Find free buffers in buffer cache

Question

hi guys,
V$BH view contains the information about each block that is present in the buffer cache. can any one please tell me how to find the information about the free buffers??

Answer 1

Mark D Powell wrote:
select decode(state,0,'Free',
1,'Read and Modified',
2,'Read and Not Modified',
3,'Currently being Modified',
'Other'
) buffer_state,
count(*)  buffer_count
from    sys.xx_bh
group by decode(state,0,'Free',
1,'Read and Modified',
2,'Read and Not Modified',
3,'Currently being Modified',
'Other'
Provided the OP figures out that xx_bh is probably a view defined by sys on top of x$bh this will get him the number of free buffers - which may be what he wants - but apart from that your query is at least 10 years short of complete, and the decode() of state 3 is definitley wrong.
The decode of x$bh.state for 10g is:
     decode(state,
          0,'free',
          1,'xcur',
          2,'scur',
          3,'cr',
          4,'read',
          5,'mrec',
          6,'irec',
          7,'write',
          8,'pi',
          9,'memory',
          10,'mwrite',
          11,'donated'
     ), and for 11g it is:
     decode(state,
           0, 'free',
           1, 'xcur',
           2, 'scur',
           3, 'cr',
           4, 'read',
           5, 'mrec',
           6, 'irec',
           7, 'write',
           8, 'pi',
           9, 'memory',
          10, 'mwrite',
          11, 'donated',
          12, 'protected', 
          13, 'securefile',
          14, 'siop',
          15, 'recckpt',
          16, 'flashfree', 
          17, 'flashcur',
          18, 'flashna'
     ), (At least, that was the last time I looked - they may have changed again in 10.2.0.5 and 11.2.0.2)
Regards
Jonathan Lewis