> -----Original Message----- > From: Diogo Biazus [mailto:diogo@ikono.com.br] > Sent: Wednesday, March 31, 2004 11:02 AM > To: Dann Corbit > Cc: pgsql-general@postgresql.org > Subject: Re: Wich hardware suits best for large > full-text indexed databases > > > Dann Corbit wrote: > > >I see that only table documentos has a unique index. Is it > really so > >that none of the other tables has a key to uniquely identify > a record? > >Perhaps the others have a unique attribute but it was never declared > >when forming the index? > > > I thougth that a primary key would create a unique index implictly. Yes, I believe that is correct also. It is strange that it is not reflected in the schema. > >I do not remember which version of PostgreSQL you are using, > but there > >is now a CLUSTER command. Now, I am speaking with my experience in > >other database systems, and so perhaps the PostgreSQL group > may find it > >necessary to correct me. I have only recently began working with > >PostgreSQL versions beyond 7.1.3 which had no cluster command (or at > >least I was not aware of one). In other database systems, a > clustered > >index is incredibly valuable. In fact, a unique, clustered index is > >always a silver bullet to marvelous performance. Perhaps > some of the > >experts can give measurements as to the effectiveness of > clustering in > >PostgreSQL. Here is the link for the cluster documentation: > >http://www.postgresql.org/docs/current/static/sql-cluster.html > > > >>From the description, clustering is expensive and your tables are > >>large. > >So it should be an infrequent operation. > > > > > Sure, my pgsql is version 7.3.4 (I was obviosly mistaken when I wrote > 7.4.3 in a previous email) I used to do clustering in some > tables, but > is a expensive operation as said... Can you send me an unload of your schema? I will pull it into ERWin/Erx and have a look at the model. It is hard for me to picture things unless I can see them visually. ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
