AW: UUID vs. Sequential ID as Primary

From: <ahmed.fikri_at_t-online.de>
Date: Sat, 13 Apr 2024 16:10:10 +0200 (CEST)
Message-ID: <1713017410268.215712.d0750801366333322f8c9ed79af7f3540df2f280_at_spica.telekom.de>



 

I didn't notice the thing with 37 MB (thanks :-)). And it is the same for Sequence that uses Long (8 Bytes). This give me a reason to conduct the test with Oracle 21 and see if we get the same behaviour (as we are working with this version).  

I must also admit that my tests are initially rudimentary (And it's done in my spare time, unfortunately not within the project I'm currently working on). I am simply trying to understand why many teams in our organization exclusively use UUIDs (and also in many other organizations). But of course, the whole thing needs to be examined more closely. My hope was that someone from this list would state whether it is a bad or good practice to work with UUIDs, providing the reason.  

When I worked on projects where only PL/SQL was used, this issue was not questioned.  

Regards
Ahmed          

-----Original-Nachricht-----
Betreff: Re: UUID vs. Sequential ID as Primary Datum: 2024-04-13T15:35:25+0200
Von: "Jonathan Lewis" <jlewisoracle_at_gmail.com> An: "list, oracle" <oracle-l_at_freelists.org>        

I raised the concurrency issue for two reasons:  

  1. The sequence was slower by 2.3 seconds on the creation of ids, but was faster by 9 seconds on saving data. That made sequences overall a better bet (despite your comment about uuid outperforming sequences) on a pure performance point.
  2. The index size for UUID was 37MB - but a UUID is only 16 bytes, so the index was more than double the size of the values it was storing. From an Oracle perspective that could have been a side effect of the randomness of the data (plus a component to do with row pointers) - but the size of the Oracle index was as I would have expected for a serial test of sequence values, and therefore seriously undersized for a test of reasonable concurrency. SO ... this led me to the point of wondering (in my ignorance) whether Postgres was basically behaving badly even in a serial test with a risk of getting MUCH worse in a concurrent test.

I appreciate that you have a stated requirement to see the ID values before they are used on the insert - in which case the locally generated UUID is clearly the sensible option (without doing any testing) because a round-trip to the database to get the server to generate a UUID has to be more time-consuming than generating the UUID locally; but you still ought to test whether the local option turns into a total disaster for saving and retrieval at your expected level of concurrency.  

Regards
Jonathan Lewis    

On Sat, 13 Apr 2024 at 14:10, ahmed.fikri_at_t-online.de
<mailto:ahmed.fikri_at_t-online.de> <ahmed.fikri_at_t-online.de
<mailto:ahmed.fikri_at_t-online.de> > wrote:
  If the UUID method already outperforms sequences in a single session,   then the performance of the sequence method will be even worse in   multiple concurrent sessions. Additionally, UUIDs are generated on the   client side. Therefore, I believe that conducting the test with only one   session is sufficient. My aim was simply to confirm that UUIDs are a   better choice for microservice architecture    

  Regards
  Ahmed              



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Received on Sat Apr 13 2024 - 16:10:10 CEST

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