Re: Sequence vs UUID

On 1/30/23 11:43, veem v wrote:
> Thank You So much for the details. I am a bit new to postgres. And these 
> test results I picked were from a dev system. If I understand it 
> correctly, do you mean these settings(usage of C locale or "native" 
> 16-byte uuid) which you mentioned should be there in a production system 
>   and thus we should test the performance of the UUID vs sequence on a 
> similar setup? Or say if this sort of degradation of UUID performance is 
> not expected then , how to get these settings tweaked ON, so as to see 
> the best string type or UUID performance, can you please guide me here?

No what is being said is change:

source_id varchar(36)

to

source_id uuid

as i:

https://www.postgresql.org/docs/current/datatype-uuid.html

> 
> On Mon, 30 Jan 2023 at 22:18, Tom Lane <tgl@sss.pgh.pa.us 
> <mailto:tgl@sss.pgh.pa.us>> wrote:
> 
>     Dominique Devienne <ddevienne@gmail.com
>     <mailto:ddevienne@gmail.com>> writes:
>      > On Mon, Jan 30, 2023 at 5:11 PM veem v <veema0000@gmail.com
>     <mailto:veema0000@gmail.com>> wrote:
>      >> CREATE TABLE test1_UUID ( id bigint,source_id varchar(36)
>     PRIMARY KEY, Name varchar(20) );
> 
>      > Maybe if you used a "native" 16-byte uuid, instead of its textual
>      > serialization with dashes (36 bytes + length overhead), the gap would
>      > narrow.
> 
>     Yeah, especially if your database is not using C locale.  The
>     strcoll or ICU-based comparisons done on string types can be
>     enormously more expensive than the memcmp() used for binary
>     types like native uuid.
> 
>                              regards, tom lane
> 

-- 
Adrian Klaver
adrian.klaver@aklaver.com