Oracle: X$BH

select
   count(*) over () cnt,
   bh.indx                                 bh_indx,
   -------------------
   bh.tch                                  touch_count,  -- How often the buffer was accessed.
                                                         -- This number is increased each time a buffer is accessed (MOS Note 136312).
                                                         -- Buffers with high tch numbers are considered «hot blocks» and are expected to be at the end of the LRU list.
                                                         -- See also the SGA variable kcbatt_
   -------------------
   decode(bh.lru_flag,                                   -- This number/flag is also not exposed in v$bh
    0, 'MID',
    2, 'LRU',
    4, 'AUX',
    8, 'HOT',
    '???'
   )                                       lru
   bh.inst_id,
   file#,
   dbablk                                  block#,
   class,
-- obj,   
   ob.name                                 obj_name,
   ow.name                                 obj_owner,
   bp.bp_name                              buffer_pool,
   case when bh.tim != 4294967295 then
        date'1970-01-01'+ bh.tim/24/60/60
   end                                     last_touch_time,
   decode(state,
        0,'free'      , -- Not used
        1,'xcur'      , -- Exclusive (current?)
        2,'scur'      , -- Shared current
        3,'cr'        , -- Consistent read
        4,'read'      , -- Being read into buffer
        5,'mrec'      , -- Media recovery mode
        6,'irec'      , -- Instance recovery mode
        7,'write'     ,
        8,'pi'        , -- Past image (RAC mode)
        9,'memory'    ,
       10,'mwrite'    ,
       11,'donated'   ,
       12,'protected' ,
       13,'securefile',
       14,'siop'      ,
       15,'recckpt'   ,
       16,'flashfree' ,
       17,'flashcur'  ,
       18,'flashna'
    )                                      status_decoded,
/*  0                   xnc,
    0                   forced_reads,
    0                   forced_writes, */
   bh.fp_whr,    
   bh.mode_held,
   bh.changes,
   count(*) over (
      partition by bh.dbarfil,
                   bh.dbablk
   )                                       clone_cnt,
   kc.indx                                 kc_indx,
   kc.dbwr_num                             kc_dbwr_num,
   bh.le_addr,
   le_id1          lock_element_name,
   le_id2          lock_element_class,
   decode(bitand(bh.flag,     1),0,'N','Y') dirty,
   decode(bitand(bh.flag,    16),0,'N','Y') temp,
   decode(bitand(bh.flag,  1536),0,'N','Y') ping,
   decode(bitand(bh.flag, 16384),0,'N','Y') stale,
   decode(bitand(bh.flag, 65536),0,'N','Y') direct,
   decode(bitand(bh.flag,524288),0,'N','Y') fts,     -- buffer was read in full table scan (http://www.adp-gmbh.ch/ora/tuning/fts_blocks_in_cache.html)
   bh.flag2,
   bh.rflag,
   bh.sflag,
 -- 'N'    new,
   ts#,
   lobid,
   bitand(OBJ_FLAG, 240)/16   cachehint,
   decode(bitand(OBJ_FLAG, 48)/16,
        1, 'KEEP',
        2, 'NONE',
           'DEFAULT'
   )                                       flash_cache, 
   decode(
      bitand(OBJ_FLAG, 192)/64,
      1, 'KEEP',
      2, 'NONE',
         'DEFAULT'
   )                                       cell_flash_cache,
   bh.blsiz / 1024                         block_size_kb,
-- kc.blk_size,
   --
   bh.cr_xid_usn, bh.cr_xid_slt, bh.cr_xid_sqn,
   bh.cr_uba_fil, bh.cr_uba_blk, bh.cr_uba_rec,
   --
   bh.cr_sfl,
   bh.lrba_seq,
   bh.lrba_bno,
   bh.hsub_scn,
   --                                 bas / wrp
   bh.cr_scn_bas , bh.cr_scn_wrp,
   bh.fp_scn_bas , bh.fp_scn_wrp,
   bh.cr_cls_bas , bh.cr_cls_wrp,
   bh.hscn_bas   , bh.hscn_wrp,
   --                                 nxt/prv
   bh.us_nxt     , bh.us_prv,
   bh.wa_nxt     , bh.wa_prv,   
   bh.oq_nxt     , bh.oq_prv,
   bh.aq_nxt     , bh.aq_prv,
   --
   bh.nxt_hash   , bh.prv_hash,
   bh.nxt_repl   , bh.prv_repl,
   --
   bh.obj_flag,
   bh.cr_rfcnt,
   bh.shr_rfcnt,
   --
-- bh.hladdr,                                -- Hash-Latch address, used to join to v$latch_children
   lc.latch#                lc_latch         ,         -- Always 327?
   lc.child#                lc_child         ,
   lc.name                  lc_name          ,         -- Always 'cache buffer chains'?
   lc.wait_time             lc_wait_time     ,
   lc.gets                  lc_gets          ,
   lc.immediate_gets        lc_immediate_gets,
   lc.misses                lc_misses        ,
   lc.spin_gets             lc_spin_gets     ,
-- lc.*,
   --
   bh.cstate,
   bh.dirty_queue,
   bh.set_ds,
   bh.ba,
   bh.con_id
from
   x$bh             bh                                 join
   x$kcbwds         kc on bh.set_ds  = kc.addr         join
   x$kcbwbpd        bp on kc.pool_id = bp.bp_id   left join
   x$le             le on bh.le_addr = le.le_addr left join
   v$latch_children lc on bh.hladdr  = lc.addr    left join
   obj$             ob on bh.obj     = ob.obj#    left join
   user$            ow on ob.owner#  = ow.user#
-- where
--    state != 0
--    ob.owner# not in (0, 9) -- SYS, SYSTEM
order by
   lc.wait_time desc
-- tim desc
;

select
   count(*)                                                  cnt,
   count(distinct prv_hash) cnt_ph, count(distinct nxt_hash) cnt_nh,
   count(distinct prv_repl) cnt_pr, count(distinct nxt_repl) cnt_nr,
   count(distinct us_prv  ) cnt_pu, count(distinct us_nxt  ) cnt_nu,
   count(distinct wa_prv  ) cnt_pw, count(distinct wa_nxt  ) cnt_nw,
   count(distinct oq_prv  ) cnt_po, count(distinct oq_nxt  ) cnt_no,
   count(distinct aq_prv  ) cnt_pa, count(distinct aq_nxt  ) cnt_na
from
   x$bh;

select
   count(*),
   set_ds_dec,
   set_ds_dec + 264 set_ds_dec_
from (
   select to_number(set_ds, lpad('x', 16, 'x')) set_ds_dec from x$bh
)
group by
   set_ds_dec,
   set_ds_dec + 264
;