Re: 15 pg_upgrade with -j - Mailing list pgsql-general

From Tom Lane
Subject Re: 15 pg_upgrade with -j
Date
Msg-id 774330.1684798934@sss.pgh.pa.us
Whole thread Raw
In response to Re: 15 pg_upgrade with -j  (Jeff Ross <jross@openvistas.net>)
Responses Re: 15 pg_upgrade with -j  (Ron <ronljohnsonjr@gmail.com>)
Re: 15 pg_upgrade with -j  (Jeff Ross <jross@openvistas.net>)
List pgsql-general
Jeff Ross <jross@openvistas.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



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