问题
I'm building a chat app and I want a full history off all messages ever sent in the chat conversation. At the moment I am storing each message as a single row in a table called 'messages'. I am aware that this table could grow huge as even small messages like 'Hi' would have their own database record.
Can anyone recommend a more scalable mysql solution? I don't require the individual messages to be searchable, editable or deletable. Could the whole conversation be stored in one huge field?
Would love to hear your ideas!
回答1:
There's nothing wrong with saving the whole history in the database, they are prepared for that kind of tasks.
Actually you can find here in Stack Overflow a link to an example schema for a chat: example
If you are still worried for the size, you could apply some optimizations to group messages, like adding a buffer to your application that you only push after some time (like 1 minute or so); that way you would avoid having only 1 line messages
回答2:
If you can avoid the need for concurrent writes to a single file, it sounds like you do not need a database to store the chat messages.
Just append the conversation to a text file (1 file per user\conversation). and have a directory/ file structure
Here's a simplified view of the file structure:
chat-1-bob.txt
201101011029, hi
201101011030, fine thanks.
chat-1-jen.txt
201101011030, how are you?
201101011035, have you spoken to bill recently?
chat-2-bob.txt
201101021200, hi
201101021222, about 12:22
chat-2-bill.txt
201101021201, Hey Bob,
201101021203, what time do you call this?
You would then only need to store the userid, conversation id (guid ?) & a reference to the file name.
I think you will find it hard to get a more simple scaleable solution.
You can use LOAD_FILE to get the data too see: http://dev.mysql.com/doc/refman/5.0/en/string-functions.html
If you have a requirement to rebuild a conversation you will need to put a value (date time) alongside your sent chat message (in the file) to allow you to merge & sort the files, but at this point it is probably a good idea to consider using a database.
回答3:
You could create a database for x conversations which contains all messages of these conversations. This would allow you to add a new Database (or server) each time x exceeds. X is the number conversations your infrastructure supports (depending on your hardware,...).
The problem is still, that there may be big conversations (with a lot of messages) on the same database. e.g. you have database A and database B an each stores e.g. 1000 conversations. It my be possible that there are far more "big" conversations on server A than on server B (since this is user created content). You could add a "master" database that contains a lookup, on which database/server the single conversations can be found (or you have a schema to assign a database from hash/modulo or something).
Maybe you can find real world architectures that deal with the same problems (you may not be the first one), and that have already been solved.
来源：https://stackoverflow.com/questions/7063051/best-way-to-store-chat-messages-in-a-database