[Xapian-discuss] Ticket #342: Omega: Add option to avoid reindexing unchanged files

[James Aylett]

On Thu, May 21, 2009 at 03:49:51AM +0100, Olly Betts wrote:

> > Can we get the inode cheaply? Where supported, I can't think of
> > many practical situations where it would change but the contents not.
> 
> You can get the inode number from stat() on platforms and filesystems
> where "inode" is a meaningful concept.  But moving a large tree of files
> to a new partition (e.g. restoring them from backup after a disk failure)
> would then force a full reindex, which is unhelpful.

That's true, which is unhelpful. There's basically no good way of
doing it that fits everything, of course :-/

> Also the inode for the "old" file isn't currently stored (and isn't
> useful for other purposes), so there's extra I/O and diskspace overhead.

Sure.

> And again, webservers don't check the inode for "If-Modified-Since"...

No, but many do for ETag (If-None-Match); it's the default in Apache I
believe. It's not a particularly *good* default, but that's another
issue entirely.

J

-- 
  James Aylett

  talktorex.co.uk - xapian.org - uncertaintydivision.org