phatboyg/newid

A sequential id generator that works across nodes with no collisions

newid's Issues

Which type of sequential guid

Hey, I am just curious about which type of sequential guid you are using?

Because if you want increase performance in MSSQL you need to use sequential at end, and for MySql you need to use sequential at beginning.

Unique Id across all microservices

Hi,
Thanks for this useful package.
Could we create a unique ID across all services? Should we config each service instance separately to ensuring about uniqueness ?

Get running on `dotnet` cli / .NET Core

Get NewId running on .net core.

Bug when parsing a SequentialGuid.

FromSequentialGuid incorrectly swaps the bytes of the sequence counter, this means that parsing SequentialGuid creates incorrect NewIds. Tests won't detect this because the first NewId generated has the sequence number 0x0000.
This bug was introduced in #20 affecting FromSequentialGuid and ToNewIdFromSequential.

Expected: 9bfb0100-e3f8-6a00-06a1-08daed27ef21
But was:  9bfb0001-e3f8-6a00-06a1-08daed27ef21

Example failing test

// Round trip, to SequentialGuid and back with FromSequentialGuid
[Test]
public void Should_parse_sequential_guid_2_as_newid()
{
    NewId n = NewId.Next(2)[1];

    var nn = n.ToGuid();
    var g = n.ToSequentialGuid();

    var ng = NewId.FromSequentialGuid(g);

    Assert.AreEqual(n, ng);

    // Also checks to see if this would throw
    Assert.IsTrue(ng.Timestamp != default);
}

Fix

static void FromSequentialByteArray(in byte[] bytes, out Int32 a, out Int32 b, out Int32 c, out Int32 d)
{
    a = bytes[3] << 24 | bytes[2] << 16 | bytes[1] << 8 | bytes[0];
    b = bytes[5] << 24 | bytes[4] << 16 | bytes[7] << 8 | bytes[6];
    c = bytes[8] << 24 | bytes[9] << 16 | bytes[10] << 8 | bytes[11];
    d = bytes[12] << 24 | bytes[13] << 16 | bytes[14] << 8 | bytes[15];
}

Why MassTransit namespace

Is this project somehow related to/intended to work along with MassTransit?

Add greater and less than operators to NewId

Hi,
I really like your library as it solves the problem of sequential id generation for me. However, I'd really like to have greater/less than operators available to NewId so I don't need to use CompareTo methods.
I've just created a PR ( #11 ) that adds it. Could you please consider mergin it to your library?

Thanks!

Sort guid

There is a column of time, but the time is not the latest on the top, why is it that order by id ,guid is not generated according to time?

Collisions of Ids

Hi guys,

I know the Flake ago produces nice looking sequential GUIDs. However, this implementation of the library has the following fatal flaws.

When generating 5M GUIDs using parallel tasks here are the issues:

• It roughly takes 5 seconds to generate 5M GUIDs. This rather slow considering other libraries can produce 5M GUIDs in less than 300ms

• The issue is collisions. After running 5M GUIDs, we detected on average, the same GUID repeated between 70-300 times per run. This is a big concern. I suggest not to use the Flake algo of GUIDs but rather just replace the last 8 bytes of the GUID to use an Unix Epoch Timestamp in milliseconds. Granted the timestamp portion of the GUID can have collisions but due to the fact the remaining part of a natural GUID (minus the last 8 bytes) provides a much better quasi-uniqueness than the Flake algo.

Hope this helps,

codematrix

Add TryParse and TryWriteBytes

Methods should be similar or identical to the ones in the base dotnet Guid type

Performance issue with NewId for Primary key

As in Doc mentioned, we have sequential Id with NewID. In the end, do we get generated sequential Id with ideal performance like int for cluster index?

Question: are you aware of any ports or analogous implementations in java or php?

Hi, thank you for sharing your efforts with the community.

We're operating in a multi-language ecosystem with .NET, Java, and PHP and I was wondering if you happen to know of any ports of this to Java or PHP?

Thank you!

Ambiguous reference in projects that have transitive dependencies on both MassTransit.Abstractions and NewId

In projects that have dependencies on both MassTransit.Abstractions and NewId, the compiler has no way to tell the difference between usages because the class names and namespaces are identical.
@phatboyg have you considered making a breaking change and choosing a new namespace for this standalone library/package?

Edit: I'm aware that having both dependencies is a no-no if you can avoid it, but given that they could be transitive dependencies via NuGet, there are scenarios for which it cannot easily be avoided.