What's more efficient - storing logs in sql database or files?

Question

I have few scripts loaded by cron quite often. Right now I don't store any logs, so if any script fails to load, I won't know it till I see results - and even when I notice that results are not correct, I can't do anything since I don't know which script failed.

I've decided to store logs, but I am still not sure how to do it. So, my question is - what's more efficient - storing logs in sql database or files?

I can create 'logs' table in my mysql database and store each log in separate row, or I can just use php's file_put_contents or fopen/fwrite to store logs in separate files.

My scripts would approximately add 5 logs (in total) per minute while working. I've done few tests to determine what's faster - fopen/fwrite or mysql's insert. I looped an "insert" statement 3000 times to make 3000 rows and looped fopen/fwrite 3000 times to make 3000 files with sample text. Fwrite executed 4-5 times faster than sql's insert. I made a second loop - I looped a 'select' statement and assigned it to a string 3000 times - I also opened 3000 files using 'fopen' and assigned the results to the string. Result was the same - fopen/fwrite finished the task 4-5 times faster.

So, to all experienced programmers - what's your experience with storing logs? Any advice?

// 04.09.2011 EDIT - Thank you all for your answers, they helped ma a lot. Each post were valuable, so it was quite hard to accept only one answer ;-)

Answer 1

Logs using files are more efficient, however logs stored in the database are easier to read, even remotely (you can write a web frontend if required, for example).

Note however that connecting and inserting rows into the database is error prone (database server down, password wrong, out-of-resources) so where would you log those errors if you decided to use the database?