Re: segment header block

segment header block dump

buffer dba: 0x24000922 inc: 0x00000635 seq: 0x00000007

       ver: 1 type: 5=data segment header
==> type block type.

    nfl = 1, nfb = 1
==> nfl no free list
==> nfb no freelist groups ?

  ext ctl:: nex: 1 cex: 0 ces: 4  cbk: 2
lock value: u
==> nex number of extents allocated in the extent table (below)
==> cex current extent )
==> cb current block in current extent ) high water mark
==> ces current extent size (blocks)

==> extent table:

  ext tbl:: nbk: 4 dba: 0x24000923
==> nbk number of blocks available in the extent
  nb: the first extent has the segment header allocated from it

      this is really a 5 block extent (block 1 is seg hdr)
==> dba dba of first block in the extent

==> free list

  seg lst:: flg: used lhd: 0x24000924 ltl: 0x24000924
==> lhd head dba of free list
==> ltl tail dba of free list

==> nb: not all blocks in an extent are formatted if not yet used.
==> only those on the free list. blocks in the last extent and not
==> on the freelist may contain all zeroes

"Fredrik" <nospam_at_allowed.localhost> wrote in message news:bG_28.175$JV3.218_at_news2.bredband.com...

> Hi all
> Couldn't find much about this block class on the 'net... Just wondering
> what does it contain (segment freelist only for table or index
> segments?) and what instances are there when Oracle needs it? Version
> dependency (7-9)?
>
> Regards
> Fredrik
>
>