Using slightly modified test case of CORE-3011 :

inp.sql

with
nx as
(
  select 0 i from rdb$database union all select 1 from rdb$database union all
  select 2 from rdb$database union all select 3 from rdb$database union all
  select 4 from rdb$database union all select 5 from rdb$database
)
select count(*) from nx n5, nx n4, nx n3, nx n2, nx n1, nx n0 where n5.i+n4.i+n3.i = n2.i+n1.i+n0.i;

select count(*) from mon$attachments;

with
nx as
(
  select 0 i from rdb$database union all select 1 from rdb$database union all
  select 2 from rdb$database union all select 3 from rdb$database union all
  select 4 from rdb$database union all select 5 from rdb$database
)
select count(*) from nx n5, nx n4, nx n3, nx n2, nx n1, nx n0 where n5.i+n4.i+n3.i = n2.i+n1.i+n0.i;

exit;



test.bat

@echo off
SET FB=F:\FB2\fb25.clean\temp\Win32\Release\firebird\bin
SET DB=localhost:%FB%\a.fdb

rem -o out_%%i_%%j.txt
rem -o out_%%i.txt

for /L %%i in (1,1,%1) do (
   echo %%i
   for /L %%j in (1,1,%2) do start /MIN %FB%\isql %DB% -u SYSDBA -p masterke -i inp.sql -o out_%%i_%%j.txt -m -m2
   %FB%\isql %DB% -u SYSDBA -p masterke -i inp.sql -o out_%%i_0.txt -m -m2
)


Run

test 250 25

and look into firebird.log after test ends. It will contain messages such as

Cannot initialize the shared memory region
operating system directive CreateFile failed
Access is denied.

Cannot initialize the shared memory region
operating system directive WaitForSingleObject failed
Cannot create a file when that file already exists.

Cannot initialize the shared memory region
operating system directive CreateFile failed
The process cannot access the file because it is being used by another process.