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

On Fri, Sep 9, 2022 at 12:32 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
>
> 29. src/backend/replication/logical/worker.c - TransactionApplyAction
>
> /*
> * What action to take for the transaction.
> *
> * TA_APPLY_IN_LEADER_WORKER means that we are in the leader apply worker and
> * changes of the transaction are applied directly in the worker.
> *
> * TA_SERIALIZE_TO_FILE means that we are in leader apply worker and changes
> * are written to temporary files and then applied when the final commit
> * arrives.
> *
> * TA_APPLY_IN_PARALLEL_WORKER means that we are in the parallel apply worker
> * and changes of the transaction are applied directly in the worker.
> *
> * TA_SEND_TO_PARALLEL_WORKER means that we are in the leader apply worker and
> * need to send the changes to the parallel apply worker.
> */
> typedef enum
> {
> /* The action for non-streaming transactions. */
> TA_APPLY_IN_LEADER_WORKER,
>
> /* Actions for streaming transactions. */
> TA_SERIALIZE_TO_FILE,
> TA_APPLY_IN_PARALLEL_WORKER,
> TA_SEND_TO_PARALLEL_WORKER
> } TransactionApplyAction;
>
> ~
>
> 29a.
> I think if you change all those enum names slightly (e.g. like below)
> then they can be more self-explanatory:
>
> TA_NOT_STREAMING_LEADER_APPLY
> TA_STREAMING_LEADER_SERIALIZE
> TA_STREAMING_LEADER_SEND_TO_PARALLEL
> TA_STREAMING_PARALLEL_APPLY
>
> ~
>

I also think we can improve naming but adding streaming in the names
makes them slightly difficult to read. As you have suggested, it will
be better to add comments for streaming and non-streaming cases. How
about naming them as below:

typedef enum
{
TRANS_LEADER_APPLY
TRANS_LEADER_SERIALIZE
TRANS_LEADER_SEND_TO_PARALLEL
TRANS_PARALLEL_APPLY
} TransApplyAction;

--
With Regards,
Amit Kapila.