I was wondering if someone is using locally managed tablespaces
in a VLDB production environment ( from 40-60Gb up to 3-4 terabytes,
about 400-5000 tables , 100-2000 tablespaces), because I cannot simulate and perform
tests with this feature in a large environment.
Any problems or suggestions with LMT?
Thanks in advance
LMT do not use the data dictionary to track free space and extent allocation,they buy itself maintain info for blocks or sets of blocks contained within.. so you may have a higher performance. They also eliminate the need to periodically coalesce free space...will go well for temporary tablespaces for es...
I know of several DBA's that will ONLY have LMT in their databases (except, of course, for system). They claim huge performance increases with growing databases.
Few limitations with LMT:
1) Minimum datafile size is 64K.
2)While creating datafile, be sure of extent policy.
3)Do not drop in read only mode.
4)Rollback segments are first created on dictionary tablespace and then coverted to LMT, besure compatible parameter is 8.1.6.
otherwise, Full export will give u problems.
5)Next extent,pctincrease parameters do not work.
6) Cannot change next parameteronce objects are created.
for point 4, you first create a dummy RBS if you dont have any RBS, once you have a dummy RBS you can create a LMT for your *REAL* RBS. You dont need to convert
for point 5 and 6, these are not limitations these are features. When the extent size is uniform there is not point alter object´s storage and with LMT we get uniform extent sizes