INITIAL_EXTENT for partitions

Hello listers,

I'm seeing something I don't understand. The database I'm analyzing was mainly created in the Oracle 8 days, so perhaps that is key.

As far as I can tell from the official docs, wherever INITIAL_EXTENT appears in the data dictionary (user_tables, user_tab_partitions, user_tab_supartitions, etc.), it shows the size, in bytes, of the initial extent.

Most of the tables in the db I'm looking at have an INITIAL_EXTENT set to 64K or 128K. The subpartitions also show an INITIAL_EXTENT of 64K (the default of the tablespace). But as I query user_tab_partitions, the INITIAL_EXTENT is "2" or "4" or null. As I look at user_part_tables, there too, for DEF_INITIAL_EXTENT, I see DEFAULT (which are the blank ones in user_tab_partitions), and 2 and 4.

I tried to replicate that with a test partitioned table, with the INITIAL set to 1, 2, 3, and 100, but in each case got an INITIAL_EXTENT of 32K (2 times my block size).

How on earth did I get 2 and 4 bytes as the INITIAL_EXTENT? I'm guessing you used to be able to enter INITIAL as a multiple of the block size, and the number I'm seeing is a holdover from pre-8i days, but I don't recall that ever being the case.

I doubt it matters as user_extents reports each subpartition at 64K bytes, no matter what initial_extent says in the dict views.

Just curious.

--

bill coulam
bcoulam_at_gmail.com

--

http://www.freelists.org/webpage/oracle-l Received on Thu Oct 27 2005 - 17:28:50 CDT