RE: [PATCH][BUG FIX] Unsafe access pointers.

From: Ranier Vilela <ranier_gyn(at)hotmail(dot)com>
To: "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: RE: [PATCH][BUG FIX] Unsafe access pointers.
Date: 2019-11-15 12:24:04
Message-ID: MN2PR18MB292780E1F07F3C4E7FE9D63DE3700@MN2PR18MB2927.namprd18.prod.outlook.com
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Hi,
Thank you for the explanation.

Best regards.
Ranier Vilela
________________________________________
De: Daniel Gustafsson <daniel(at)yesql(dot)se>
Enviado: sexta-feira, 15 de novembro de 2019 11:58
Para: Ranier Vilela
Cc: pgsql-hackers(at)lists(dot)postgresql(dot)org
Assunto: Re: [PATCH][BUG FIX] Unsafe access pointers.

> On 15 Nov 2019, at 12:25, Ranier Vilela <ranier_gyn(at)hotmail(dot)com> wrote:

> It's probably not happening, but it can happen, I think.

I don't think it can, given how elog() works.

> - if (!HeapTupleIsValid(classtup))
> + if (!HeapTupleIsValid(classtup)) {
> elog(ERROR, "cache lookup failed for operator class %u", opclassoid);
> + return false;

elog or ereport with a severity of ERROR or higher will never return.

> - if (!HeapTupleIsValid(familytup))
> + if (!HeapTupleIsValid(familytup)) {
> elog(ERROR, "cache lookup failed for operator family %u", opfamilyoid);
> + ReleaseSysCache(classtup);
> + return false;
> + }

Not only will elog(ERROR ..) not return to run this, the errorhandling
machinery will automatically release resources and clean up.

cheers ./daniel

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