On 20/08/2018 12:32, Peter Eisentraut wrote:
> On 18/08/2018 23:05, Tom Lane wrote:
>> Possibly we need to be more careful than we are now about whether
>> there's padding at the end of the fixed-size fields ... but just
>> ripping out the code that attempts to deal with that is hardly
>> an improvement.
>
> I don't think the tuple packing issue has to do with the tuple
> descriptor code. The tuple descriptors already use allocations of size
> sizeof(FormData_pg_attribute) (CreateTemplateTupleDesc), just the memcpy
> and memset calls use (potentially) less. That might have saved a few
> bytes for omitting the varlena fields, but I don't think it affects
> alignment correctness. If we, say, added a trailing char field now, the
> only thing this code
[oops]
... the only thing the current code would accomplish is not copying the
last three padding bytes, which might even be slower than copying all four.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
