Re: [HACKERS] 64-bit queryId?

On Thu, Oct 19, 2017 at 1:08 AM, Michael Paquier
<michael.paquier@gmail.com> wrote:
> On Thu, Oct 19, 2017 at 4:12 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Wed, Oct 18, 2017 at 9:20 AM, Julien Rouhaud <rjuju123@gmail.com> wrote:
>>> WIth current pgssHashKey definition, there shouldn't be padding bits,
>>> so it should be safe.  But I wonder if adding an explicit memset() of
>>> the key in pgss_store() could avoid extension authors to have
>>> duplicate entries if they rely on this code, or prevent future issue
>>> in the unlikely case of adding other fields to pgssHashKey.
>>
>> I guess we should probably add additional comment to the definition of
>> pgssHashKey warning of the danger.  I'm OK with adding a memset if
>> somebody can promise me it will get optimized away by all reasonably
>> commonly-used compilers, but I'm not that keen on adding more cycles
>> to protect against a hypothetical danger.
>
> A comment is an adapted answer for me too.

I agree, and I'm perfectly fine with adding a comment around pgssHashKey.

PFA a patch to warn about the danger.

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