Re: Concatenate performance question

On 03/12/06, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> "Michael Guyver" <kenevel(at)googlemail(dot)com> writes:
> > ... Running the array_append version is faster by at least one order of
> > magnitude in these examples.
>
> Really? I see only about a 50% advantage (155 msec vs 105 msec) in both
> 8.1 and 8.2. What PG version are you running? What database encoding
> are you using?

Hi Tom,

Thanks for taking the time to have a look at this. Perhaps I
overstated the case when I said an order of magnitude :¬O That said,
however, I'm fairly sure that the difference was more than you've
seen.

The hardware may indeed have been a factor - I was running psql 8.1 on
a laptop (AMD 64 3200, 1GB RAM, 5400rpm HDD) so the difference in
performance may have been more pronounced. I will check the figures
when I next get to my laptop at home, but I'm currently doing silly
hours at work for the release we have this week.

From some fairly unscientific bodging I've found that a mixture of the
two is the most performant, as I mentioned in a previous post.
Incidentally using a RETURN NEXT statement where I previously employed
an array_append performed as well if not slightly better than my
previous approach. Any thoughts?

Cheers

Michael