Re: freeing bms explicitly

From: Zhihong Yu <zyu(at)yugabyte(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: akapila(at)postgresql(dot)org, PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: freeing bms explicitly
Date: 2022-03-21 22:13:18
Message-ID: CALNJ-vR3dVBq3ARG0Hj1Q5vQB37OpabjeiW65yCxn7x5TwpeyQ@mail.gmail.com
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On Mon, Mar 21, 2022 at 3:05 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Zhihong Yu <zyu(at)yugabyte(dot)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 ?

Cheers

Attachment Content-Type Size
rfcolumn-free.patch application/octet-stream 534 bytes

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