Re: Locally Managed Tablespaces ... again!!!

"Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote:
> <ctcgag_at_hotmail.com> wrote in message news:20030116123115.542
> >
> > I've seen the table/index read serialization/contention done to death,
> > but haven't seen much here about table/index write
> > serialization/contention.
> >
> > The only write contention into datafiles should be on DBWR, so the fact
> > that the blocks were dirtied in serial should no longer matter when
> > DBWR gets around to writing them, would it?
> >
> > Xho
>
> Why? You think a single DBWR suddenly acquires the ability to perform
> multiple writes simultaneously?

No, I think the DBWR could have that ability, depending on how/if the OS/platform supports asynchronous I/O. But I think whether DBWR has this ability or not is independent of whether the blocks were dirtied in parallel or in serial.

> Or that multiple DBWx's deliberately parallelize (and thus create
> contention) writes to indexes and tables?

If the index and the table are on the same spindle, deliberation is not required for this contention to arise.

> Like, DBWR has a clue *what*
> it's writing?

My point exactly.

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