Tamino request log is normally only a feature used for problem analysis.
You need to switch it on explicitly and it writes the log into files on your file system.
It is a rolling file appender, i.e. you can specify how many files and up to which size each file shall be generated. The default values are pretty low. Once all files are generated and filled, it starts to override the oldest file.
To switch it on, you need to call the inoadmin command from the bin folder in the Tamino installation:
inoadmin set “request log” “full” norestart
inoadmin set “XML request log folder” “” norestart
inoadmin set “XML request log file count” “” norestart
inoadmin set “XML request log file max size” “” norestart
Then you have to restart the database. After restart you can find the request log in the specified folder.