If the number of extents allocated to a segment is large (lets say 5000) will there be an impact on performance - I am asking about a segment which is in a locally managed tablespace with uniform extent size. I understand that this is a problem in the case of dictionary managed tablespace.
Allocating extents to an object depends on the importance of the object.Since the object is getting used more keep maxextents very high otherwise low.
In case of dictionary managed tablespace for extent allocation ...Oracle will have to update the data dictionary but if ur object is in locally managed tablespace then there is no write to data dictionary for extents allocation.The tablespace which houses the object is responsible to maintain information about the extent allocation.
In locally managed tablespace all information about extents is kept in bitmap table in that tablespace only...so writes to data dictionary is reduced.