Thom Kite's books few weeks ago, I really need more than 24H in a day...

Every time I see that book I wish to throw it away. Not because of the book itself (it's very good). The problem is that I bought it on a bookstore translated to brazilian portuguese. Absolutely terrible.

Imagine the word "instance" translated to something like "copy". Technical books should be translated by technical people, but maybe it is impossible to happen. :/

[hrishy]

Hi Yanban

you gotta partition your harddrive..

1)first install windoze
2)make logical partitioning of your harddisk
3)then install redhat or suse they are very very easy to install

You can find more about installations at www.linuxfocus.org..i gues french is ur native or is it dutch you can find them in your native language at the website..

best of luck with your exams..

regards
Hrishy