Copying the list... ---------- Forwarded message --------- From: Dominique Devienne <ddevie...@gmail.com> Date: Fri, Feb 3, 2023 at 4:57 PM Subject: Re: Sequence vs UUID To: veem v <veema0...@gmail.com>
On Thu, Feb 2, 2023 at 8:47 PM veem v <veema0...@gmail.com> wrote: > Tested the UUIDv7 generator for postgres as below. > With regards to performance , It's still way behind the sequence. [...] > explain analyze select count(nextval('myseq') ) from > generate_series(1,100000); > Execution Time: 59.687 ms > > explain analyze select count(gen_random_uuid()) from > generate_series(1,100'000); > Execution Time: 904.868 ms > > explain analyze select count(uuid_generate_v7()) from > generate_series(1,100000); > Execution Time: 1711.187 ms > Something's off regarding Guid generations IMHO... You generate 100K Guids in ~1s. While we generate (in C++, Windows Release, using Boost) 16M of them in +/- the same time: Enabling Performance tests >>> >> > generate 16'000'000 guids in 0.980s (user: 0.984s) 12 MB >>> >> generate 16'000'000 guids in parallel on 4 CPUs in 0.309s (user: 1.188s) >>> 12 MB >>> >> That's 2 orders of magnitude faster. Sure there's some overhead from the SQL, but still. Something seems fishy. And that's on a 2.5y old desktop. --DD