So, it may be the machine on which the code is getting executed behind the scene , in the site "https://dbfiddle.uk/"; is playing a key role in the speed, however, the comparative performance of UUID vs sequence should stay the same. So I think, after this test we can safely conclude that if we compare the performance of the UUID(both version-4, version 7) VS sequence. The UUID performs a lot worse as compared to sequence. So unless there exists some strong reason/justification for UUID, we should default use the sequence. Correct me if I'm wrong. And also I understand the cases of multi master replication/sharding etc, may be a factor but other than that I can't think of any scenario where sequences can be used.
On Fri, 3 Feb 2023 at 23:07, Dominique Devienne <ddevie...@gmail.com> wrote: > On Fri, Feb 3, 2023 at 5:48 PM veem v <veema0...@gmail.com> wrote: > >> Actually I did the testing by connecting to "https://dbfiddle.uk/"; >> postgres version -15. >> >> PostgreSQL 15.0 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 >> 20210514 (Red Hat 8.5.0-10), 64-bit >> >> Am I doing it wrong, please confirm? >> >> > No clue. But even SQLite can generate 1M uuid (16 bytes random blobs are > equivalent) is 1/3 of the time, so 30x faster. > So your timings of generating 100K uuids and counting them seems way too > slow to me. --DD > > sqlite> select count(randomblob(16)) from generate_series(1,1000*1000); > QUERY PLAN > `--SCAN generate_series VIRTUAL TABLE INDEX 3: > addr opcode p1 p2 p3 p4 p5 comment > ---- ------------- ---- ---- ---- ------------- -- ------------- > 0 Init 0 15 0 0 Start at 15 > 1 Null 0 1 1 0 r[1..1]=NULL > 2 VOpen 0 0 0 vtab:274D3E0 0 > 3 Integer 1 4 0 0 r[4]=1 > 4 Multiply 6 6 5 0 r[5]=r[6]*r[6] > 5 Integer 3 2 0 0 r[2]=3 > 6 Integer 2 3 0 0 r[3]=2 > 7 VFilter 0 11 2 0 iplan=r[2] > zplan='' > 8 Function 1 8 7 randomblob(1) 0 r[7]=func(r[8]) > 9 AggStep 0 7 1 count(1) 1 accum=r[1] > step(r[7]) > 10 VNext 0 8 0 0 > 11 AggFinal 1 1 0 count(1) 0 accum=r[1] N=1 > 12 Copy 1 9 0 0 r[9]=r[1] > 13 ResultRow 9 1 0 0 output=r[9] > 14 Halt 0 0 0 0 > 15 Transaction 0 0 1 0 1 usesStmtJournal=0 > 16 Integer 1000 6 0 0 r[6]=1000 > 17 Integer 16 8 0 0 r[8]=16 > 18 Goto 0 1 0 0 > ┌───────────────────────┐ > │ count(randomblob(16)) │ > ├───────────────────────┤ > │ 1000000 │ > └───────────────────────┘ > Run Time: real 0.278 user 0.250000 sys 0.000000 > > >> On Fri, 3 Feb 2023 at 21:28, Dominique Devienne <ddevie...@gmail.com> >> wrote: >> >>> 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: >>> >>
