Re: [Gnump3d-users] Test the pre-release?

[Stuffed Crust]

On Sun, Sep 03, 2006 at 02:49:17PM +0100, Steve Kemp wrote:
>   OK how does this look?
> 
>     http://www.steve.org.uk/Software/tmp/gnump3d-3.0/bin/gnump3d-indexer
> 
>   [tarball in http://www.steve.org.uk/Software/tmp/]

[[grr, silly editor lost my message...]]

A couple of comments on the indexer:
 
  #
  #  Drop any entries and create the database.  
  #
  purgeDatabase();

I wonder.  Is it faster to drop and re-create the database each 
time, or check for changes and update as needed?  For example:

foreach file in list:
  stat() file.
  look up file in database.
  if present
     if file changed (mtime)
         parse tags
         update row.
   else 
     parse tags
     insert new row

The old tag cache was a simple in-memory lookup, but the new one could 
potentially involve a call to the database for each file. (we could read 
the whole thing into memory to speed things up....).  I don't know what 
kind of overhead that'll involve.

    #
    #  The ID of the previous insertion.
    #
    #  If we used MySQL we could use: $CONFIG{'dbh'}->{mysql_insertid};
    #
    my $id = 0;
    $sth = $CONFIG{'dbh'}->prepare( "SELECT id FROM files WHERE fname=?" );
    $sth->execute( $file );
    my @data = $sth->fetchrow_array();
    $sth->finish();
    $id = $data[0];

There's a generic '$dbh->last_insert_id()' call in modern DBI versions
that would work here; if it returns 'undef' we can use the above code as
a fallback.

Another thing to consider -- SQLite can't handle multiple simultaneous
writers.  If a request happens that doesn't have a tag cached, we
currently look up the tag and add it to the cache.  We could conceivably
have two or more requests do this simultaneously.  I don't know how well
the DBD::SQLite backend will handle the necessary locking. 

 - Solomon
-- 
Solomon Peachy                         pizza at shaftnet dot org         
Melbourne, FL                          ^^ (mail/jabber/gtalk) ^^
Quidquid latine dictum sit, altum viditur.          ICQ: 1318344

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