Re: Inserts and row chaining

Chuck Hamilton (chuckh_at_dvol.com) wrote:

: According to the instructor in the DBA-1 class that I took, it won't
: spread a row across multiple blocks unless it has too. If the block
: has not reached the pctfree threshold, it'll insert it into another
: block. (i.e. It'll grab the free block in the extent, or allocate a
: new extent.)
 

: --
: Chuck Hamilton
: chuckh_at_dvol.com

Chuck, thanks for your reply. However, I am still a little unclear. Lets say I have a 100-byte row that I wish to insert and the next block on the freelist will exceed (or go under) the PCTFREE value in 75 bytes. My boss insists that Oracle will place 75 bytes into this block and 25 into the following block. I cannot believe Oracle would do that because we would have chained rows all over the place.

However, if it doesn't do that, what does it do ? Does it look throughout the freelist to find a block that won't cause that to happen ? A book I read said something about taking the block off the freelist, but it didn't say it would use it !!

Arrggh...

Thanks !

Brett
zgeist_at_ee.net Received on Thu Jan 16 1997 - 00:00:00 CST