Re: Remove redundant MemoryContextSwith in BeginCopyFrom

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

Cc: Japin Li <japinli@hotmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>

Date: 2022-01-19T16:38:44Z

Lists: pgsql-hackers

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Remove redundant memory context switches in BeginCopyFrom().
- 89f059bdf52c 15.0 landed

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.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.

			regards, tom lane