How to maintain chat data?

I have a curious question... I wanted to know how to maintain chat data in a database. I have been using a php-mysql application, that stores chat data of users in a database.

Now my question is that, if the chat data increases, say, to some millions of records, how to store it? Does mysql support it, or have any limitations or burden ?

Take the example of gmail chat. I can chat unlimited and can also retrieve all my previous chat data. How is it possible ?

Can anyone answer this typical question of myne ?开发者_Go百科

Chat history isn't really that heavyweight. If I calculate around 100 bytes per message, 6 messages per minute, and 5 hours per day, (that is a very talkative chatter, though), permanently, as a worst case, that would give about 61MB per user per year (!). That means with 1 million talkative chatters (very unprobable) you would need around 58TB or data storage.

Saying that this is a worst-case calculation, I would start off with a maximum of 1TB storage, set up the database, and see how things are going. It is highly unprobably for a very young service to evolve that fast.

Also, I would personally not recommend using a Windows system for something like this, unless you know very well what you're doing. MySQL on a Debian distribution will store billions of records, and probably do this faster due to less OS-level limitations (see the MySQL documentation for details, there should be section about the limitations on Windows).

MySQL will happily store millions, even billions of records; but some of the numeric types won't be enough: see this for the maxima of numeric types. As you can see, it would be better to use BIGINT UNSIGNED for e.g. autoincrement fields.

Performance may become a problem for large tables, but that can be mostly solved with indexes (meaning "I've seen performance decrease somewhere around the 100GB mark in a similar situation").

Google has vast amounts of custom storage designed by it for its requirements. What I suggest is you determine your requirements more concretely and determine the platform you need.