What does tweet id means?

[亮亮 王]

For example, I have one tweet created at 2011-02-24 09:08:30 , its id
is 40775075934244864
and another tweet created at 2011-02-24 09:08:31, its id is
40775079306604544

Does this mean that in just 1 second, there have been 3372359680
tweets sent? It seems very impossible.(3.3billion one second?)

40775079306604544
- 40775075934244864
------------------------------------
= 3372359680

If not, can somebody explain what the twitter id means?

[Tim Meadowcroft]

I think you can only really rely on IDs having different values.

In general, at the moment with Twitter, you could assume they increase over time, but (and I don't work for Twitter) typically ID allocation on large multihost systems don't work by allocating strictly sequential IDs without gaps - it's too hard to sequence and not really necessary.

So, for example, one way is that you build a system that gives different ID-assigning-hosts small blocks of IDs that they can use so they can allocate a series of IDs knowing they're unique without having to take out any kind of global lock (they only take the lock to ask for a new block every now and then). Another approach might be to have clocks synchronised to some known accuracy and have IDs calculated as "period-since-epoch * some-suitable-multiplier + unique-offset-per-host + incrementing-counter-for-this-host". 

I'm sure people can come up with other schemes as quick as we could type them up, but in general you make your ID space many orders of magnitude bigger than you strictly need, and in return you gain some flexibility in the criteria needed for quick and cheap unique allocation in a distributed system. But I wouldn't assume that every possible ID value is necessarily allocated.

[Damon Clinkscales]

On Wed, Apr 20, 2011 at 6:24 AM, Tim Meadowcroft <mee...@gmail.com> wrote:

I think you can only really rely on IDs having different values.

In general, at the moment with Twitter, you could assume they increase over time, but (and I don't work for Twitter) typically ID allocation on large multihost systems don't work by allocating strictly sequential IDs without gaps - it's too hard to sequence and not really necessary.

Yes, this is how they do it.

https://github.com/twitter/snowflake

/damon 

[Leo]

So that means we can not infer how many tweets are being sent from
tweet id.

I was wondering who is counting daily number of tweets.

Of course Twitter is doing this itself, but the result goes public
very late.

[Arnaud Meunier]

Hey Leo,

We're indeed using Snowflake (a Tweet ID generation service we developed). Tweets IDs are no longer sequential (but k-sorted with k <= 1 second), and there is no way to count the total number of tweet sent every day.

More info about Snowflake on our Engineering Blog: http://engineering.twitter.com/2010/06/announcing-snowflake.html 

Arnaud / @rno

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