What do you use to create system logging?

Question

Journaling

The question concerns web projects (in principle, it doesn’t matter what they are written on).
What do you use to generate logs?
write them to the database? And to inflate the volume of the table is unprofitable. Those. for example, such a table can contain more than 6 million lines on a large project and very soon :)
it may be easier to add to the file by record easier (faster), but such logs are more difficult to process.
What logs are we talking about?
for example, such
and such a user at such and such a time performed such and such an action, received or sent such and such data, etc. ...
maybe there are some solutions that can already be used?
any ideas?

Answer 1

If for some reason one table does not suit you (although, study such things as clustering), then you can automatically create a paired table for each table according to the database structure, filled with triggers, while the filling logic for different tables can be varied - for some, only the facts of adding are stored and deletion, for others, add modification facts, for others, you may need data reading facts (this data can be filled in without triggers), somewhere you can even have a complete log of data changes (save the changed fields for the history of changes) ...
The problem is then to interpret this data ... but , the possibilities that this approach provides are very large.