Re: Parallel copy

On Wed, Oct 21, 2020 at 3:50 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Wed, Oct 21, 2020 at 3:19 PM Bharath Rupireddy
> <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
> >
> >
> > 9. Instead of calling CopyStringToSharedMemory() for each string
> > variable, can't we just create a linked list of all the strings that
> > need to be copied into shm and call CopyStringToSharedMemory() only
> > once? We could avoid 5 function calls?
> >
>
> If we want to avoid different function calls then can't we just store
> all these strings in a local structure and use it? That might improve
> the other parts of code as well where we are using these as individual
> parameters.
>

I have made one structure SerializedListToStrCState to store all the
variables. The rest of the common variables is directly copied from &
into cstate.

> > 10. Similar to above comment: can we fill all the required
> > cstate->variables inside the function CopyNodeFromSharedMemory() and
> > call it only once? In each worker we could save overhead of 5 function
> > calls.
> >
>
> Yeah, that makes sense.
>

I feel keeping it this way makes the code more readable, and also this
is not in a performance intensive tight loop. I'm retaining the
change as is unless we feel this will make an impact.

This is addressed in v9 patch shared at [1].
[1] - https://www.postgresql.org/message-id/CALDaNm1cAONkFDN6K72DSiRpgqNGvwxQL7TjEiHZ58opnp9VoA@mail.gmail.com

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com