blockdump-8.x Data Segment Header in Oracle

Oracle
subject:qref:blockdump-8.x Data Segment Header in Oracle creation date:25-apr-2000 CACHE block:see note:47132.1 type : 0x10=data SEGMENT header-unlimitedextent control:extent HEADER:: spare1:0 space2:0 #extents: #blocks: 1429 Last Map 0x00000000 #maps: 0 offset:4128 highwater:: 0x020004d0 ext#: blk#: 275 ext size:475 #blocks in seg. HDR ' s freelists:5 #blocks below:1229 mapblk 0x00000000 offset:12 unlocked==> spare1:this field is no longer used (O LD inc#, now always 0) ==> space2:this field are no longer used (old ts#, now always 0) ==> #extents: Number of extent s allocated to segment==> #blocks: number of blocks allocated to segment==> last map:address the last extent map Blo CK 0 If extent map is entirely in the segment header==> #maps: Number of extent map block==> offset:offset to end O F extent Map==> HWM dba:address of block in Highwater mark==> ext#: HWM extent number relative to segment==> BLK #: HWM block number within EXTENT==&GT Ext SIZE:HWM Extent size (in blocks) ==> #blocks in seg. HDR ' s freelists:number of blocks in SEG. HDR ' s free list ==> #blocks below:number of blocks below hwm==> mapblk Dba:dba to extent map block containing HWM Extent is 0 if HWM are in the segment header==> Offset:offset within extent map block is the ext# if HWM-in segment Header==> Locked by:if Locked by a transaction, the XID is Displayedextent map:map Header:: Next 0x00000000 #extents: obj#: 12141 flag:0x40000000 0x02000003 length:4 0x02000007 length:5 0x0200000c length:10 0x02000016 length:15 000025 length:20 0x02000039 length:30 0x02000057 length:45 0x02000084 length:65 0x020000c5 length:95 0x02000124 lengt h:140 0x020001b0 length:210 0x02000282 length:315 0x020003bd length:475 Map header:==> next dba:address of next ex Tent map block==> #extents: Number of extents in-extent map block==> obj#: Object ID for this segment==> FLA G:flag to Mark's version of segment heAder is 2 if the segment header is V8map extent:==> dba:dba of extent==> length:number to blocks in Extentfree LIS T:NFL = 1, NFB = 1 Typ = 1 nxf = 0 SEG LST:: flg:used lhd:0x020004cb ltl:0x020004cf Segment header:==> of free lists/block==> nfb:number of free list blocks + segment header==> typ:block type ==> nxf:number of tra Nsaction free listssegment list:==> flg:flag USED or unused the free list==> lhd:head to free list==> ltl:tail of free list