Coalescing extens in oracle 9i is mandatary or not

Question

hello
for our database we r using extent management local,segment space manegement
auto will SMON coalesces the freespace or not
please help me

Answer 1

Let's go back to the time when coalescing was the only way to add more free space when two or more adyacent extents were just freed.
SMON performed the action of periodically coalesce space, a command:
ALTER TABLESPACE tsname COALESCE;
forced the execution of coalescing.
Revisiting the internals of the coalesce behaviour:
Every five minutes it looked through the free extent table (sys.fet$) to see if there were any adjacent free extents that could be coalesced into a single extent, and on every 25th cycle (i.e. every two hours and five minutes) it looked at the segment table (sys.seg$) to see if there were any temporary segments that need to be eliminated.
Once the locally manged tablespaces were created there was the need to aceess SYS.FET$ nor SYS.SEG$ no more. Conclusion, this coalesce behaviour remains valid only to dictionary managed tablespaces, no matter what.