Re: GiST indexing problems...

David,

could you provide more info (scheme, query, postgresql version)

Regards,

Oleg
On Sat, 5 May 2001, David McWherter wrote:

>
> I've been doing some research work using the GiST indexes,
> but I persistently develop a problem where the system doesn't
> make use of the indexes during the execution of a query. If
> I use the examples provided here:
>
> http://wit.mcs.anl.gov/~selkovjr/pg_extensions/
>
> For instance, and I place an elog( DEBUG, "functionname" )
> in each of the GiST accessor functions, I can witness when
> the database is making use of the index. During the construction
> of the index, I never have a problem, although during query
> execution, it seems that my indices aren't getting used at
> all, and the database is simply searching through all of
> the entries in the database.
>
> This is a terribly frustrating problem that I encountered
> once before, but which mysteriously went away after fiddling
> with the problem for a while. This time, the problem isn't
> going away, however. When I trace through the postgres
> application I can see that it at least examines the opclass
> for my specialized data types, and detects that there exists
> an index that could be used, but it seems to decide not to
> make use of it regardless.
>
> Is there an easy way that I can force the use of an index
> during a query?
>
> -David
>
> ----------------------[=========]------------------------
> David T. McWherter udmcwher(at)mcs(dot)drexel(dot)edu
>
> vdiff
> =====
> /vee'dif/ v.,n. Visual diff. The operation offinding
> differences between two files by {eyeball search}. Theterm
> `optical diff' has also been reported, and is sometimes more
> specifically used for the act of superimposing two nearly identical
> printouts on one another and holding them up to a light to spot
> differences. Though this method is poor for detecting omissions in
> the `rear' file, it can also be used with printouts of graphics, a
> claim few if any diff programs can make. See {diff}.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo(at)postgresql(dot)org
>

Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83