Re: Table join expertise needed badly

Mark, the OP said that all the other tables can be related back to one table which makes this table, A, the logical point where many developers would start. However, table A may not be the best starting point because of the lack of filtering conditions. By looking at the other table entry points (know column values) it may be possible to identify a join of two or more tables that provide an entry point into the main table that filters out a high percentage of the rows.

By figuring out a solution path manually this can then be compared to the plan the CBO produces. A comparison of the two and some analysis of the differences can then provide an idea of if the DBA/developer recongizes facts the optimzer missed or if the optimzer recognized possibilities that DBA/developer missed. This then serves as input to another attempt at determining an acceptable, perhaps even optimal, plan. If the ending plan paths are different between the CBO and developer the the two plans can be tested against one another.

HTH -- Mark D Powell -- Received on Sun Apr 16 2006 - 12:07:48 CDT