I have an old database with Dictionary Managed
Tablespaces and they are moving to locally managed tablespaces
(LMT). What are the benefits of LMT over DMT tablespaces?
know about the Oracle SGA and PGA, but I also hear about a RAM
region called the User Global Area (UGA). What is the UGA and
how does it differ from the Program Global Area (PGA)?
Answer: The main benefit of an LMT is that the
data dictionary control structures for the tablespace extent
management move from inside the data dictionary (where it's a single
point of contention) into the tablespace header blocks, where there
is less contention.
LMT's are not the default in Oracle and they also
work with other tablespace features such as Automatic Segment Space
Management (ASSM). See my notes
the benefits of LMT with ASSM