Re: [Pytables-users] my indexes go poof

[Francesc A. <fa...@ca...>]

Hi,

I'm afraid you have hitten a known bug. Please, try with a recent
snapshot available in:

http://www.carabos.com/downloads/pytables/snapshots/

and tell me if this works for you.

Regards,

A Dilluns 14 Febrer 2005 09:43, damon fasching va escriure:
> Hi,
>
> I'm having some trouble generating an index on a Table
> column.  Actually, I think the index is created, but I
> can't access it the next time I open the file.
>
> I have a job which creates a very simple pytables
> file.  Just one group with 4 pretty simple tables.  I
> dump a bunch of data into the tables.  There is one
> column on which I will usually select, so I would like
> to create an index on this column.  In order to get
> experience with pytables, I've done two runs over the
> same input data.  In the first run I did not index any
> columns.  In the second run I indexed the column of
> interest.  I'm certain the index was generated because
> a) I created the IsDescription class with indexed=3D1
> for that column (very straightforward), b) that was
> the only difference between the scripts for the two
> runs and the output file for the indexed run was about
> 20% larger than the output file with no index.
>
> When I access data (in a later Python session), using
> the where operator to select on the indexed column,
> the access is pretty slow, and in fact, it is SLOWER
> when I run using the file with the index.  I'm pretty
> sure that the index is in the file (because the file
> is bigger) but it is not seen when I open the file.
> If I print the file (by typing the symbol returned by
> openFile()) none of the columns are indicated as
> having been indexed.  Yet, if I print the file during
> the session in which it was originally created, the
> column which I asked to be indexed is indeed indicated
> as so.
>
> I reproduced the error in an interactive session with
> a simpler file structure.  I have attached the screen
> dump of that session as 'pytables.indextest.session'.
> I've added a few annotations to this file, but it
> should be pretty easy to see the problem.  I've
> attached another file, 'pytables.install.session'
> which is a screendump of the session where I built
> installed and tested pytables.  From there you can see
> the details of my configuration.  I think everything
> is in order.
>
> So, a lot of words, but a single question.  What
> happened to my index...and how can I make it not
> happend?
>
> Thanks!
>   Damon
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com

=2D-=20
>qo<   Francesc Altet =A0 =A0 http://www.carabos.com/
V =A0V   C=E1rabos Coop. V. =A0=A0Enjoy Data
 ""