View Single Post

   
  #7 (permalink)  
Old 04-12-2008, 03:37 AM
Andreas Pflug
 
Posts: n/a
Default Re: Inefficient bytea escaping?

Tom Lane wrote:
> Andreas Pflug <pgadmin@pse-consulting.de> writes:
>
>>Here are the results, with the copy patch:

>
>
>>psql \copy 1.4 GB from table, binary:
>>8.0 8.1 8.2dev
>>36s 34s 36s

>
>
>>psql \copy 6.6 GB from table, std:
>>8.0 8.1 8.2dev
>>375s 362s 290s (second:283s)

>
>
> Hmph. There's something strange going on on your platform (what is it
> anyway?)


Debian 2.6.26.

> It's interesting (and surprising) that the runtime is
> actually less for psql \copy than for server COPY. This is a dual Xeon
> machine, maybe the frontend copy provides more scope to use both CPUs?


The dual CPU explanation sounds reasonable, but I found the same
tendency on a single 3GHz (HT disabled).
Strange observation using top:
user >90%, sys <10%, idle+wait 0% but only postmaster consumes cpu,
showing 35%, the rest neglectable.
>
> It would be interesting to see what's happening on your machine with
> oprofile or equivalent.


I'll investigate further, trying to find the missing CPU.

Regards,
Andreas

---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?

http://archives.postgresql.org

Reply With Quote