Re: strange performance regression between 7.4 and 8.1

On 3/2/07, Florian Weimer <fweimer(at)bfk(dot)de> wrote:
> * Alex Deucher:
>
> > I have noticed a strange performance regression and I'm at a loss as
> > to what's happening. We have a fairly large database (~16 GB).
>
> Sorry for asking, but is this a typo? Do you mean 16 *TB* instead of
> 16 *GB*?
>
> If it's really 16 GB, you should check if it's cheaper to buy more RAM
> than to fiddle with the existing infrastructure.
>

Yes, 16 GB. I'd rather not shell out for more ram, if I'm not even
sure that will help. The new system should be faster, or at least as
fast, so I'd like to sort out what's going on before I buy more ram.

> > however the table structure is almost identical (UTF8 on the new one
> > vs. C on the old).
>
> Locale settings make a huge difference for sorting and LIKE queries.
> We usually use the C locale and SQL_ASCII encoding, mostly for
> performance reasons. (Proper UTF-8 can be enforced through
> constraints if necessary.)
>

I suppose that might be a factor. How much of a performance
difference do you see between utf-8 and C?

Alex