Hi,
On 2021-05-27 11:07:53 +0900, Michael Paquier wrote:
> This depends on the number of attributes, but I do see an extra 0.5%
> __memmove_avx_unaligned_erms in reform_and_rewrite_tuple() for a
> normal VACUUM FULL with a 1-int-column relation on a perf profile,
> with rewrite_heap_tuple eating most of it as in the past, so that's
> within the noise bandwidth if you measure the runtime.
> What would be the worst case here, a table with one text column made
> of non-NULL still very short values?
I think you need a bunch of columns to see it, like in the benchmark I
just posted - I didn't test any other number of columns than 10 though.
Greetings,
Andres Freund