write log at web services scenario

[Mullin Yu]

hi,

i'm using c# to write a web services, and want to write the application log
to a file, and i have the following concerns:

1. may be more than one request at the same, any locking issue if write to
file?

2. may be more than one request at the same, the log content may be mixed
together and then can't really trace the log

what's the usual practice to handle this? do i need to give another unqiue
id for every coming request and write then write the log like the following.
at least, from the unique id, i can distinguish among the requests.

[0000001] Start applicatin
[0000001] Read db
[0000002] Start applicatin
[0000002] Read db
[0000001] Insert data
[0000001] Commit
[0000001] Query
[0000002] Insert data
[0000002] Commit
[0000002] Query