The post below is the one thing I miss here as being the "only one" (please 
notice the quotes) J programmer in my country.

I sort of miss the face to face discussion. 

r/Alex

-----Original Message-----
From: [email protected] 
[mailto:[email protected]] On Behalf Of Devon McCormick
Sent: Wednesday, May 13, 2009 8:24 PM
To: Programming forum
Subject: Re: [Jprogramming] Strange JDB error.

Oleg -

we spoke about Ken's problem last night at NYCJUG - he's running a 64-bit OS
(XP) on a machine w/8 GB of RAM.

Your idea about generating tables with the same structure and size is a good
one, though.
It sounds like some sort of memory or mapping file corruption is going on.

Regards,

Devon

On Wed, May 13, 2009 at 2:24 AM, Oleg Kobchenko <[email protected]> wrote:

>
> In order to resolve issues like this, they have to be
> easily recreated. Could you generate a simple database
> with fake data but with structure and size similar
> to yours, so that you can reproduce the issue on that
> data?
>
> It is likely that your machine reaches its limits:
> being 32-bit and/or amounts of physical memory.
> This information is also useful.
>
>
>
> > From: "Lettow, Kenneth" <[email protected]>
> >
> > I have been experimenting with JDB for about a month now, and have built
> > up a database that consists of 7 tables with about 50 million records.
> >
> > Recently, after a creating a few versions of the db, I have run into a
> > problem that I cannot figure out.
> >
> > I can initialize the database and import all of the records, and as long
> > as I don't close the db everything works great.
> >
> > Once I close the db and try to reopen it, I am presented with the
> > following error.
> >
> >    db_open DBPATH;DBNAME
> > |domain error: revert
> > |   (id)=:len{.    id~
> >
> > The strange thing is that the db works perfectly as long as I don't
> > close it.
> >
> > I have tried stepping through the revert verb in JDB and found the line
> > that fails.
> >
> > | [0] if. Tran <: Trans do. return. end.
> > >>>>|>[1] len=. tranid (1 i.~ <:) Trans   NB. Line that fails with a
> > domain error.
> > | [2] map=. 'active';Tcolmap
> > | [3] ndx=. I. len < #@". &> map
> > | [4] for_i. ndx do.
> > | [5]   id=. i{map
> > | [6]   (id)=: len {. id~
> > | [7] end.
> > | [8] deleted=: deleted #~ deleted <: Trans
> > | [9] Tran=: Trans
> > | [10] Tdelete=: Tinsert=: ''
> > | [11] writestate''
> >
> > At the point that revert fails the values of Tran, tranid and Trans are
> > as follows.
> >
> >       Trans
> > 14
> >       Tran
> > 25
> >       tranid
> > 80$'6929260$8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8
> > 8 8 8...
> >
> > Any suggestions?
> >
> > Thanks,
> >
> > Ken
> >
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
>
>
>
>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>



-- 
Devon McCormick, CFA
^me^ at acm.
org is my
preferred e-mail
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