Re: parallel pg_restore - WIP patch

Stefan Kaltenbrunner wrote:
> Tom Lane wrote:
>> Andrew Dunstan <andrew(at)dunslane(dot)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.
>
>
>
>

We don't really need a huge amount of hardwiring as it turns out. Here
is a version of the patch that tries to do what's needed in this area.

cheers

andrew