Re: WIP patch for parallel pg_dump

On 12/06/2010 10:40 AM, Tom Lane wrote:
> Robert Haas<robertmhaas@gmail.com>  writes:
>> On Mon, Dec 6, 2010 at 9:45 AM, Heikki Linnakangas
>> <heikki.linnakangas@enterprisedb.com>  wrote:
>>> Well, then you need some sort of cross-backend communication, which is
>>> always a bit clumsy.
>> A temp file seems quite sufficient, and not at all difficult.
> "Not at all difficult" is nonsense.  To do that, you need to invent some
> mechanism for sender and receivers to identify which temp file they want
> to use, and you need to think of some way to clean up the files when the
> client forgets to tell you to do so.  That's going to be at least as
> ugly as anything else.  And I think it's unproven that this approach
> would be security-hole-free either.  For instance, what about some other
> session overwriting pg_dump's snapshot temp file?
>
>         

Yeah. I'm still not convinced that using shared memory is a bad way to 
pass these around. Surely we're not talking about large numbers of them. 
What am I missing here?

cheers

andrew