Is there an indexing tool in linux that can help quickly search the contents of all my files?

[Peng Yu <pengyu.ut@gmail.com>]

Hi,

On windows machines, there is "google desktop" which searchs the files
contents. Mac has "spotlight" which also search the file contents in a
mac machine.

In linux, I know the command 'locate' which search all the filenames.
But I am wondering if there is a tool that can search file contents.

I know that the combination of 'find' and 'grep' can search the
contents, but it is slow. Can somebody let me know if there is a much
faster solution which might rely on an indexing database?

Regards,
Peng