Re: Remove redundant MemoryContextSwith in BeginCopyFrom

On Thu, 20 Jan 2022 at 00:38, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> writes:
>> +1. It looks like a thinko from c532d15d. There's no code in between,
>> so switching to oldcontext doesn't make sense.
>
> Agreed.
>
>> I think we also need to remove MemoryContextSwitchTo(oldcontext); at
>> the end of BeginCopyTo in copyto.c, because we are not changing memory
>> contexts in between.
>
> Hmm, I think it'd be a better idea to remove the one in the middle of
> BeginCopyTo. The code after that is still doing setup of the cstate,
> so the early switch back looks to me like trouble waiting to happen.
>

Agreed

I see you have already push this patch on master (89f059bdf52), why not
remove MemoryContextSwitchTo in the middle of BeginCopyTo in this commit?

--
Regrads,
Japin Li.
ChengDu WenWu Information Technology Co.,Ltd.