Re: COPY and Volatile default expressions

On 04/15/2013 06:04 PM, Simon Riggs wrote:
> On 15 April 2013 16:55, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
>>> On 15 April 2013 16:24, David Fetter <david(at)fetter(dot)org> wrote:
>>>> Do you have numbers on this, or ways to gather same? In other words,
>>>> how do we know what resources (time, CPU cycles, disk seeks, etc.) are
>>>> being consumed here?
>>> The multi-insert optimisation for COPY is already there and works well
>>> enough to have been committed.
>> You seem to not have answered the question. Exactly what sort of
>> performance gain might be possible, bearing in mind that anything that
>> invokes a trigger (for instance) is unlikely to be amazingly fast
>> anyway?
> Forgive me, I assumed the list would be familiar with the optimization
> and so be excited by the need for this.
>
> I will implement as a kluge, test and report the results.
Would just declaring nextval() to be a stable function be a good test ?

Hannu
>
> Loading data into a table with a SERIAL or UUID column is the main use
> case, so I'll measure that.
>
> --
> Simon Riggs http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Training & Services
>
>