Re: How much amount of Redo Generated?

Jumma wrote:

> Hi,
>
> I wanted to find out the amount of transaction which is currently
> going on.

Why?

> In this regard I heard that the CPODR_BNO column of SYS.X$KCCCP table
> finds out the redo amount generated for the current redo log file.

Sort of.

> Via searching this google site, I found the solution of this.
>
> An expert said that:

I said it, but I'm no expert. Either attribute it, or just quote it. But don't ascribe to me qualities I wouldn't ascribe to myself.

> The column labelled CPODR_BNO shows the Current
> position of the Database Redo Block Number.
> Multiply by (usually) 512 bytes to get the position in more meaningful
> terms. For example, if it displays 500, it means 256KB of redo has
> been written into the current log. The number resets at each log
> switch.
>
> I like to ask why we multiply the value of CPODR_BNO with 512 in
> order to get the redo amount.

Because the number in CPODR_BNO, which I wish I'd never mentioned, is a number of redo log blocks. Log blocks don't actually exist as such... they are merely O/S blocks. And an O/S block is almost invariably 512 bytes in size. So if CPODR_BNO says 1000, that is actually 1000 blocks which equals 512,000 bytes, which equals half a meg of redo.

> Is that process gives the correct amount of redo generated for the
> current transactions?
>
> Is that necessary to perform logswitch manually to findout the redo
> amount as discussed above?

Er, no. You could simply learn how to SQL autotrace. That shows you the amount of redo per statement, which explains the first question I asked in this reply.

*NOBODY* needs to know CPODR_BNO. Unless you are writing a book.

Nobody.

Regards
HJR
> Thanks in Advance.
>
> Juma
Received on Fri Aug 27 2004 - 06:11:35 CDT