Re: freeing bms explicitly

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: Zhihong Yu <zyu@yugabyte.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Amit Kapila <akapila@postgresql.org>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2022-03-23T03:45:27Z
Lists: pgsql-hackers

Attachments

On Tue, Mar 22, 2022 at 3:39 AM Zhihong Yu <zyu@yugabyte.com> wrote:
>
> On Mon, Mar 21, 2022 at 3:05 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>
>> Zhihong Yu <zyu@yugabyte.com> writes:
>> >> I was looking at calls to bms_free() in PG code.
>> >> e.g. src/backend/commands/publicationcmds.c line 362
>> >>      bms_free(bms);
>> >> The above is just an example, there're other calls to bms_free().
>> >> Since the bms is allocated from some execution context, I wonder why this
>> >> call is needed.
>> >>
>> >> When the underlying execution context wraps up, isn't the bms freed ?
>>
>> Yeah, that's kind of pointless --- and the pfree(rfnode) after it is even
>> more pointless, since it'll free only the top node of that expression
>> tree.  Not to mention the string returned by TextDatumGetCString, and
>> whatever might be leaked during the underlying catalog accesses.
>>
>> If we were actually worried about transient space consumption of this
>> function, it'd be necessary to do a lot more than this.  It doesn't
>> look to me like it's worth worrying about though -- it doesn't seem
>> like it could be hit more than once per query in normal cases.
>>
>>                         regards, tom lane
>
>
> Thanks Tom for replying.
>
> What do you think of the following patch ?
>

Your patch looks good to me. I have found one more similar instance in
the same file and changed that as well accordingly. Let me know what
you think of the attached?

-- 
With Regards,
Amit Kapila.

Commits

  1. Remove some useless free calls.