Below query to find out possible savings from each data files of Database
set verify off
column file_name format a50 word_wrapped
column smallest format 999,990 heading "Smallest|Size|Poss."
column currsize format 999,990 heading "Current|Size"
column savings format 999,990 heading "Poss.|Savings"
break on report
compute sum of savings on report
column value new_val blksize
select value from v$parameter where name = 'db_block_size';
/
select file_name,
ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) smallest,
ceil( blocks*&&blksize/1024/1024) currsize,
ceil( blocks*&&blksize/1024/1024) -
ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) savings
from dba_data_files a,
( select file_id, max(block_id+blocks-1) hwm
from dba_extents
group by file_id ) b
where a.file_id = b.file_id(+) order by savings desc
/
Script from notes to generate the queries to resize the data files:
select 'alter database datafile'||' '''||file_name||''''||' resize '||round(highwater+2)||' '||'m'||';' from (
select /*+ rule */
a.tablespace_name,
a.file_name,
a.bytes/1024/1024 file_size_MB,
(b.maximum+c.blocks-1)*d.db_block_size/1024/1024 highwater
from dba_data_files a ,
(select file_id,max(block_id) maximum
from dba_extents
group by file_id) b,
dba_extents c,
(select value db_block_size
from v$parameter
where name='db_block_size') d
where a.file_id= b.file_id
and c.file_id = b.file_id
and c.block_id = b.maximum
order by a.tablespace_name,a.file_name);
