recreate sequence g; commit;
recreate table t( f01 int ); commit;
set term ^;
execute block as
declare n int = 10000000; 
begin
while(n>0) do insert into t(f01) values( mod( gen_id(g,1), 2) ) returning :n-1 into n;
end^ 
set term ;^ 
commit;

G:\1INSTALL\FIREBIRD\FB30>dir zero.fdb|findstr /i /c:zero.fdb
21.12.2013  02:03          514 306 048  ZERO.FDB

Database "G:\1INSTALL\FIREBIRD\FB30\ZERO.FDB"
Database header page information:
 
 
 head info	Flags			0
	Generation		40
	System Change Number	0
	Page size		4096
	ODS version		12.0
	Oldest transaction	33
	Oldest active		34
	Oldest snapshot		34
	Next transaction	35
	Sequence number		0
	Next attachment ID	12
	Implementation		HW=Intel/i386 little-endian OS=Windows CC=MSVC
	Shadow count		0
	Page buffers		0
	Next header page	0
	Database dialect	3
	Creation date		Dec 21, 2013 1:52:55
	Attributes		

    Variable header data:
	*END*


Database file sequence:
File G:\1INSTALL\FIREBIRD\FB30\ZERO.FDB is the only file
 
Analyzing database pages ...
T (129)
    Primary pointer page: 12575, Index root page: 12576
    Total formats: 1, used formats: 1
     Average record length: 9.00, total records: 10000000 
    Average version length: 0.00, total versions: 0, max versions: 0
    Average fragment length: 0.00, total fragments: 0, max fragments: 0
    Average unpacked length: 8.00, compression ratio: 0.89
    Pointer pages: 137, data page slots: 123457
    Data pages: 123457,  average fill: 52% 
    Primary pages: 123457, full pages: 123456, swept pages: 0
    Fill distribution:
	 0 - 19% = 0
	20 - 39% = 0
	40 - 59% = 123457
	60 - 79% = 0
	80 - 99% = 0