Re: parallel pg_restore - WIP patch

Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
>> Tom Lane wrote:
>>> Um, FKs could conflict with each other too, so that by itself isn't
>>> gonna fix anything.
> 
>> Good point. Looks like we'll need to make a list of "can't run in 
>> parallel with" items as well as strict dependencies.
> 
> Yeah, I was just thinking about that.  The current archive format
> doesn't really carry enough information for this.  I think there
> are two basic solutions we could adopt:
> 
> * Extend the archive format to provide some indication that "restoring
> this object requires exclusive access to these dependencies".
> 
> * Hardwire knowledge into pg_restore that certain types of objects
> require exclusive access to their dependencies.
> 
> The former seems more flexible, as well as more in tune with the basic
> design assumption that pg_restore shouldn't have a lot of knowledge
> about individual archive object types.  But it would mean that you
> couldn't use parallel restore with any pre-8.4 dumps.  In the long run
> that's no big deal, but in the short run it's annoying.

hmm not sure how much of a problem that really is - we usually recommend 
to use the pg_dump version of the target database anyway.




Stefan