How to use sequential guid?

[niltor]

Question

I want to know how to configure a sequence Guid in Npgsql.

Description

Nuget package:Npgsql.EntityFrameworkCore.PostgreSQL, Version="6.0.4"

In Entityframework Core 6, as Microsoft docs mention:
Explicitly configuring value generation,
In this article's warning section, there are :

For example, on SQL Server, when a GUID property is configured as a value generated on add, the provider automatically performs value generation client-side, using an algorithm to generate optimal sequential GUID values.

So, How to configure a sequence Guid in Npgsql.

[roji]

@niltor the Npgsql provider works the same way - Guid keys are generated client-side by default. Note that this isn't a "sequence" - sequences in this context are usually a database generation technique (so not client side), but sequences only support numbers.

[roji]

The Npgsql docs for this are here.

[niltor]

@niltor the Npgsql provider works the same way - Guid keys are generated client-side by default. Note that this isn't a "sequence" - sequences in this context are usually a database generation technique (so not client side), but sequences only support numbers.

@roji
Thanks for the reply!

Yes, I know what you said. If I use MySQL or SQLServer, I can find a provider to help me deal with sequence GUID. Just like:

Pomelo.EntityFrameworkCore.MySql

I had already searched and read some docs, it seems that Npgsql did not provide this feature, or can we implement it with other methods?

If we can't implement it easily now, Is there a plan to support this feature?

[roji]

@niltor I don't understand - as I wrote above, Npgsql generates client-side GUID values for key properties, similar to what the SQL Server provides. What exactly are you missing here?

[niltor]

It's simple question as the issue title.

For example, on SQL Server, when a GUID property is configured as a value generated on add, the provider automatically performs value generation client-side, using an algorithm to generate optimal sequential GUID values.

So how to use sequential GUID in Npgsql as SQLServer.

[roji]

@niltor what is your reason for wanting to generate a sequential GUID for PostgreSQL? In SQL Server this is necessary to make indexes operate efficiently, but I'm not aware of such a characteristic in PostgreSQL (would be happy to learn something new if otherwise).

[roji]

Closing as no response was provided, but can reopen if necessary.

[maddandy]

Hi @roji ,

"In SQL Server this is necessary to make indexes operate efficiently", why not for PostgreSQL ?
I guess, it can be more efficient on sort or filter operation like in SQL Server.

I would like to be able to generate this kind of Guid in progreSQL too, I tried the SequentialGuidValueGenerator provided by Microsoft, it's works, but when I tried to sort my column, the data is managed like a string

[roji]

I guess, it can be more efficient on sort or filter operation like in SQL Server.

Is this assumption based on anything? If so, can you point to where this is shown? Different databases work differently; I wouldn't simply assume that sequential GUIDs bring any specific benefit in PostgreSQL.