Script to check possible resize value for a datafile

Sometimes, we will be getting a requirement to resize the datafile to a lower value in order to create some space in the mount point (file system). In that case, how we would know which datafile and to what size we can lower it? The below script will helps us in that.

###################################################

SCRIPT TO CALCUTE POSSIBLE RESIZE VALUE

###################################################

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(+)

/

 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_temp_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(+)

/

 column cmd format a75 word_wrapped

 select ‘alter database datafile ”’ || file_name || ”’ resize ‘ ||

ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) || ‘m;’ cmd

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(+)

and ceil( blocks*&&blksize/1024/1024) –

ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) > 0

/

select ‘alter database tempfile ”’ || file_name || ”’ resize ‘ ||

ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) || ‘m;’ cmd

from dba_temp_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(+)

and ceil( blocks*&&blksize/1024/1024) –

ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) > 0

/