Description of problem:
Occured during # dnf upgrade --refresh command

Version-Release number of selected component:
dnf-4.0.4-1.fc30

Additional info:
reporter:       libreport-2.9.6
cmdline:        /usr/bin/python3 /usr/bin/dnf upgrade --refresh
crash_function: __init__
exception_type: RuntimeError
executable:     /usr/bin/dnf
interpreter:    python3-3.7.0-10.fc30.x86_64
kernel:         4.19.0-0.rc7.git4.1.fc30.x86_64
runlevel:       N 5
type:           Python3
uid:            0

Truncated backtrace:
transaction.py:729:__init__:RuntimeError: Exec failed: database is locked

Traceback (most recent call last):
  File "/usr/bin/dnf", line 58, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 179, in user_main
    errcode = main(args)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 64, in main
    return _main(base, args, cli_class, option_parser_class)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 99, in _main
    return cli_run(cli, base)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 123, in cli_run
    ret = resolving(cli, base)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 154, in resolving
    base.do_transaction(display=displays)
  File "/usr/lib/python3.7/site-packages/dnf/cli/cli.py", line 235, in do_transaction
    tid = super(BaseCli, self).do_transaction(display)
  File "/usr/lib/python3.7/site-packages/dnf/base.py", line 847, in do_transaction
    # put back our depcheck callback
  File "/usr/lib/python3.7/site-packages/dnf/base.py", line 997, in _run_transaction
    try:
  File "/usr/lib/python3.7/site-packages/dnf/base.py", line 1035, in _verify_transaction
  File "/usr/lib/python3.7/site-packages/dnf/db/history.py", line 508, in end
    self.swdb.initTransaction()
  File "/usr/lib/python3.7/site-packages/dnf/db/history.py", line 291, in swdb
    self._swdb = libdnf.transaction.Swdb(self.dbpath)
  File "/usr/lib64/python3.7/site-packages/libdnf/transaction.py", line 729, in __init__
    this = _transaction.new_Swdb(*args)
RuntimeError: Exec failed: database is locked

Local variables in innermost frame:
self: <libdnf.transaction.Swdb;  >
args: ('/var/lib/dnf/history.sqlite',)

Potential duplicate: bug 1636886