Re: How much expensive are row level statistics?

On Mon, Dec 12, 2005 at 10:23:42AM -0300, Alvaro Herrera wrote:
> Michael Fuhr wrote:
> > The cost depends on your usage patterns. I did tests with one of
> > my applications and saw no significant performance difference for
> > simple selects, but a series of insert/update/delete operations ran
> > about 30% slower when block- and row-level statistics were enabled
> > versus when the statistics collector was disabled.
>
> This series of i/u/d operations ran with no sleep in between, right?
> I wouldn't expect a normal OLTP operation to be like this. (If it is
> you have a serious shortage of hardware ...)

There's no sleeping but there is some client-side processing between
groups of i/u/d operations. As I mentioned in another message, the
application reads a chunk of data from a stream, does a few i/u/d
operations to update the database, and repeats several thousand times.

The hardware is old but it's adequate for this application. What
kind of overhead would you expect?

--
Michael Fuhr