Re: Index Scans become Seq Scans after VACUUM ANALYSE

Curt Sampson wrote:
> On Mon, 24 Jun 2002, Tom Lane wrote:
>
> > There are a lot of other things we desperately need to spend time
> > on that would not amount to re-engineering large quantities of OS-level
> > code. Given that most Unixen have perfectly respectable disk management
> > subsystems, we prefer to tune our code to make use of that stuff, rather
> > than follow the "conventional wisdom" that databases need to bypass it.
> > ...
> > Oracle can afford to do that sort of thing because they have umpteen
> > thousand developers available. Postgres does not.
>
> Well, Oracle also started out, a long long time ago, on systems without
> unified buffer cache and so on, and so they *had* to write this stuff
> because otherwise data would not be cached. So Oracle can also afford to
> maintain it now because the code already exists.

Well, actually, it isn't unified buffer cache that is the issue, but
rather the older SysV file system had pretty poor performance so
bypassing it was a bigger win that it is today.

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