Re: [HACKERS] Current TODO list - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] Current TODO list
Date
Msg-id 199905210319.XAA16181@candle.pha.pa.us
Whole thread Raw
In response to RE: [HACKERS] Current TODO list  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
Responses Re: [HACKERS] Current TODO list  (Ole Gjerde <gjerde@icebox.org>)
List pgsql-hackers
> > > I wonder that no one but me object to the patch.
> > > It may cause serious results.
> >
> > How?  Why?  In what way?  Details?
> >
> 
> I don't have tables > 1G.
> So I won't be damaged by the patch.
> 
> But I don't understand what Beta is.
> Why isn't such a dangerous fucntion checked and tested
> carefully ?
> 
> For example,the following code is not changed by the patch.
> 
>         if (FileTruncate(v->mdfd_vfd, nblocks * BLCKSZ) < 0)
>                 return -1;
> 
> It never truncate segmented files and there may be cases the
> original file increases its size(ftruncate() increases the size of
> target file if the requested size is longer than the actual size).
> It's not checked and tested and once it occurs I don't know
> what will happen.
> 
> But my anxiety is the use of unlink()(FileNameUnlink()).
> 
> Unlink() is very dangerous.
> Unlink() never remove the target file immediately.and even the
> truncating process doesn't close the files by the patch and so
> unlinked files are still alive for all processes which have already
> opened the files.
> Who checked and tested the influence carefully ?
> 
> I think it's not so easy to implement and check mdtruncate().

OK, I see what you are saying, but the multi-segment problem is on our
list to fix.  Is this risking non-multi-segment cases.  If not, then
let's keep it, and continue improving the multi-segment handling,
because it was pretty bad before, and we need it fixed.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


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