Re: parallel pg_restore - WIP patch

Dimitri Fontaine wrote:
> Le lundi 29 septembre 2008, Tom Lane a écrit :
>
>> * 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.
>>
>
> Well, it seems to me that currently the FK needs in term of existing indexes
> and locks, and some other object lock needs, are all hardwired. Is it even
> safe to consider having the locks needed for certain commands not be
> hardwired?
>
> Provided I'm not all wrong here, I don't see how having something more
> flexible at restore time than at build time is a win. The drawback is that
> whenever you change a lock need in commands, you have to remember teaching
> pg_restore about it too.
>
> So my vote here is in favor of hardwired knowledge of pg_restore, matching
> target server code assumptions and needs.
>
>

Well, I've had to use some knowledge of various item types already, and
I have been trying not to disturb pg_dump also, so I'm inclined to build
this knowledge into pg_restore.

ISTM that "things that will have lock conflicts" are different and more
target version dependent than "things that logically depend on other
things", so we can still rely on pg_dump to some extent to provide the
latter while building the former at restore time.

cheers

andrew