Re: Synchronous writes & TEMP

Please re-read what I've written before replying -- the question has got nothing to do with asynchronous I/O.

VC

"Karsten Schmidt" <groups_at_karsten-schmidt.com> wrote in message news:c6711ac4.0405141113.715306a1_at_posting.google.com...
> What's the point in using async i/o for temp?
> you are using the temp tablespace from your session when you run out
> of ram (i.e. sort_area_size etc..)
>
> You can only continue processing when the write to temp is finished,
> and the memory is free. So if you were using async i/o to write to the
> temp segment, what would your session be doing while the write
> operation is ongoing? -- waiting for it to finished.
>
> Karsten
>
>
>
>
>
> boston103_at_hotmail.com (VC) wrote in message
news:<31e0625e.0405130945.54d00c58_at_posting.google.com>...
> > "VC" <boston103_at_hotmail.com> wrote in message
news:<MqIoc.39444$xw3.2544076_at_attbi_s04>...
> > > Does anybody know why Oracle uses synchronous writes while writing to
the
> > > temporary tablespace ? Presumably we do not care about data loss in
this
> > > case.
> > >
> > > Your thouhts are much appreciated.
> > >
> > > VC
> >
> > Probably I was being a little imprecise judging by lack of feedback.
> >
> > What I am asking here is why Oracle insists on executing synchronous
> > write operations whilst writing to the TEMP tablespace. A synchronous
> > write means such operation that does not return control to the caller
> > until the data is presumed to be safely on the disk. By contrast, a
> > non-synchronous write (the 'default') operation returns control as
> > soon as the data is transferred to the filesystem cache. The
> > rationale for executing synchronous writes against the data files and
> > redo logs is obvious.
> >
> > I believe (but I may be wrong since I checked only Solaris and Linux)
> > that writes to TEMP are synchronous regardless of the OS or Oracle
> > version.
> >
> > Please do not confuse synchronous writes with asynchronous I/O --
> > that's a different beast entirely. I am curious as to why exactly the
> > OS write system calls against TEMP are synchronous if data integrity
> > is not an issue, that's all.
> >
> > Thank you.
> >
> > VC
Received on Fri May 14 2004 - 14:18:32 CDT