Re: POC: postgres_fdw insert batching

On Tue, Jan 19, 2021 at 2:06 PM tsunakawa(dot)takay(at)fujitsu(dot)com
<tsunakawa(dot)takay(at)fujitsu(dot)com> wrote:
> From: Amit Langote <amitlangote09(at)gmail(dot)com>
> > I apologize in advance for being maybe overly pedantic, but I noticed
> > that, in ExecInitModifyTable(), you decided to place the call outside
> > the loop that goes over resultRelations (shown below), although my
> > intent was to ask to place it next to the BeginForeignModify() in that
> > loop.
>
> Actually, I tried to do it (adding the GetModifyBatchSize() call after BeginForeignModify()), but it failed. Because postgresfdwGetModifyBatchSize() wants to know if RETURNING is specified, and ResultRelInfo->projectReturning is created after the above part. Considering the context where GetModifyBatchSize() implementations may want to know the environment, I placed the call as late as possible in the initialization phase. As for the future(?) multi-target DML statements, I think we can change this together with other many(?) parts that assume a single target table.

Okay, sometime later then.

I wasn't sure if bringing it up here would be appropriate, but there's
a patch by me to refactor ModfiyTable result relation allocation that
will have to remember to move this code along to an appropriate place
[1]. Thanks for the tip about the dependency on how RETURNING is
handled. I will remember it when rebasing my patch over this.

--
Amit Langote
EDB: http://www.enterprisedb.com

[1] https://commitfest.postgresql.org/31/2621/