Behavior of the block when executed drop,truncate. ASSM

create tablespace MCZIM datafile '+DGLOCAL' size 10M autoextend on next 64M maxsize UNLIMITED EXTENT MANAGEMENT LOCAL UNIFORM SIZE 1M segment space management auto;
create table mczim_test_block tablespace MCZIM as select * from dba_objects where 1=2;
alter system checkpoint;

Status of the first block of table. Block is the empty. We can see HWM in the block.

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00100 (643/256)
scn: 0x008c.1149c039 seq: 0x01 flg: 0x04 tail: 0xc0392001
frmt: 0x02 chkval: 0x05f9 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00100 1149C039 0401008C [ .......9.I.....]
2ADEB19C1010 000005F9 00000000 00000000 00000000 [................]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 0000003A 00000006 00000040 [....:.......@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000006 00000000 00000000 [................]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000000 00000000 00000006 [................]
2ADEB19C10A0 00000100 A0C00106 00000000 00000000 [................]
2ADEB19C10B0 00000000 00000000 00000000 00000001 [................]
2ADEB19C10C0 0004CE66 58303438 0000004D A0C00100 [f...840XM.......]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 00111111 [................]
2ADEB19C1190 00000000 00000000 00000000 00000000 [................]
 Repeat 229 times
2ADEB19C1FF0 00000000 00000000 00000000 C0392001 [............. 9.]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 0
 unformatted: 58 total: 64 first useful block: 6
 owning instance : 1
 instance ownership changed at
 Last successful Search
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 6
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 1479554104.77
 Flag: 0x00000001 (-/-/-/-/-/HWM)
 Inc #: 0 Objd: 314982
 HWM Flag: HWM Set
 Highwater:: 0xa0c00106 ext#: 0 blk#: 6 ext size: 256
 #blocks in seg. hdr's freelists: 0
 #blocks below: 0
 mapblk 0x00000000 offset: 0
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00100 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:Metadata 5:Metadata 6:unformatted 7:unformatted
 8:unformatted 9:unformatted 10:unformatted 11:unformatted
 12:unformatted 13:unformatted 14:unformatted 15:unformatted
 16:unformatted 17:unformatted 18:unformatted 19:unformatted
 20:unformatted 21:unformatted 22:unformatted 23:unformatted
 24:unformatted 25:unformatted 26:unformatted 27:unformatted
 28:unformatted 29:unformatted 30:unformatted 31:unformatted
 32:unformatted 33:unformatted 34:unformatted 35:unformatted
 36:unformatted 37:unformatted 38:unformatted 39:unformatted
 40:unformatted 41:unformatted 42:unformatted 43:unformatted
 44:unformatted 45:unformatted 46:unformatted 47:unformatted
 48:unformatted 49:unformatted 50:unformatted 51:unformatted
 52:unformatted 53:unformatted 54:unformatted 55:unformatted
 56:unformatted 57:unformatted 58:unformatted 59:unformatted
 60:unformatted 61:unformatted 62:unformatted 63:unformatted
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 256 maxblk 256

Insert data.

insert into system.mczim_test_block(select * from dba_objects);
commit;
alter system checkpoint;

Status of the first block of table. HWM is gone.

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00100 (643/256)
scn: 0x008c.11495346 seq: 0x33 flg: 0x04 tail: 0x53462033
frmt: 0x02 chkval: 0xb442 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB1633A00 to 0x00002ADEB1634A00
2ADEB1633A00 00008220 A0C00100 11495346 0433008C [ .......FSI...3.]
2ADEB1633A10 0000B442 00000000 00000000 00000000 [B...............]
2ADEB1633A20 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB1633A40 00000000 00000000 00000000 00000004 [................]
2ADEB1633A50 FFFFFFFF 00000000 00000006 00000040 [............@...]
2ADEB1633A60 00010001 00000000 00000000 00000000 [................]
2ADEB1633A70 00000000 00000040 51599CC0 51599CC0 [....@.....YQ..YQ]
2ADEB1633A80 00000000 00000000 00000000 00000000 [................]
2ADEB1633A90 A0C00104 00000000 00000000 00000000 [................]
2ADEB1633AA0 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB1633AC0 0004CE60 58303438 0000004D A0C00100 [`...840XM.......]
2ADEB1633AD0 00000040 00000000 00000000 00000000 [@...............]
2ADEB1633AE0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB1633B80 00000000 00000000 00000000 11111111 [................]
2ADEB1633B90 11111111 11111111 11111111 11111111 [................]
2ADEB1633BA0 11111111 11111111 11111111 00000000 [................]
2ADEB1633BB0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB16349F0 00000000 00000000 00000000 53462033 [............3 FS]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 0
 unformatted: 0 total: 64 first useful block: 6
 owning instance : 1
 instance ownership changed at 04/01/2013 18:42:08
 Last successful Search 04/01/2013 18:42:08
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 64
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 1479554104.77
 Flag: 0x00000000 (-/-/-/-/-/-)
 Inc #: 0 Objd: 314976
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00100 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:Metadata 5:Metadata 6:FULL 7:FULL
 8:FULL 9:FULL 10:FULL 11:FULL
 12:FULL 13:FULL 14:FULL 15:FULL
 16:FULL 17:FULL 18:FULL 19:FULL
 20:FULL 21:FULL 22:FULL 23:FULL
 24:FULL 25:FULL 26:FULL 27:FULL
 28:FULL 29:FULL 30:FULL 31:FULL
 32:FULL 33:FULL 34:FULL 35:FULL
 36:FULL 37:FULL 38:FULL 39:FULL
 40:FULL 41:FULL 42:FULL 43:FULL
 44:FULL 45:FULL 46:FULL 47:FULL
 48:FULL 49:FULL 50:FULL 51:FULL
 52:FULL 53:FULL 54:FULL 55:FULL
 56:FULL 57:FULL 58:FULL 59:FULL
 60:FULL 61:FULL 62:FULL 63:FULL
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 256 maxblk 256

Drop table.

drop table system.mczim_test_block;
alter system checkpoint;

Status of the first block will not change.

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00100 (643/256)
scn: 0x008c.11495346 seq: 0x33 flg: 0x04 tail: 0x53462033
frmt: 0x02 chkval: 0xb442 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00100 11495346 0433008C [ .......FSI...3.]
2ADEB19C1010 0000B442 00000000 00000000 00000000 [B...............]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 00000000 00000006 00000040 [............@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000040 51599CC0 51599CC0 [....@.....YQ..YQ]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000000 00000000 00000000 [................]
2ADEB19C10A0 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C10C0 0004CE60 58303438 0000004D A0C00100 [`...840XM.......]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 11111111 [................]
2ADEB19C1190 11111111 11111111 11111111 11111111 [................]
2ADEB19C11A0 11111111 11111111 11111111 00000000 [................]
2ADEB19C11B0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB19C1FF0 00000000 00000000 00000000 53462033 [............3 FS]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 0
 unformatted: 0 total: 64 first useful block: 6
 owning instance : 1
 instance ownership changed at 04/01/2013 18:42:08
 Last successful Search 04/01/2013 18:42:08
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 64
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 1479554104.77
 Flag: 0x00000000 (-/-/-/-/-/-)
 Inc #: 0 Objd: 314976
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00100 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:Metadata 5:Metadata 6:FULL 7:FULL
 8:FULL 9:FULL 10:FULL 11:FULL
 12:FULL 13:FULL 14:FULL 15:FULL
 16:FULL 17:FULL 18:FULL 19:FULL
 20:FULL 21:FULL 22:FULL 23:FULL
 24:FULL 25:FULL 26:FULL 27:FULL
 28:FULL 29:FULL 30:FULL 31:FULL
 32:FULL 33:FULL 34:FULL 35:FULL
 36:FULL 37:FULL 38:FULL 39:FULL
 40:FULL 41:FULL 42:FULL 43:FULL
 44:FULL 45:FULL 46:FULL 47:FULL
 48:FULL 49:FULL 50:FULL 51:FULL
 52:FULL 53:FULL 54:FULL 55:FULL
 56:FULL 57:FULL 58:FULL 59:FULL
 60:FULL 61:FULL 62:FULL 63:FULL
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 256 maxblk 256

Recreate table, but now we have to insert data immediatly. And now we not see HWM in the block.

drop tablespace MCZIM including contents and datafiles
create tablespace MCZIM datafile '+DGLOCAL' size 10M autoextend on next 64M maxsize UNLIMITED EXTENT MANAGEMENT LOCAL UNIFORM SIZE 1M segment space management auto
create table mczim_test_block tablespace MCZIM as select * from dba_objects where 1=2
insert into system.mczim_test_block(select * from dba_objects);
commit;
alter system checkpoint;

 

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00100 (643/256)
scn: 0x008c.114958fd seq: 0x09 flg: 0x04 tail: 0x58fd2009
frmt: 0x02 chkval: 0xb443 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00100 114958FD 0409008C [ ........XI.....]
2ADEB19C1010 0000B443 00000000 00000000 00000000 [C...............]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 00000000 00000006 00000040 [............@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000040 51599D96 51599D96 [....@.....YQ..YQ]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000000 00000000 00000000 [................]
2ADEB19C10A0 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C10C0 0004CE61 58303438 0000004D A0C00100 [a...840XM.......]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 11111111 [................]
2ADEB19C1190 11111111 11111111 11111111 11111111 [................]
2ADEB19C11A0 11111111 11111111 11111111 00000000 [................]
2ADEB19C11B0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB19C1FF0 00000000 00000000 00000000 58FD2009 [............. .X]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 0
 unformatted: 0 total: 64 first useful block: 6
 owning instance : 1
 instance ownership changed at 04/01/2013 18:45:42
 Last successful Search 04/01/2013 18:45:42
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 64
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 1479554104.77
 Flag: 0x00000000 (-/-/-/-/-/-)
 Inc #: 0 Objd: 314977
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00100 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:Metadata 5:Metadata 6:FULL 7:FULL
 8:FULL 9:FULL 10:FULL 11:FULL
 12:FULL 13:FULL 14:FULL 15:FULL
 16:FULL 17:FULL 18:FULL 19:FULL
 20:FULL 21:FULL 22:FULL 23:FULL
 24:FULL 25:FULL 26:FULL 27:FULL
 28:FULL 29:FULL 30:FULL 31:FULL
 32:FULL 33:FULL 34:FULL 35:FULL
 36:FULL 37:FULL 38:FULL 39:FULL
 40:FULL 41:FULL 42:FULL 43:FULL
 44:FULL 45:FULL 46:FULL 47:FULL
 48:FULL 49:FULL 50:FULL 51:FULL
 52:FULL 53:FULL 54:FULL 55:FULL
 56:FULL 57:FULL 58:FULL 59:FULL
 60:FULL 61:FULL 62:FULL 63:FULL
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 256 maxblk 256

Truncate table.

truncate table system.mczim_test_block;
alter system checkpoint;

HWM will be inserted to the first block and block will be formatted.

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00100 (643/256)
scn: 0x008c.11496106 seq: 0x02 flg: 0x04 tail: 0x61062002
frmt: 0x02 chkval: 0x6f68 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00100 11496106 0402008C [ ........aI.....]
2ADEB19C1010 00006F68 00000000 00000000 00000000 [ho..............]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 0000003A 00000006 00000040 [....:.......@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000006 51599D96 51599D96 [..........YQ..YQ]
2ADEB19C1080 00000000 000A000A 0016762C 00000009 [........,v......]
2ADEB19C1090 A0C00104 00000000 00000000 00000006 [................]
2ADEB19C10A0 00000100 A0C00106 00000000 00000000 [................]
2ADEB19C10B0 00000000 00000000 00000000 00000021 [............!...]
2ADEB19C10C0 0004CE62 11496106 0000008C A0C00100 [b....aI.........]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 00111111 [................]
2ADEB19C1190 00000000 00000000 00000000 00000000 [................]
 Repeat 229 times
2ADEB19C1FF0 00000000 00000000 00000000 61062002 [............. .a]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 0
 unformatted: 58 total: 64 first useful block: 6
 owning instance : 1
 instance ownership changed at 04/01/2013 18:45:42
 Last successful Search 04/01/2013 18:45:42
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 6
 Bitmap block lock opcode 9
 Locker xid: : 0x000a.00a.0016762c
 Dealloc scn: 290021638.140
 Flag: 0x00000021 (OBJD/-/-/-/-/HWM)
 Inc #: 0 Objd: 314978
 HWM Flag: HWM Set
 Highwater:: 0xa0c00106 ext#: 0 blk#: 6 ext size: 256
 #blocks in seg. hdr's freelists: 0
 #blocks below: 0
 mapblk 0x00000000 offset: 0
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00100 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:Metadata 5:Metadata 6:unformatted 7:unformatted
 8:unformatted 9:unformatted 10:unformatted 11:unformatted
 12:unformatted 13:unformatted 14:unformatted 15:unformatted
 16:unformatted 17:unformatted 18:unformatted 19:unformatted
 20:unformatted 21:unformatted 22:unformatted 23:unformatted
 24:unformatted 25:unformatted 26:unformatted 27:unformatted
 28:unformatted 29:unformatted 30:unformatted 31:unformatted
 32:unformatted 33:unformatted 34:unformatted 35:unformatted
 36:unformatted 37:unformatted 38:unformatted 39:unformatted
 40:unformatted 41:unformatted 42:unformatted 43:unformatted
 44:unformatted 45:unformatted 46:unformatted 47:unformatted
 48:unformatted 49:unformatted 50:unformatted 51:unformatted
 52:unformatted 53:unformatted 54:unformatted 55:unformatted
 56:unformatted 57:unformatted 58:unformatted 59:unformatted
 60:unformatted 61:unformatted 62:unformatted 63:unformatted
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 256 maxblk 256

Reinsert data.

insert into system.mczim_test_block(select * from dba_objects);
alter system checkpoint;

HWM is gone.

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00100 (643/256)
scn: 0x008c.114961bd seq: 0x0c flg: 0x04 tail: 0x61bd200c
frmt: 0x02 chkval: 0xa8e6 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00100 114961BD 040C008C [ ........aI.....]
2ADEB19C1010 0000A8E6 00000000 00000000 00000000 [................]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 00000000 00000006 00000040 [............@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000040 51599FCA 51599FCA [....@.....YQ..YQ]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000000 00000000 00000000 [................]
2ADEB19C10A0 00000000 00000000 00000000 00000000 [................]
2ADEB19C10B0 00000000 00000000 00000000 00000020 [............ ...]
2ADEB19C10C0 0004CE62 11496106 0000008C A0C00100 [b....aI.........]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 11111111 [................]
2ADEB19C1190 11111111 11111111 11111111 11111111 [................]
2ADEB19C11A0 11111111 11111111 11111111 00000000 [................]
2ADEB19C11B0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB19C1FF0 00000000 00000000 00000000 61BD200C [............. .a]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 0
 unformatted: 0 total: 64 first useful block: 6
 owning instance : 1
 instance ownership changed at 04/01/2013 18:55:06
 Last successful Search 04/01/2013 18:55:06
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

Extent Map Block Offset: 4294967295
 First free datablock : 64
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 290021638.140
 Flag: 0x00000020 (OBJD/-/-/-/-/-)
 Inc #: 0 Objd: 314978
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00100 Length: 64 Offset: 0

0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:Metadata 5:Metadata 6:FULL 7:FULL
 8:FULL 9:FULL 10:FULL 11:FULL
 12:FULL 13:FULL 14:FULL 15:FULL
 16:FULL 17:FULL 18:FULL 19:FULL
 20:FULL 21:FULL 22:FULL 23:FULL
 24:FULL 25:FULL 26:FULL 27:FULL
 28:FULL 29:FULL 30:FULL 31:FULL
 32:FULL 33:FULL 34:FULL 35:FULL
 36:FULL 37:FULL 38:FULL 39:FULL
 40:FULL 41:FULL 42:FULL 43:FULL
 44:FULL 45:FULL 46:FULL 47:FULL
 48:FULL 49:FULL 50:FULL 51:FULL
 52:FULL 53:FULL 54:FULL 55:FULL
 56:FULL 57:FULL 58:FULL 59:FULL
 60:FULL 61:FULL 62:FULL 63:FULL
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 256 maxblk 256

Half empty block.

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00900 (643/2304)
scn: 0x008c.11496801 seq: 0x05 flg: 0x04 tail: 0x68012005
frmt: 0x02 chkval: 0xbc12 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00900 11496801 0405008C [ ........hI.....]
2ADEB19C1010 0000BC12 00000000 00000000 00000000 [................]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 0000001C 00000004 00000040 [............@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 0000001A 00000004 5159A0CF 5159A0CF [..........YQ..YQ]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000020 00000000 00000000 [.... ...........]
2ADEB19C10A0 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C10C0 0004CE63 114964A2 0000008C A0C00900 [c....dI.........]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 00001111 [................]
2ADEB19C1190 00000000 00000000 00000000 55155515 [.............U.U]
2ADEB19C11A0 55155515 55155515 55555555 00000000 [.U.U.U.UUUUU....]
2ADEB19C11B0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB19C1FF0 00000000 00000000 00000000 68012005 [............. .h]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 32
 unformatted: 28 total: 64 first useful block: 4
 owning instance : 1
 instance ownership changed at 04/01/2013 18:59:27
 Last successful Search 04/01/2013 18:59:27
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 26

 Extent Map Block Offset: 4294967295
 First free datablock : 4
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 290022562.140
 Flag: 0x00000000 (-/-/-/-/-/-)
 Inc #: 0 Objd: 314979
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00900 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:unformatted 5:unformatted 6:unformatted 7:unformatted
 8:unformatted 9:unformatted 10:unformatted 11:unformatted
 12:unformatted 13:unformatted 14:unformatted 15:unformatted
 16:unformatted 17:unformatted 18:unformatted 19:unformatted
 20:unformatted 21:unformatted 22:unformatted 23:unformatted
 24:unformatted 25:unformatted 26:unformatted 27:unformatted
 28:unformatted 29:unformatted 30:unformatted 31:unformatted
 32:FULL 33:75-100% free 34:75-100% free 35:75-100% free
 36:FULL 37:75-100% free 38:75-100% free 39:75-100% free
 40:FULL 41:75-100% free 42:75-100% free 43:75-100% free
 44:FULL 45:75-100% free 46:75-100% free 47:75-100% free
 48:FULL 49:75-100% free 50:75-100% free 51:75-100% free
 52:FULL 53:75-100% free 54:75-100% free 55:75-100% free
 56:75-100% free 57:75-100% free 58:75-100% free 59:75-100% free
 60:75-100% free 61:75-100% free 62:75-100% free 63:75-100% free
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 2304 maxblk 2304

Any other block not change after drop or truncate than first block.

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00500 (643/1280)
scn: 0x008c.1149678a seq: 0x18 flg: 0x04 tail: 0x678a2018
frmt: 0x02 chkval: 0xad71 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00500 1149678A 0418008C [ ........gI.....]
2ADEB19C1010 0000AD71 00000000 00000000 00000000 [q...............]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 00000000 00000004 00000040 [............@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000040 5159A0CF 5159A0CF [....@.....YQ..YQ]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000010 00000000 00000000 [................]
2ADEB19C10A0 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C10C0 0004CE63 114964A2 0000008C A0C00500 [c....dI.........]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 11111111 [................]
2ADEB19C1190 11111111 11111111 11111111 11111111 [................]
2ADEB19C11A0 11111111 11111111 11111111 00000000 [................]
2ADEB19C11B0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB19C1FF0 00000000 00000000 00000000 678A2018 [............. .g]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 16
 unformatted: 0 total: 64 first useful block: 4
 owning instance : 1
 instance ownership changed at 04/01/2013 18:59:27
 Last successful Search 04/01/2013 18:59:27
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 64
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 290022562.140
 Flag: 0x00000000 (-/-/-/-/-/-)
 Inc #: 0 Objd: 314979
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00500 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:FULL 5:FULL 6:FULL 7:FULL
 8:FULL 9:FULL 10:FULL 11:FULL
 12:FULL 13:FULL 14:FULL 15:FULL
 16:FULL 17:FULL 18:FULL 19:FULL
 20:FULL 21:FULL 22:FULL 23:FULL
 24:FULL 25:FULL 26:FULL 27:FULL
 28:FULL 29:FULL 30:FULL 31:FULL
 32:FULL 33:FULL 34:FULL 35:FULL
 36:FULL 37:FULL 38:FULL 39:FULL
 40:FULL 41:FULL 42:FULL 43:FULL
 44:FULL 45:FULL 46:FULL 47:FULL
 48:FULL 49:FULL 50:FULL 51:FULL
 52:FULL 53:FULL 54:FULL 55:FULL
 56:FULL 57:FULL 58:FULL 59:FULL
 60:FULL 61:FULL 62:FULL 63:FULL
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 1280 maxblk 1280

 

truncate table system.mczim_test_block;
alter system checkpoint;

 

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00500 (643/1280)
scn: 0x008c.1149678a seq: 0x18 flg: 0x04 tail: 0x678a2018
frmt: 0x02 chkval: 0xad71 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00500 1149678A 0418008C [ ........gI.....]
2ADEB19C1010 0000AD71 00000000 00000000 00000000 [q...............]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 00000000 00000004 00000040 [............@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000040 5159A0CF 5159A0CF [....@.....YQ..YQ]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000010 00000000 00000000 [................]
2ADEB19C10A0 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C10C0 0004CE63 114964A2 0000008C A0C00500 [c....dI.........]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 11111111 [................]
2ADEB19C1190 11111111 11111111 11111111 11111111 [................]
2ADEB19C11A0 11111111 11111111 11111111 00000000 [................]
2ADEB19C11B0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB19C1FF0 00000000 00000000 00000000 678A2018 [............. .g]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 16
 unformatted: 0 total: 64 first useful block: 4
 owning instance : 1
 instance ownership changed at 04/01/2013 18:59:27
 Last successful Search 04/01/2013 18:59:27
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 64
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 290022562.140
 Flag: 0x00000000 (-/-/-/-/-/-)
 Inc #: 0 Objd: 314979
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00500 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:FULL 5:FULL 6:FULL 7:FULL
 8:FULL 9:FULL 10:FULL 11:FULL
 12:FULL 13:FULL 14:FULL 15:FULL
 16:FULL 17:FULL 18:FULL 19:FULL
 20:FULL 21:FULL 22:FULL 23:FULL
 24:FULL 25:FULL 26:FULL 27:FULL
 28:FULL 29:FULL 30:FULL 31:FULL
 32:FULL 33:FULL 34:FULL 35:FULL
 36:FULL 37:FULL 38:FULL 39:FULL
 40:FULL 41:FULL 42:FULL 43:FULL
 44:FULL 45:FULL 46:FULL 47:FULL
 48:FULL 49:FULL 50:FULL 51:FULL
 52:FULL 53:FULL 54:FULL 55:FULL
 56:FULL 57:FULL 58:FULL 59:FULL
 60:FULL 61:FULL 62:FULL 63:FULL
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 1280 maxblk 1280

 

drop table system.mczim_test_block;
alter system checkpoint;

 

Block dump from disk:
buffer tsn: 632 rdba: 0xa0c00500 (643/1280)
scn: 0x008c.1149678a seq: 0x18 flg: 0x04 tail: 0x678a2018
frmt: 0x02 chkval: 0xad71 type: 0x20=FIRST LEVEL BITMAP BLOCK
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00002ADEB19C1000 to 0x00002ADEB19C2000
2ADEB19C1000 00008220 A0C00500 1149678A 0418008C [ ........gI.....]
2ADEB19C1010 0000AD71 00000000 00000000 00000000 [q...............]
2ADEB19C1020 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C1040 00000000 00000000 00000000 00000004 [................]
2ADEB19C1050 FFFFFFFF 00000000 00000004 00000040 [............@...]
2ADEB19C1060 00010001 00000000 00000000 00000000 [................]
2ADEB19C1070 00000000 00000040 5159A0CF 5159A0CF [....@.....YQ..YQ]
2ADEB19C1080 00000000 00000000 00000000 00000000 [................]
2ADEB19C1090 A0C00104 00000010 00000000 00000000 [................]
2ADEB19C10A0 00000000 00000000 00000000 00000000 [................]
 Repeat 1 times
2ADEB19C10C0 0004CE63 114964A2 0000008C A0C00500 [c....dI.........]
2ADEB19C10D0 00000040 00000000 00000000 00000000 [@...............]
2ADEB19C10E0 00000000 00000000 00000000 00000000 [................]
 Repeat 9 times
2ADEB19C1180 00000000 00000000 00000000 11111111 [................]
2ADEB19C1190 11111111 11111111 11111111 11111111 [................]
2ADEB19C11A0 11111111 11111111 11111111 00000000 [................]
2ADEB19C11B0 00000000 00000000 00000000 00000000 [................]
 Repeat 227 times
2ADEB19C1FF0 00000000 00000000 00000000 678A2018 [............. .g]
Dump of First Level Bitmap Block
 --------------------------------
 nbits : 4 nranges: 1 parent dba: 0xa0c00104 poffset: 16
 unformatted: 0 total: 64 first useful block: 4
 owning instance : 1
 instance ownership changed at 04/01/2013 18:59:27
 Last successful Search 04/01/2013 18:59:27
 Freeness Status: nf1 0 nf2 0 nf3 0 nf4 0

 Extent Map Block Offset: 4294967295
 First free datablock : 64
 Bitmap block lock opcode 0
 Locker xid: : 0x0000.000.00000000
 Dealloc scn: 290022562.140
 Flag: 0x00000000 (-/-/-/-/-/-)
 Inc #: 0 Objd: 314979
 --------------------------------------------------------
 DBA Ranges :
 --------------------------------------------------------
 0xa0c00500 Length: 64 Offset: 0

 0:Metadata 1:Metadata 2:Metadata 3:Metadata
 4:FULL 5:FULL 6:FULL 7:FULL
 8:FULL 9:FULL 10:FULL 11:FULL
 12:FULL 13:FULL 14:FULL 15:FULL
 16:FULL 17:FULL 18:FULL 19:FULL
 20:FULL 21:FULL 22:FULL 23:FULL
 24:FULL 25:FULL 26:FULL 27:FULL
 28:FULL 29:FULL 30:FULL 31:FULL
 32:FULL 33:FULL 34:FULL 35:FULL
 36:FULL 37:FULL 38:FULL 39:FULL
 40:FULL 41:FULL 42:FULL 43:FULL
 44:FULL 45:FULL 46:FULL 47:FULL
 48:FULL 49:FULL 50:FULL 51:FULL
 52:FULL 53:FULL 54:FULL 55:FULL
 56:FULL 57:FULL 58:FULL 59:FULL
 60:FULL 61:FULL 62:FULL 63:FULL
 --------------------------------------------------------
End dump data blocks tsn: 632 file#: 643 minblk 1280 maxblk 1280
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