On Fri, Sep 2, 2022 at 5:25 PM Justin Pryzby <pry...@telsasoft.com> wrote: > > On Tue, Aug 02, 2022 at 12:50:43PM -0500, Justin Pryzby wrote: > > Also, if I understand correctly, this patch seems to assume that nobody is > > connected to the source database. But what's actually enforced is just that > > nobody *else* is connected. Is it any issue that the current DB can be > > used as > > a source? Anyway, both of the above problems are reproducible using a > > different database. > > > > |postgres=# CREATE DATABASE new TEMPLATE postgres STRATEGY wal_log; > > |CREATE DATABASE > > On Thu, Aug 04, 2022 at 05:16:04PM -0500, Justin Pryzby wrote: > > On Thu, Aug 04, 2022 at 06:02:50PM -0400, Tom Lane wrote: > > > The "invalidation" comment bothered me for awhile, but I think it's > > > fine: we know that no other backend can connect to the source DB > > > because we have it locked, > > > > About that - is it any problem that the currently-connected db can be used > > as a > > template? It's no issue for 2-phase commit, because "create database" > > cannot > > run in an txn. > > Would anybody want to comment on this ? > Is it okay that the *current* DB can be used as a template ?
I don't think there should be any problem with that. The main problem could have been that since we are reading the pg_class tuple block by block there could be an issue if someone concurrently modifies the pg_class or there are some tuples that are inserted by the prepared transaction. But in this case, the same backend can not have an open prepared transaction while creating a database and that backend of course can not perform any parallel operation as well. -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com
