Re: How come my SELECT COUNT(1) takes so long...

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Tue, 6 Mar 2001 21:06:41 -0000
Message-ID: <983912929.6313.0.nnrp-09.9e984b29@news.demon.co.uk>

> > >> TOTAL Blocks 35840
> > >> TOTAL Bytes 146800640
> > >> UNUSED Blocks 420
> > >> UNUSED Bytes 1720320
> > >> Last used extent_file_id 30
> > >> Last used extent_block_id 312
> > >> Last used block with last extent (HWM) 2140

Actually there are 35,840 blocks in total, with the HWM just 42- from the top.
Indications are that this is 14 extents
of 2560 block each - so some thought has been paid to getting it right.

What if you had to do dirty block clean out on 35,000 blocks ? 20 blocks per second
seems a bit slow even if they all have to be written, but within the realms of possibility.

--
Jonathan Lewis
Yet another Oracle-related web site:  http://www.jlcomp.demon.co.uk

Practical Oracle 8i:  Building Efficient Databases
Publishers:  Addison-Wesley

Reviews at: http://www.jlcomp.demon.co.uk/book_rev.html



Van Messner wrote in message ...


>Hi Sybrand:

>

>    Even if he hits all 2000 blocks don't you think 1/2 hour seems awfully

>long?

>

Received on Tue Mar 06 2001 - 15:06:41 CST