Re: What use is OCP? they did it again!

"mario" <mario_jvn_at_yahoo.it> wrote in message news:b84ce0d2.0211200929.85ed698_at_posting.google.com...
> From the last issue (November/December 2002) of
> Oracle Magazine, page 134:
>
> " Select two characteristics of locally managed tablespaces:
>
> A. extents are managed by the data dictionary.
>
> B. a bitmap in the datafile keeps track of the free
> or used status of blocks (sic!) in the datafile.
>
> C. Each segment stored in the tablespace can have a
> different storage clause.
>
> D. no coalescing is required.
>
> E. UNDO is not generated when allocation or
> deallocation of extents occurs.
>
> For locally managed tablespaces, the correct answers
> are B (sic!), D and E. "
>
> Each bit in the 64K bitmap corresponds to one extent in the file,
> and not, as stated, a single block.

Hi Mario,

Actually you are both right.

If a LMT has a uniform size, then yes, all bits correspond to an extent (as all extents must be of the same size)

However, if the LMT is autoallocate, then it can have a number of difference extent sizes, when can appear anywhere within the tablespace. Therefore in this case, each bit does indeed correspond to a block and Oracle searches for a range of bits that corresponds to the required extent size. It makes the bitmap less efficient as a result but you can still fit a mamma of a lot of bits in the bitmaps initially allocated.

All that said, answer B may or may not be correct and it's an ambiguity that's makes the question a bit stinky.

Cheers

Richard
>
>
> Mario from Rome
Received on Thu Nov 21 2002 - 08:37:59 CST