Re: Performance Issues

[Dhanaraj M <Dhanaraj(dot)M(at)Sun(dot)COM>]

Thank you for your help. I found that an implicit index is created for 
the primary key in the current version. However, it is not done in 7.x 
version.


Mark Woodward wrote:

> > Dhanaraj M wrote:
> >    
> >
> > > I have the following doubts.
> > >
> > > 1. Does postgres create an index on every primary key?  Usually, queries
> > > are performed against a table on the primary key, so, an index on it
> > > will be very useful.
> > >      
> > Yes, a unique index is used to enforce the primary-key.
> >    
>
> Well, here is an interesting question that I have suddenly become very
> curious of, if you have a primary key, obviously a unique index, is it, in
> fact, use this index regardless of analyzing the table?
>
>
>  
>
> > > 2. If 'm executing a complex query and it takes 10 seconds to return the
> > > results -- it takes 10 seconds to execute the next time also.  I'm
> > > wondering if there's any kind of caching that can be enabled -- so, the
> > > next time it takes <10 seconds to return the results.
> > >      
> > Not of query results. Obviously data itself might be cached. You might
> > want to look at memcached for this sort of thing.
> >    
>
>
> I am looking at this string of posts and it occurs to me that he should
> run analyze. Maybe I'm jumping at the wrong point.
>