Re: Performance (was: The New Slashdot Setup (includes MySql server))

> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > All the sequential catalog scans that return one row are gone. What has
> > not been done is adding indexes for scans returning more than one row.
>
> I've occasionally wondered whether we can't find a way to use the
> catcaches for searches that can return multiple rows. It'd be easy
> enough to add an API for catcache that could return multiple rows given
> a nonunique search key. The problem is how to keep the catcache up to
> date with underlying reality for this kind of query. Deletions of rows
> will be handled by the existing catcache invalidation mechanism, but
> how can we know when some other backend has added a row that will match
> a search condition? Haven't seen an answer short of scanning the table
> every time, which makes the catcache no win at all.

Good point. You can invalidate stuff, but how to find new stuff that
doesn't have a specific key?

--
Bruce Momjian | http://www.op.net/~candle
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026