RE: Checkpoint Duration - HDR - Sync/Async
Thanks Art and Alexey,
your answers combined clarified
my problem.
Now i think that my problem could be avoided
if there is a way of telling Informix that
my DSS querys doesn't have priority,
I mean I don't care if these querys executed on
my secondary server takes a lot of more time, as long
as my checkpoint duration does not get affected.
I use dbaccess for executing the querys,
is there a way of doing this ?
Thanks in advance
Regards
-----Mensaje original-----
De: Art S. Kagel [mailto:kagel@bloomberg.net]
Enviado el: Martes, 07 de Octubre de 2003 09:09 a.m.
Para: Francisco Roldan
Asunto: RE: Checkpoint Duration - HDR - Sync/Async
[This is an email copy of a Usenet post to "comp.databases.informix"]
On Mon, 06 Oct 2003 18:12:36 -0400, Francisco Roldan wrote:
Hi.
> Thanks Alexey,
> i really appreciate your help
>
> I think that the dss query was taking
> disk resources, but regardless of
> cpu or disk resources, I think that
> when a ckeckpoint occurs, Informix stops running any query (even
> already started querys) and doesn't execute new ones, and then execute
> the checkpoint, am i right?
<SNIP>
Checkpoints officially only block threads that require a critical section,
ie those updating pages. Unofficially there is/was a design flaw at least
through 7.30 wherein any non-critical threads running in CPU VP #1 were
suspended while that VP managed the disk flushes, roughly for the first half
of the checkpoint duration. This was supposed to be addressed in 7.31 and
9.21 but I do not know if the problem was ever solved. Non-critical threads
running on other CPU VPs are not affected.
Art S. Kagel
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