可以通过编程方式更新的系统全局计数器（在各种Linux版本上）？

Question

I need some fast method to update key/value type data or alternatively an arbitrary amount of "counters" system-wide on Linux. The systems in question are Ubuntu 10.04, RHEL 4.8 and RHEL 5.x.

Now, I am aware of memcached, but it seems to be more suited for long-running processes, such as FastCGI processes. Unfortunately my process is a traditional CGI and therefore has to use some persistent storage outside of the process itself.

What options do I have and which are easiest and cheapest (wrt runtime) to access from C/C++?

Note: this is not to measure the speed (ie performance counters) but to measure the number a certain type of event happens. And in order to count reliably, I need to be able to atomically increment the counters at will ...

Answer 1

You could try a small SQLite database. SQLite is FAST and reliable, any application can modify it and a transaction method prevents collision. Just add a record to a table for each event, or use a single table with an [event] column. Inserting is really fast, what's slow is searching, but you'll only search when analysing the data, hopefully AFTER the performance is a factor.

Answer 2

您可以使用简单的类似DBM的数据库，例如GDBM 。

Answer 3

Nowadays, in order

to update key/value type data

Developers often use NoSQL databases. They run mainly on linux systems, and some of them are in C++ ( MongoDB & ClusterPoint ). They are really fast for this kind of things, they try really hard to keep low latency and it should be easy to access it from C++ since they are coded in C++.