Re: Faster selecting tablespace fill level
Date: Thu, 25 Feb 2010 20:37:59 +0100
Generally speaking, whenever you have performance isues with DBA views, the best thing to do is to check in the catalog script how they were defined, peek into sql.bsq, which is fortunately very well commented, to get a better understanding of the underlying tables, and to rewrite your queries from scratch. The problem with DBA_ views is that they are mega joins, which becomes a problem when you join one DBA view to another (usually on unindexed columns) or aggregate them enthusiastically. In your case, start with SYS.SEG$, aggregate by ts# and join on SYS.TS$ when you have all your figures, not before, and you should be happy with performance.
Martin Klier wrote:
> Dear list,
> is there a way to get the results from the select below, in a more
> peaceful way?
> An execution plan on that piece of SQL opens a glance into performance
> issues deep and deeper. (My 10g DB calculates cost of over 12k, and 530k
> buffer gets).