Re: how to test locks

From: Andy <enzoweb_at_hotmail.com>
Date: 23 Jan 2002 15:01:35 -0800
Message-ID: <8d4033cd.0201231501.2f4e1cc1@posting.google.com>

If you have access to Metalink, there is a good faq on locking.

Go to the Advanced Search and put this in the search field:

Note:15476.1

and click on the "Doc ID" thingy.

mngong_at_yahoo.com (michael ngong) wrote in message news:<ecf365d5.0201231046.542aef6c_at_posting.google.com>...

> "Stephen B" <stephen.bell_at_cgi.ca> wrote in message news:<Coz38.13816$KC1.2314744_at_news20.bellglobal.com>...

> > Oh yeah...hardly a day goes by when I don't do that :)
> >
> > "Mladen Gogala" <mgogala_at_earthlink.net> wrote in message
> > news:pan.2002.01.23.03.00.36.167637.1171_at_earthlink.net...
> > > On Wed, 23 Jan 2002 02:15:26 -0500, Thomas wrote:
> > >
> > > > Hi everybody,
> > > >
> > > > I have a simple question. How can i test weather a record in a table is
> > > > locked by another user without causing another lock.
> > > >
> > > > regards
> > > > thomas
> > >
> > >
> > > That is very simple and I'm sure that the most of us here do that every

>  day:


> > > you find the database block for that record (rowid contains file and block

> > > id), dump the block from oradebug and see whether the row header contains

> > > the pointer to a valid ITL in that block. The very first byte of the row

> > > header is the offset into the ITL table. ITLs are 23 bytes in size and

> > > contain a XID of the transaction that is interested in the block. After

> > > you do that, ask yourself whether the obtained information was worth the

> > > trouble. Oh yes, and exact descriptions on the database blocks can be

> > > obtained only in the Scott Gosset's  "top gun" class.

> > > Oh, did I forget to mention that you have to check whether the block is in

> > > SGA (v$bh) and if it is, then you have to look there. ITLs in the disk

> > > block may contain invalid information and be scheduled for "delayed
> > > cleanup". It's a very simple thing indeed.

> 
> Could we make our answers a little bit clear and simpler for
>  those who may really need  our help.?
> Thanks

Received on Wed Jan 23 2002 - 17:01:35 CST