Re: Some basic dba_free_space stuff

Basically, Oracle creates a free space extent one for one for every extent of a table when you DROP the table. Deleting rows has no effect on dba_ffree space.

The ALTER TABLE ____ DEALOCATE UNUSED also returns extents to dba_free _space.

The TRUNCATE TABLE _____ DROP STORAGE also returns extents to dba_free_space.

Doug Cowles wrote:

> Just some basic questions about dba_free_space.
> I have a tablespace, which in dba_free_space shows some "chunks" of free
> space.
> I'm wondering about the size of the chunks. If I delete a row for
> example, That one
> small chunk of space surely isn't freed - so how does Oracle decide that
> a "chunk"
> of space is free, after a certain number of deletes, does it do it's own
> coalescing
> for example? There's a 400K block of space in the below output for
> example.
> How did a "chunk" that size get freed?
>
> Output is
> tablespace file_id block_id
> bytes blocks
> INTFD2 15 27
> 14540800 1775
> INTFD2 15 8267
> 409600 50
> INTFD2 15 8537 34930688
> 4264
> INTFD2 15 4187
> 7372800 900
Received on Wed Jun 02 1999 - 22:43:27 CDT