Skip site navigation (1) Skip section navigation (2)

Re: Small fix for inv_getsize

From: Denis Perchine <dyp(at)perchine(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-patches(at)postgresql(dot)org
Subject: Re: Small fix for inv_getsize
Date: 2000-11-02 17:02:23
Message-ID: 0011022302230F.31936@dyp.perchine.com (view raw or flat)
Thread:
Lists: pgsql-patches
> > Just realized that inv_getsize is a little bit wrong :-)). It just get
> > the first page, not last
> > Here is the patch which will fix the behavior.
>
> No it doesn't; it's a loop, and your patch will change nothing.  Your
> original version tried to stop after fetching one tuple, which was
> wrong because of visibility considerations.
>
> Now that I think about it, this code could do a two-key scan backwards
> and stop after finding the first (last) valid tuple, but that's more
> than a one-line change.

Actual logic is to find the maximum of pageno, for specified oid.
I do index scan on 2-keys index, specifying only one key as constraint...
If I do index scan forward I will get the smallest pageno first...
Otherwise I get the highest pageno... And this is what I want...
Or I get something wrong? Isn't this how order by on index is done?

-- 
Sincerely Yours,
Denis Perchine

----------------------------------
E-Mail: dyp(at)perchine(dot)com
HomePage: http://www.perchine.com/dyp/
FidoNet: 2:5000/120.5
----------------------------------

In response to

Responses

pgsql-patches by date

Next:From: Tom LaneDate: 2000-11-02 17:32:38
Subject: Re: Small fix for inv_getsize
Previous:From: Tom LaneDate: 2000-11-02 16:49:38
Subject: Re: Small fix for inv_getsize

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group