Re: 15 pg_upgrade with -j

On 5/22/23 5:42 PM, Tom Lane wrote:
> Jeff Ross<jross(at)openvistas(dot)net> writes:
>> On 5/22/23 5:24 PM, Adrian Klaver wrote:
>>> So is the 1400G mostly in one database in the cluster?
>> Yes, one big database with about 80 schemas and several other smaller
>> databases so -j should help, right?
> AFAICT from a quick look at the code, you won't get any meaningful
> parallelism unless you have several large DBs and/or several large
> tablespaces. It looks like the assumption was that issuing link()
> requests in parallel wouldn't help much but just swamp your disk
> if they're all on the same filesystem. Maybe that could use
> rethinking, not sure.
>
> regards, tom lane
>
>
Thanks Tom.  These are all smokingly fast SSDs so it would be
interesting to see how well they'd hold up under that load.

Jeff