Re: Benchmark Data requested

[Richard Huxton <dev(at)archonet(dot)com>]

Matthew wrote:
> On Tue, 5 Feb 2008, Richard Huxton wrote:
> > > Why would you need to lock the table?
> >
> > Because you're not really writing the WAL, which means you can't let 
> > anyone else get their data into any of the blocks you are writing 
> > into. You'd basically want to write the disk blocks then "attach" them 
> > in some way.
>
> So what's wrong with "reserving" the space using the WAL, then everyone 
> else will know. After all, when you write the data to the WAL, you must 
> have an idea of where it is meant to end up. My suggestion is that you 
> go through all the motions of writing the data to the WAL, just without 
> the data bit.

Well, now you're looking at page-level locking for the data blocks, or 
at least something very similar. Not sure what you'd do with indexes 
though - don't see a simple way of avoiding a large lock on a btree index.

If you reserved the space in advance that could work. But you don't know 
how much to reserve until you've copied it in.

You could of course have a set of co-operating processes all 
bulk-loading while maintaining a table-lock outside of the those. It 
feels like things are getting complicated then though.

--
  Richard Huxton
  Archonet Ltd