Re: Sequence vs UUID

On 1/26/23 15:55, Erik Wienhold wrote:
>> On 26/01/2023 20:17 CET veem v <veema0000@gmail.com> wrote:
>>
>> Hello, We were trying to understand whether we should use UUID or Sequence in
>> general for primary keys. In many of the blogs (one is below) across multiple
>> databases, I saw over the internet and all are mostly stating the sequence is
>> better as compared to UUID. But I think in the case of concurrent data load
>> scenarios UUID will spread the contention point whereas sequence can be a
>> single point of contention.
>>
>> So we want to understand from experts here, if there are any clear rules
>> available or if we have any pros vs cons list available for each of those to
>> understand the exact scenario in which we should go for one over other?
>> Basically I wanted to see if we can perform some test on sample data to see
>> the percentage of overhead on read and write performances of the query in
>> presence of UUID VS Sequence to draw some conclusion in general? And also
>> considering open source postgres as the base for many databases like redshift
>> etc, so the results which apply to progress would apply to others as well.
>>
>> https://www.percona.com/blog/2019/11/22/uuids-are-popular-but-bad-for-performance-lets-discuss/
> I think that[1] provides a good summary.  Performance consideration is just one
> aspect.  Is there a technical requirement for using UUID over sequential values?
>
> If there's a single generator of primary keys use bigint sequences.  In case of
> multiple generators (multi-master replication, sharding, clients generating IDs)
> consider UUID.
>
> There are arguments against sequential PK, e.g. they give away too much info and
> allow attacks such as forced browsing[2].  The first I can understand: you may
> not want to reveal the number of users or customers.  But access control should
> prevent forced browsing.

Shouldn't your application layer isolate the users from the database?  UUIDs 
are all over the DBs I manage, but the PKs are all sequences.

-- 
Born in Arizona, moved to Babylonia.