RE: Perform streaming logical transactions by background workers and parallel apply

On Thur, Sep 8, 2022 at 19:25 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Thu, Sep 8, 2022 at 12:21 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On Mon, Sep 5, 2022 at 6:34 PM houzj(dot)fnst(at)fujitsu(dot)com
> > <houzj(dot)fnst(at)fujitsu(dot)com> wrote:
> > >
> > > Attach the correct patch set this time.
> > >
> >
> > Few comments on v28-0001*:
> > =======================
> >
>
> Some suggestions for comments in v28-0001*

Thanks for your comments and patch!

> 1.
> +/*
> + * Entry for a hash table we use to map from xid to the parallel apply worker
> + * state.
> + */
> +typedef struct ParallelApplyWorkerEntry
>
> Let's change this comment to: "Hash table entry to map xid to the
> parallel apply worker state."
>
> 2.
> +/*
> + * List that stores the information of parallel apply workers that were
> + * started. Newly added worker information will be removed from the list at
> the
> + * end of the transaction when there are enough workers in the pool. Besides,
> + * exited workers will be removed from the list after being detected.
> + */
> +static List *ParallelApplyWorkersList = NIL;
>
> Can we change this to: "A list to maintain the active parallel apply
> workers. The information for the new worker is added to the list after
> successfully launching it. The list entry is removed at the end of the
> transaction if there are already enough workers in the worker pool.
> For more information about the worker pool, see comments atop
> worker.c. We also remove the entry from the list if the worker is
> exited due to some error."
>
> Apart from this, I have added/changed a few other comments in
> v28-0001*. Kindly check the attached, if you are fine with it then
> please include it in the next version.

Improved as suggested.

The new patches were attached in [1].

[1] - https://www.postgresql.org/message-id/OS3PR01MB6275F145878B4A44586C46CE9E499%40OS3PR01MB6275.jpnprd01.prod.outlook.com

Regards,
Wang wei