Re: CBO VS RULE

Two simple possibilities are -- the table is fairly small or most of the entries in the table have a that_ID = 5. In these two cases, a full table scan could be considered to be more efficient. There could be other reasons too.

Marc Perkowitz
MTP Systems Consulting

In a message dated 12/19/00 4:54:14 PM Central Standard Time, kevin_at_dulcian.com writes:

<< We are running a simple little query.  

 SELECT this_ID
 FROM table
 WHERE that_ID = 5  

 When executing the query with the database in choose mode it seems to want  to do a full table scan, ignoring the index in the where clause.  If we set it to RULE based mode obviously it works. What I am trying to  convince my partner of is that it is not necessarily "wrong", it's just the  way that the CBO wants to do it. We have analyzed the schema, the table and  the indexes and this is the way it wants to go.  

 My question is, am I wrong? Is this a problem that I need to be concerned  about?
 Any help would be appreciated. Received on Tue Dec 19 2000 - 16:59:16 CST