MIME-Version: 1.0
References: <AM9P191MB1286DAAE95E27A8FB79376D5B0002@AM9P191MB1286.EURP191.PROD.OUTLOOK.COM>
In-Reply-To: <AM9P191MB1286DAAE95E27A8FB79376D5B0002@AM9P191MB1286.EURP191.PROD.OUTLOOK.COM>
From: Dominique Devienne <ddevienne@gmail.com>
Date: Mon, 8 Apr 2024 18:40:07 +0200
Message-ID: <CAFCRh--GRPHBhdgrnQOMRves3hKr==S90Mkq7RmnRgjChX8gVw@mail.gmail.com>
Subject: Re: prepared statement "cu1" already exists (but it does not)
To: Sebastien Flaesch <sebastien.flaesch@4js.com>
Cc: pgsql-general <pgsql-general@lists.postgresql.org>
Content-Type: multipart/alternative; boundary="000000000000efc2260615987536"
Archived-At: <https://www.postgresql.org/message-id/CAFCRh--GRPHBhdgrnQOMRves3hKr%3D%3DS90Mkq7RmnRgjChX8gVw%40mail.gmail.com>
Precedence: bulk

--000000000000efc2260615987536
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Mon, Apr 8, 2024 at 5:31=E2=80=AFPM Sebastien Flaesch <sebastien.flaesch=
@4js.com>
wrote:

> I understand when this can happen, but in fact I do de-allocate prepared
> statements when I should.
>

We've run into similar issues. We're in C++, and with RAII deallocate
resources (Prepared Statements, Cursors) in Dtors.
But as you saw, when a TX is KO, any Dtor trying to release resources via
libpq will fail. So what I do it record those
resources (stmt and cursor names basically) on the Connection (in our
wrapper), and will release them at the first opportunity,
once the TX has rolled back for example. FWIW.

OTOH, we tend not to reuse names, generating random ones, since when using
our wrappers, the name is an impl details basically.
We also tend to prepare outside transactions, so can't answer your question
on whether prepared statements within TX are "scoped" or not. --DD

--000000000000efc2260615987536
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div dir=3D"ltr">On Mon, Apr 8, 2024 at 5:31=E2=80=AFPM Se=
bastien Flaesch &lt;<a href=3D"mailto:sebastien.flaesch@4js.com">sebastien.=
flaesch@4js.com</a>&gt; wrote:<br></div><div class=3D"gmail_quote"><blockqu=
ote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px=
 solid rgb(204,204,204);padding-left:1ex"><div class=3D"msg-874723768619361=
4033">


<div dir=3D"ltr">
<div style=3D"font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Cali=
bri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"><span style=3D"fo=
nt-size:12pt">I understand when this can happen, but in fact I do de-alloca=
te prepared statements when I should.</span><br></div></div></div></blockqu=
ote><div><br></div><div>We&#39;ve run into similar issues. We&#39;re in C++=
, and with RAII deallocate resources (Prepared Statements, Cursors) in Dtor=
s.</div><div>But as you saw, when a TX is KO, any Dtor trying to release re=
sources via libpq will fail. So what I do it record those</div><div>resourc=
es (stmt and cursor names basically) on the Connection (in our wrapper), an=
d will release them at the first opportunity,</div><div>once the TX has rol=
led back for example. FWIW.</div><div><br></div><div>OTOH, we tend not to r=
euse names, generating random ones, since when using our wrappers, the name=
 is an impl details basically.</div><div>We also tend to prepare outside tr=
ansactions, so can&#39;t answer your question on whether prepared statement=
s within TX are &quot;scoped&quot; or not. --DD</div></div></div>

--000000000000efc2260615987536--