Re: Oracle - best index

Thanks, we compute statistics every night.

Stefan

"Howard A Latham" <hlatham_at_dircon.co.uk> schrieb im Newsbeitrag news:b7QZ9.6$kG1.59873_at_news.nyc.globix.net...
> Have you computed statistics on the table?
> "Jens Meier" <jens.meier_at_ddr.de> wrote in message
> news:b18ibj$vb1st$1_at_ID-109621.news.dfncis.de...
> > Hi,
> >
> >
> >
> > can anyone help?
> >
> > The Reason:
> >
> > Table with more then 300.000 (and daily more) rows and round 20
Columns.
> >
> > DB : Oracle 8.17
> >
> > The Problem:
> >
> > Very slow searchresults, because we use different Searchterms to
extract
> > rows,
> >
> > -> not ever hits an index
> >
> > Sample
> >
> >
> >
> > ColumnA(PK) ColumnB ColumnC ColumnD ColumnE ColumnF
> >
> >
> >
> > ColumnA Unique
> >
> > ColumnB only 6 different entries
> >
> > ColumnC only 10 different entries
> >
> > ColumnD Date
> >
> > ColumnE only 6 different entries
> >
> > ColumnF only 50 different entries
> >
> >
> >
> > Sometimes we search with the exact ColumnA
> >
> > Sometimes we search with like %ColumnA
> >
> > Sometimes we use ColumnC ColumnD
> >
> > Sometimes we use ColumnD ColumnE ColumnF
> >
> > Sometimes we use %ColumnA ColumnD ColumnE ColumnF
> >
> > But sometimes we use ColumnD in a timerange
> >
> >
> >
> >
> >
> > I don't know which index is the best for this situation.
> >
> > (Which columns, Bitmap or normal index...)
> >
> >
> >
> >
> >
> > Now we have of course the PK as Index (standard)
> >
> > Then we have created many other combinations of columns as index,
> >
> > but the oracle optimizer doesn't match every time the best index, so we
> have
> > sometimes very high answer times.
> >
> >
> >
> > Can anybody help and give me some hints to perform the search?
> >
> >
> >
> > Thanks for helping
> >
> >
> >
> > Stefan
> >
> >
> >
> >
>
> Received on Wed Jan 29 2003 - 17:25:37 CET