Question

I am building my own sharding solution with ASP.NET C# and MySQL. For the Id of each row I use the following:

• Shard Id – Int (1-65535)
• Table Type Id – Small Int (1-65535)
• Incremental number (1 – 4294967295)

So for example, an ID should be in the url like this:

http://mywebsite.com/folders/65535655354294967297

What I want to know is how to combine the numbers into a big number so I can extract the data later on. So for example, I won’t use 1 as the shard ID, I would probably need to you 00001 because later it will be easier to extract that number by making a division on the whole number.

So how can I do that, what is the best way to build a long number with three seperate numerical values and then be able to extract them back in code?

I look for the most efficient way to do it in C#

Thanks.

Answer 1

You can use hex represantations of numbers

ushort ShardId=1;
ushort TableTypeId = 100;
uint IncrementalNumber = 1000;

string url = ShardId.ToString("X4") + TableTypeId.ToString("X4")
                                    + IncrementalNumber.ToString("X8");

var i1 = Convert.ToUInt16(url.Substring(0, 4), 16);
var i2 = Convert.ToUInt16(url.Substring(4, 4), 16);
var i3 = Convert.ToUInt32(url.Substring(8, 8), 16);

OR

string url = (((ulong)ShardId << 48) | ((ulong)TableTypeId << 32) | IncrementalNumber)
             .ToString("X16");

var u  = Convert.ToUInt64(url,16);
var i1 = (ushort)(u >> 48);
var i2 = (ushort)((u >> 32) & 0xffff);
var i3 = (uint)(u & 0xffffffff);