MIME-Version: 1.0
References: <CA+FnnTyR9AoJx-3zuvgudeYmUTiNcfpAucUh0ZTcs=Ajy49qVA@mail.gmail.com>
 <CAKFQuwZKp_FWZ0mi9H8th+fh70KeoV=4_6uB40TvQ9r1Q04UhA@mail.gmail.com>
In-Reply-To: <CAKFQuwZKp_FWZ0mi9H8th+fh70KeoV=4_6uB40TvQ9r1Q04UhA@mail.gmail.com>
From: Igor Korot <ikorot01@gmail.com>
Date: Sat, 26 Apr 2025 23:58:00 -0500
Message-ID: <CA+FnnTxb=A9F4qw1oN6noatGC0UtE6OUgDe+K-J08YFUaOfJXQ@mail.gmail.com>
Subject: Re: How to properly fix memory leak
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: "pgsql-generallists.postgresql.org" <pgsql-general@lists.postgresql.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: <https://www.postgresql.org/message-id/CA%2BFnnTxb%3DA9F4qw1oN6noatGC0UtE6OUgDe%2BK-J08YFUaOfJXQ%40mail.gmail.com>
Precedence: bulk

David et al,

On Fri, Apr 25, 2025 at 10:48=E2=80=AFPM David G. Johnston
<david.g.johnston@gmail.com> wrote:
>
> On Friday, April 25, 2025, Igor Korot <ikorot01@gmail.com> wrote:
>>
>>
>>         for( int i =3D 0; i < PQntuples( res ); i++ )
>>         {
>>             auto temp1 =3D m_pimpl->m_myconv.from_bytes( PQgetvalue(
>> res, i, 1 ) );
>>             m_tablespaces.push_back( temp1 );
>>         } // this line gives a leak according to VLD
>>     }
>>     PQclear( res );
>>     return result;
>> [/code]
>>
>> I ran this code on MSVC 2017  with VLD and according to the VLD report I=
 have
>> a memory leak on the line indicated.
>
>
> Seems like a false positive.

Looks like it is false positive.

I ran the code under valgrind and there I didn't get
such a leak.
I did however get a different issues which I fixed.
But even after moving the fixes ober to Windows and trying
to run it - I still see that.

For now I put this to bed as it is not an issue on Linux.

Thank you.

>
>>
>>
>> Should I call PQclear() on every iteration of the loop?
>
>
> Would make processing more than a single row impossible if you throw away=
 the result after processing one row.
>
> David J.
>