Segments - Display segments with more than 20 extents and the next extent size 
--
--  Name: segments_many_extents.sql
--
--  Description: Segments - Display segments with more than 20 extents and the next extent size
--
--  Compatability: 7.3.x and above
--
--  Usage: @segments_many_extents
--
--
-- save SQL*Plus settings:
store set savesqlplus_settings.sql replace
-- set SQL*Plus settings:
set linesize 133
set pages 40
--

column owner format a20 heading "Owner"
column segment_name format a30 
column segment_type format a10

select  owner,
        segment_name,
        segment_type,
        bytes,
        extents,
        next_extent
from    sys.DBA_SEGMENTS
where   extents >= 20
order by owner,segment_name
;

--
-- restore SQL*Plus settings:
@savesqlplus_settings