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Re: does number of datafiles affects buffer related wait events?

Stephen Andert

2006-06-29

Replies:

I would guess that the difference in timing had more to do with the physical access time reduction due to striping across disks due to having multiple files.
 
Stephen

 
On 6/26/06, LS Cheng <exriscer@gmail.com> wrote:
Hi

I was wondering if anyone know if the number of datafiles would reduce cache buffer chains latch and buffer waits?

I have a insert process which inserts 16 million of rows in 30 seconds. The table it is inserting to is located at a tablespace with 16, 1GB each, datafiles (all located in same filesystem).

I ran the same insert in a tablespace with a single datafile (10GB) in the same filesystem as previous tablespace now the insert takes 2 minutes and 30 seconds and I observed quite a few buffer busy waits, free buffer busy waits and latch free (cache buffer chains) events.

I am not sure if more datafiles improved the I/O  or the event did not happen with more datafiles because with more datafiles the data blocks are better distributed?

LSC
 

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