perlのDBIのDEBUG

cliから実行するときにDBI_TRACE環境変数を設定。

• perldoc DBI

output appended to that file. If the name begins with a number followed
by an equal sign ("="), then the number and the equal sign are stripped
off from the name, and the number is used to set the trace level. For
example:

  DBI_TRACE=1=dbitrace.log perl your_test_script.pl

On Unix‐like systems using a Bourne‐like shell, you can do this easily
on the command line:

  DBI_TRACE=2 perl your_test_script.pl