How to reduce request to my db?

i have a db that store many posts, like a blog. The problem is that exist many users and this users create many post at the same t开发者_JS百科ime. So, when a user request the home page i request this posts to db. In less words, i've to get the posts that i've showed, for show the new ones. How can i avoid this performance problem?

Before going down a caching path ensure

1. Review the logic (are you undertaking unnecessary steps, can you populate some memory variables with slow changing data and so reduce DB calls, etc)
2. Ensure DB operations are as distinct as possible (minimum rows and columns returned)
3. Data is normalised to at least 3rd normal form and then selectively denormalised with the appropriate data handling routines for the denormalised data.
4. After normalisation, tune the DB instance (server perfomance, disk IO, memory, etc)
5. Tune the SQL statements

Then ...

1. Consider caching. Even though it is not possible to cache all data, if you can get a significant percentage into cache for a reasonable period of time (and those values vary according to site) you remove load from the DB server and so other queries can be served faster.

do you do any type of pagination? if not database pagination would be the best bet... start with the first 10 posts, and after that only return the full list of the user requests it from a link or some other input.

The standard solution is to use something like memcached to offload common reads to a caching layer. So you might decide to only refresh the home page once every 5 minutes rather than hitting the database repeatedly with the same exact query.

If there are data which is requested very often, you should cache it. Try using an in-memory cache such as memcached to store things that are likely to be re-requested in short time. You should have free RAM for this: try using free memory on your frontend machine(s), usually serving HTTP requests and applying templates is less RAM-intensive. BTW, you can cache not only raw DB records, but also ready-made pieces of pages with formatting and all.

If your load cannot be reasonably handled by one machine, try sharding your database. Put data of some of your users (posts, comments, etc) on one machine, data of other users to another machine, etc. This will make some joins impossible on database level, because data are on different machines, but joins that you do often will be parallelized.

Also, take a look at document-oriented 'NoSQL' data stores like (MongoDB)[http://www.mongodb.org/]. It e.g. allows you to store a post and all comments to it in a single record and fetch in one operation, without any joins. But regular joins are next to impossible. Probably a mix of SQL and NoSQL storage is most efficient (and hard to handle).