Re: why postgresql over other RDBMS

[PFC <lists(at)peufeu(dot)com>]

On Thu, 31 May 2007 23:36:32 +0200, PFC <lists(at)peufeu(dot)com> wrote:

> On Thu, 31 May 2007 22:20:09 +0200, Vivek Khera <vivek(at)khera(dot)org> wrote:
>
> > On May 25, 2007, at 5:28 PM, Tom Lane wrote:
> >
> > > That's true at the level of DDL operations, but AFAIK we could
> > > parallelize table-loading and index-creation steps pretty effectively
> > > --- and that's where all the time goes.
> >
> > I would be happy with parallel builds of the indexes of a given table.   
> > That way you have just one scan of the whole table to build all its  
> > indexes.

	Just did a test :

	- large table (does not fit in RAM)
	- rows with text column (forum posts)
	- about 700K rows

Time to create 3 indexes : 61 s
Time to create 3 indexes with 3 simultaneous connections : 22 s

	That's what you would expect...
	vmstat shows the data is really loaded from disk, once with the 3  
threads, 3 times when indexes are created one at a time.